learner guide for cambridge international as & a level biology

Learner Guide

Cambridge International AS & A Level

Biology

9700

Cambridge International Examinations retains the copyright on all its publications. Registered Centres are permitted to copy material from this booklet for their own internal use. However, we cannot give permission to Centres to photocopy any material that is acknowledged to a third party even for internal use within a Centre. © Cambridge International Examinations 2015 Version 2.0 Updated: 16.02.16

Contents

How to use this guide ....................................................................................................... 3Section 1: How will you be tested?Section 2: Examination adviceSection 3: What will be tested?Section 4: What you need to knowSection 5: Useful websitesSection 6: Appendices

Section 1: How will you be tested? ..................................................................................... 5About the examinationsAbout the papersAbout the practical papers

Section 2: Examination advice ............................................................................................. 7General advice Advice about the questionsAdvice about the papers

Section 3: What will be tested? .........................................................................................32

Section 4: What you need to know ...................................................................................34How to use the table

Section 5: Useful websites ................................................................................................ 72

Section 6: Appendices ....................................................................................................... 75Mathematical skillsMore information about the examination

2 Cambridge International AS and A Level Biology 9700

How to use this guide

3Cambridge International AS and A Level Biology 9700


The guide describes what you need to know about your Cambridge International AS and A Level Biology examination.

It can be used to help you to plan your revision programme for the theory examinations and will explain what we are looking for in the answers you write. It can also be used to help you revise by using the table in Section 4, ‘What you need to know’, to check what you know and which topic areas of biology you have covered.

The guide contains the following sections:

Section 1: How will you be tested?This section will give you information about the different types of theory and practical examination papers that are available.

Section 2: Examination adviceThis section gives you advice to help you do as well as you can. Some of the ideas are general advice and some are based on the common mistakes that learners make in exams.

Section 3: What will be tested?This section describes the areas of knowledge, understanding and skills that you will be tested on.

Section 4: What you need to knowThis shows the syllabus content in a simple way so that you can check:

• the topics you need to know about

• the contents of each part of the syllabus

• details about each topic in the syllabus

• how much of the syllabus you have covered

Section 5: Useful websites

Section 6: AppendicesThis section covers the other things you need to know, including:

• information about the mathematical skills you need

• information about terminology, units and symbols, and the presentation of data

• the importance of the command words used in the examination papers

Section 1: How will you be tested?



About the examinationsThere are three ways you can gain a Cambridge International Advanced Level qualifi cation.

• take the Advanced Subsidiary (AS) qualifi cation only

• follow a staged assessment route to the Advanced (A) Level by taking the AS Level papers and the A Level papers in different examination sessions. Usually this means taking the AS Level papers at the end of one year of study and the A Level papers at the end of a second year of study.

• take all the examination papers in the same examination session leading to the full A Level

AS LevelYou will be entered for three examination papers, two theory papers and one practical paper.

You will take Paper 1 Multiple Choice (theory), Paper 2 (theory) and Paper 3 (Advanced Practical Skills).

A LevelYou will be entered for two further examination papers, Paper 4 A Level Structured Questions (theory) and Paper 5 Planning, Analysis and Evaluation.

About the papersThe table gives you information about the examination papers.

Paper number

How long and how many marks?

What’s in the paper? Weighting %

AS A

1 1 hour (40 marks)

40 multiple-choice questions. You choose one answer you consider correct from a choice of four possible answers.

31 15

2 1 hour 15 minutes (60 marks)

Structured questions. You should write your answers in the spaces provided. The paper tests the AS syllabus only.

46 23

3 2 hours (40 marks)

A practical test set and marked by Cambridge. It will include experiments and investigations based on the AS syllabus.

23 12

4 2 hours (100 marks)

Structured questions, totalling 85 marks plus one free response question that carries a further 15 marks. Based on the A Level syllabus, but a knowledge of the AS syllabus is required.

– 38

5 1 hour 15 minutes (30 marks)

A written paper that tests the practical skills of planning, analysis and evaluation. It will include information about experiments and investigations from both AS and A Level.

– 12



About the practical papersTwenty-three percent of the marks for Cambridge International AS Biology are for practical work.

In Paper 3, you will have to handle familiar and unfamiliar biological material and will be expected to show evidence of the following skills:

• manipulation, measurement and observations

• presentation of data and observations

• analysis, conclusions and evaluation.

When unfamiliar materials or techniques are involved, you will be given full instructions. One question will require the use of a light microscope.

No dissection will be set in Paper 3.

If you continue to a full A Level, after AS, the mark you obtained in Paper 3 will contribute twelve percent of your overall mark and Paper 5 will contribute a further twelve percent.

In Paper 5, there will be questions in which you will be expected to design an investigation and write out a plan that you will not carry out, as well as analysing and evaluating experimental data. To do this confi dently you need plenty of experience of practical work in the laboratory.

Questions involving an understanding of the use of the t-test and the chi-squared test may be set. You will be provided with the formulae for these tests.

Section 2: Examination advice



Much of this advice is given in response to the types of answers that learners have written in the past. It is presented under various subheadings to help you to prepare for your examinations. Some examples of questions and answers are included to illustrate some of the advice.

• Make sure that you read all the general advice. These can be important in any of the papers that you take.

• Have a copy of the syllabus to look at as you read through this section. Note that in Section 4 the fi rst part is the AS Level syllabus and the second part is A Level.

• Make sure that you know the examination papers that you are taking before you look at the advice for the different papers.

• At AS Level, you will take

– Paper 1, which is a multiple-choice paper.

– Paper 2, which consists of short-answer questions.

– Paper 3 which is the practical paper.

There are different versions of each paper; for example, Papers 11, 12 and 13 are all multiple-choice papers.

• At A Level, you will take

– Paper 4, which has a short-answer section for 85 marks and an essay for 15 marks.

– Paper 5, which tests your skills of planning, analysis and evaluation. It is not a practical paper like Paper 3, but does require a lot of experience of practical work.

General advice • Use your syllabus all the time while you are revising and preparing for the examination papers. You must

know which topics you will be tested on.

• Make sure you have all the equipment you will need for the exam in a clear, plastic container. You need two pens, pencils (preferably HB or B), a clean eraser, a ruler (which measures in mm), a pencil sharpener and a calculator.

Answering questions• The questions are designed to test your knowledge and understanding and your ability to apply the skills

you have gained during the course. When you are writing your answers remember that another person has to be able to read them.

• Do not waste time by writing out the question before you start to answer.

• Keep your handwriting clear and legible.

• Keep your answers on the lines on the question paper. Do not write in the left hand or right-hand margins of the paper.

• If you wish to change an answer, cross out your fi rst answer and rewrite. Do not write over what you have already written.



• If you have to cross out something, put a line through it; do not scribble over it.If you run out of space, use white space on another part of the exam paper for a continuation answer; do not try to squeeze in your answer by using very small writing.

• If you have to use a different space for a rewritten answer or to continue an answer, put a note to tell the Examiner where it is, e.g. “see page 5” or “see back page”.

• Always try to write accurately using the correct biological terms. This often helps you to give a better answer.

• If you want to use the word “it” or “they” – think “what is it?” or “what are they?” and then phrase your answer more precisely.

• If you want to use the word “affect” or “effect” – remember to write “how they affect” or “what effect do they have?”

Example 1

Question

Chronic obstructive pulmonary disease (COPD) is a progressive disease that develops in many smokers. COPD refers to two conditions:

• chronic bronchitis

• emphysema.

(i) State two ways in which the lung tissue of someone with emphysema differs from the lung tissue of someone with healthy lungs [2]

Correct answer for two marks

1 There are fewer alveoli than in a healthy lung.

2 The surface area for gas exchange is much smaller.

From the wording of the question it is clear that the answers refer to the lung tissue of emphysema.

Ambiguous answers for no marks

1 There are many air spaces.

2 There is less diffusion of oxygen and carbon dioxide.

3 There are fewer capillaries.

Both types of lung tissue have many air spaces. The technical term alveoli should be used as in the correct answers. Even though the third answer is correct, it will not be marked as the question asks for two ways.

• Do not write the fi rst answer that comes into your head. You are unlikely to think of exactly the correct phraseology or have all the necessary detail to answer the question. Plan what you intend to write before you start writing.

• Remember to read the question carefully, plan an answer, write the answer clearly, re-read the question, re-read your answer and then make any additions or corrections clearly. Always re-read your answers to check them against the question.

• During your course you will probably have seen many mark schemes from past papers. Do not learn them. If you write out a mark scheme that you have learnt, it is unlikely to gain you many marks and



often none at all, as it is very unlikely to be relevant to the exact question you were supposed to be answering

• Be prepared for questions on aspects of practical biology; they can appear on all the papers, not just Papers 3 and 5.

TermsThese are the technical words used in biology. Many of them are given in the syllabus. These terms will be used in questions. You will give a better answer if you can use them correctly in your examination. Ask your teacher if you are unsure of the meanings of the biological terms used in the syllabus and in any textbook you are using. You will notice that many terms you need to know are stated in the syllabus, so that is a good place to start when making your own dictionary. It would be a good idea to write concise defi nitions for yourself and use them to start your own biological dictionary using your class notes, websites and the glossaries from the back of textbooks.

• Try to use the correct spelling. If you cannot remember how to spell a word, write it down as best you can. The examiners will probably recognise what word you mean; if the spelling is too far out or ambiguous, then they cannot allow you a mark.

• Some biological terms have very similar spelling. Make sure you write clearly and always try to spell as accurately as you can.

• Do not try to mix the spellings of two words when you are not sure which of them is the correct answer. For example, you might write “meitosis” when you are not sure whether the answer is mitosis or meiosis. This answer will not get a mark.

Writing in your own wordsYou often have to write two or more sentences to answer a question.

• Use short sentences. If you write long sentences you can become confused and your meaning is lost. You might also write something contradictory. It is hard for the examiner to fi nd correct statements in a muddled answer.

• You are often asked to write down something you have learned. Make sure you have learnt the meanings of the common terms used in biology, e.g. active transport, osmosis, photosynthesis and respiration.

• During your course take every opportunity to read and write as much as you can to improve the way you express yourself.

Advice about the questionsThe marks• Always look to see how many marks are available for each question.

– In Paper 1 there is one mark for each question.

– The number of marks is printed on the examination papers for Papers 2, 3, 4 and 5. The mark available for each part question ((a), (b), (c)(i), etc.) is printed in square brackets, e.g. [2]. The number of marks helps you decide how much to write. The total number of marks for each question is printed at the end of the last part question, e.g. [Total: 12].

– The number of marks is a guide to how long to spend on each part of a question.



• Do not waste time and write a long answer for a question which has one or two marks. You will not get any extra marks even if your answer is full of many correct and relevant statements.

• If there are two or more marks do not write the same thing in two different ways, e.g. “The leaf is very large. The leaf has a large surface area”. Notice that the second sentence is more accurate and is preferable to the fi rst one.

The instructionsThese are called command words and tell you what to do.

• You can fi nd all the command words in the Glossary of command words used in science papers in the syllabus.

• If a question asks you to ‘name’ or ‘state’ two things only the fi rst two will be marked. Use the numbered lines for your answers if they are given on the question paper. If you write more than two and the fi rst is correct, the second one is wrong, and the third one correct, you will only get one mark (see Example 1).

• Some questions have two commands in the question, for example ‘predict and explain’. This means that you have to say what you think will happen AND then say why you think it will happen. Usually the word and is printed in bold type to help you. See the section below for advcie about answering questions that have two command terms and require an extended answer.

• Make sure you know what you should do in response to each command word.

Example 2

Question

A learner investigated the effect of increasing the concentration of sucrose on the rate of activity of sucrase. The results are shown in Fig. 4.1.

The graph in Fig. 4.1 shows that as the substrate concentration increases the rate of activity of sucrase increases to a constant level.

Describe and explain the results shown in Fig. 4.1.

It is quite easy to forget that there are two parts to this question. Before writing your answer it is a good idea to write description at the beginning of the fi rst of the answer lines and then explanation about half way down. You could write these in pencil and rub them out when you have fi nished your answer. Alternatively, you may choose to write a description of the fi rst part of the graph (activity increases) and then explain it followed by a description and explanation of the plateau on the graph. That is also a perfectly acceptable way to answer the question.

The questions• Make sure you know which part of the syllabus is being tested.

• Read the whole of a question carefully including all the stimulus material and parts (a), (b), (c) (i) and (c) (ii), etc. before you begin to answer. Some of the parts may have similar answers so you need to work out the differences between them. If you write exactly the same thing in different parts of the same question, the answer cannot be correct for both parts.

• There is often stimulus material for each question. This might be a photograph, diagram, drawing, fl ow chart, table of data, graph or just some text. Read all of this information carefully and study any pictures, tables or graphs that are included. All of it is relevant to the questions.



• The stimulus material is often about something you have not studied. Do not panic. There will be enough information in the question for you to work out an answer. You are being tested on your ability to apply your knowledge to new information.

• All the different parts of a question may be about the same topic, e.g. cells structure from Section 1 or blood from Section 8, but you should be prepared for questions that test different topics, e.g. the structure and function of white blood cells (phagocytes and lymphocytes) involving sections of 1, 8 and 11.

• Look for clues in the wording of the questions.

• If you are only given a Latin name or a name you do not recognise, e.g. impala, look to see if you are told anything about it. If in a question on Section 18 you are told that impala are herbivores, then you know they eat plants.

• Answer each question as far as you can. Do not spend a long time staring at a question.

• If you do not know the answer or how to work it out, then leave it and come back to it later. It is best to put a mark by the side of the question so you can fi nd it easily. An asterisk (*) is a good idea or a large question mark against the letter of the part question. Not all part questions have answer lines. You may not realise that you have left out a part question when you check through your answers towards the end of the examination.

• Try not to leave blanks. Always check through your answers towards the end of the examination. When you come back to a question you may remember what to write as an answer to a question that you left out earlier in the exam.

• Do not waste time by writing about things unrelated to the question.

Command words and phrasesExaminers use command words to help you to understand what they are looking for in your answer. This table explains what each of these words or phrases means and will help you to understand the kind of answer you should write. The list of command words is in alphabetical order. You should remember that the meaning of a term may vary slightly according to how the question is worded.

• You can fi nd out more about command terms in the Glossary of command words in the syllabus. These notes should help you respond to each of the command words.

Command words What you should do in response to each command word

Defi ne Give a defi nition – these should be concise defi nitions

What do you understand by the term .....? Give a defi nition or a fairly brief explanation of what the term means. You can use an example to illustrate if this seems appropriate

State Give a brief answer – maybe one word or a phrase

List A number of brief answers should be given; usually you are asked for a specifi c number of points. You do not gain extra marks by writing more than the number stated

Describe You may have to describe the steps in a process or describe the appearance of a biological structure.

You may also have to describe some data given in a table or a graph. Make sure you have the correct vocabulary for such a description. For example, use the words increase, decrease, constant, peak, maximum, minimum, etc.




Explain This is not the same as describe. You should give an answer that has some reasons. You may have to explain why something happens or how it happens

Discuss You may be asked to discuss advantages and disadvantages – so make sure you give some of both. Much depends on the type of question, but ‘discuss’ usually means you should give different sides of an argument

Outline This is not the same as describe. You should give the main important points without any detail

Predict This means you should state what you think will happen. You may be asked to justify your prediction or explain it; explanation is not required if all the question says is “predict....”

Suggest This is often used when there is no single correct answer; you should look through the information you have been given for some clues as to what to ‘suggest’ in response to the question. Many problem-solving questions use this command word

Calculate This is obvious; make sure you know how to calculate means, percentages, percentage changes, rates and ratios (e.g. for genetics). At A Level, you should also know how to use the formulae for standard deviation, standard error, the chi-squared test and the t-test. Always give your working even if not asked. Always make sure you use the correct units

Measure You should use a suitable measuring instrument to take a reading. Often this involves using a ruler to measure to the nearest mm. Make sure you write down the unit after the numerical answer

Determine This is not the same as ‘measure’. Often this means that you should explain how an experiment could be set up to take measurements and how you calculate the answer from the results.

Estimate You do not have to give an accurate answer – but your answer (which is usually numerical) should be approximate

Sketch This is usually used about graphs. You should put a line (straight or curved) on a pair of axes. This may be a graph that has a line on it already or it may be a pair of axes printed on the exam paper without a line or curve

Deduce This is used in a similar way to predict, except you will need to support your answer with a statement e.g. referring to a principle, or theory, or including reasoning with your prediction.




Find This is a general term which can mean several similar things, such as calculate, measure, determine, etc.

Give a reason/reasons See ‘Explain’.

Meant (what is meant by the term…) See ‘Understand’.

Understand(what do you understand by the term...)

You should (i) defi ne something and (ii) make a more detailed comment about it. The amount of detail depends on the number of marks awarded; e.g. explain what you understand by the term transcription.

The style of questionsWe use a great variety of different styles of questions. If you answer plenty of past papers during your course you will gain lots of practice at these. Here are some:

• Putting ticks and crosses in a table to make comparisons. For example, comparing the properties of different biological molecules.

• Completing tables of information by writing in single words, numbers or short phrases, e.g. what happens to the four valves in the heart during different phases of the cardiac cycle.

• Completing a passage of text with the missing terms.

• Writing defi nitions – make these as concise as you can; there is no need to use any examples unless asked.

• Making a list – answers should also be concise; detail is not required.

• Matching pairs from two lists, e.g. matching the names for the stages of mitosis with descriptions of what happens inside a cell during this type of nuclear division.

• Putting stages of a process into the correct sequence, e.g. the stages of protein synthesis.

• Labelling a diagram – label lines may already be on the diagram or you may have to add them yourself.

• Completing a genetic diagram (Paper 4).

• Describing and/or explaining data from a table or a graph.

• Explaining aspects of an investigation, e.g. a learner investigation that you might have carried out or a piece of research that has been adapted from a scientifi c paper.

• Adding information to a fl ow chart.

• Writing a fl ow chart from information that you are given, e.g. drawing a food web from written descriptions of the feeding relationships in a community.

The information in the question • Questions may ask you to “Use examples from...” or “Use only the information in ....” or “With

reference to Fig. 6.2”. If you read instructions like these, fi nd out what you are expected to use as examples or take information from. You will not get any marks if you use examples from somewhere else. The information can be given to you in different ways:

– a diagram, such as a food web, a set of apparatus or a biological structure;



– a graph, which could be a line graph, a bar chart or a histogram – always check the headings and units carefully;

– a table – always read the headings of the columns and/or rows carefully and look for any units.

Tables and graphsThe stimulus material may be in the form of a table, line graph, bar chart or histogram.

• Always read the introductory text very carefully before you study the table or graph. Underline key points in the information that you are given. In Papers 4 and 5, there may be quite a bit of introductory text explaining how the information was collected.

Tables

• Look at the column and row headings in a table and make sure you understand them. If you have read the introduction carefully, then you will.

• Find the units that have been used. Make sure that you use the units if you give any fi gures in your answer.

• Use a ruler to help read the table. Align the ruler with the fi rst column. This should be the independent variable and should increase in steps. Now put the ruler to the right of the next column and look at the fi gures in this second column that should be the dependent variable. Look for a pattern or trend in the fi gures. Identify the pattern or trend fi rst before thinking of an explanation. Move the ruler across to the right of the third column if there is one and continue in the same way. It may help to sketch a little graph on the exam paper to help you identify any pattern or trend.

Line graphs

• Look carefully at the x-axis which is the independent variable and make sure you understand what has been changed. Look carefully at the y-axis which is the dependent variable. Both variables should be described in the introduction to the question.

• Put your ruler against the y -axis and move it gradually across the graph from left to right. Follow the pattern or trend of the line (or each line if there is more than one). Mark on the graph where something signifi cant happens. For example, the line might show that the dependent variable becomes constant (gives a horizontal line).

• Use your ruler when taking fi gures from the graph. If the graph is plotted on a grid, then the examiners may allow ± one small square or half a small square in taking your readings. If you use a ruler and rule lines on the graph, you should take exact readings.

Bar charts and histograms

• Look carefully at the x-axis and the y-axis to see what has been plotted. Again, it is a good idea to move a ruler across the bar graph or histogram from left to right to help you concentrate on one aspect at a time. You can identify the highest and lowest fi gures and see if there is any pattern.

• You should make yourself some notes about the table, graph or histogram before answering the questions.

Calculations

If you are asked to do a calculation you may have to fi nd the fi gures from a table or graph.

• Write out all the working for your calculation. If you make a mistake and give the wrong answer, you may well be awarded marks for showing how to do the calculation.

• Make sure that you show the units in the calculation.



• Make sure you include the units if they are not given on the answer line.

• Always express your answer in the same way as other fi gures provided, e.g. in a table. If the other fi gures are 5.6 and 4.6, then your answer should be given to one decimal place, e.g. 2.0 and 7.0, not 2 and 7.

• Round up or down the result on your calculator – do not copy all the fi gures after the decimal point.

Making comparisons• If you are asked to compare two things make sure you make it clear which thing you are writing about.

• The question may ask you to compare two structures or two processes that you have learnt about. Sometimes you may be expected to do this on answer lines in which case you must make clear the items that you are comparing (see Example 4).

• You may be given a table to complete. This may be blank and you have to fi ll it in, or it may already have some entries and you complete it.

• If you are given lines to make the comparison, it is perfectly acceptable to draw a table for your answer.



Example 3

Question

State two ways in which arteries differ from veins. [2]

Correct answer:

1 Arteries have thicker walls than veins.

2 Veins have semi-lunar valves, but arteries do not.

Ambiguous answer:

1 They have thick walls.

2 They don’t have valves.

No marks would be given to the last two answers as the comparisons have not been made.

Question

Complete the table to compare the structure of arteries with the structure of veins. [2]

Correct answer

arteries veins

have thick walls have thin walls

have thick muscle layer have very thin muscle layer

Incorrect answers as the comparisons are not made between the same features

arteries veins

thick wall thin elastic tissue

no valves small amount of muscle

In cases like this, it is much better to have an extra column that gives the features to be compared:

feature arteries veins

thickness of wall thicker thinner

valves absent present

This extra column makes sure that you make direct comparisons in each row of the table. You can always add a fi rst column if it is not included in the question.



Extended writing• You are required to write longer answers to questions that have four or more marks. There are more

of these questions in Paper 4 than in the other papers. You do not have to write your whole answer in prose. You can use labelled and annotated diagrams, fl ow charts, lists and bullet points. However you present your material, you should write enough to make your meaning clear.

Example 4

Question from Paper 2

Explain, in terms of water potential, how water moves from the xylem in a leaf to the air outside a stoma. [4]

This question requires a sequence, i.e. from xylem to cell walls of mesophyll cells; from walls to air spaces inside the leaf; from air spaces through the stoma to the air outside the leaf. The movement of water in each stage needs to be explained in terms of cohesion-tension, evaporation and diffusion. Writing out the pathway on its own does not get any marks.


(a) Explain how changes in the nucleotide sequence of DNA may affect the amino acid sequence in a protein. [7]

(b) Explain how natural selection may bring about evolution. [8]

[Total: 15]

In (a), you may fi nd it easier to use some examples to show how changes in nucleotide sequences lead to changes in amino acid sequences. You do not need to know the genetic code, but you can use changes in DNA triplets to show what will happen, e.g. AAA changes to TAA. In (b), you should have learnt several key points about natural selection that you can write down in a logical sequence.


(a) Describe the part played by the proximal convoluted tubules in the functioning of the kidneys. [8]

(b) Explain how the collecting ducts in the kidneys may reduce the loss of water from the body. [7]

[Total: 15]

A diagram of a cell from the proximal convoluted tubule might help your answer to (a). You can label and annotate your diagram to illustrate your answer. A feedback loop (a type of fl ow chart) would be a good way to illustrate part (b).

– When you answer these questions always use full sentences if you can. If you fi nd it helps to write bullet points, then make sure that each bullet point is a full sentence. If you abbreviate your answer too much by writing notes, then you may not convey enough information to gain the marks.

– If you are giving a sequence of events (as in Example 5), then you should make sure they are in a logical order. If you are explaining a biological principle or making comparisons, then give the main points fi rst.

– If you are describing something that moves from one place to another as in the Paper 2 question from Example 5, then make sure you include the direction of movement. For example, ‘water moves by osmosis’ is unlikely to gain a mark unless you include the direction; ‘water enters the mesophyll cell down the water potential gradient’ is a much better answer.



Advice about the papersPaper 1 Multiple Choice• You have about one minute to read and answer each question. Each question may test one topic or

several topics from different parts of the AS syllabus.

• Some questions test what you know and understand.

• Some questions test if you can apply what you have learnt to understand new data. These questions will often have a diagram, graph or table to use.

• Some of the choices can be very similar; read carefully and underline words that make each choice distinct from the other three.

• Try to decide what the question is testing as you are reading it. The sequence of questions usually follows the sequence of topics in the syllabus. Therefore you can expect the early questions to ask about cells and biological molecules and those at the end to be on infectious disease and immunity.

• Do not try to fi nd a pattern in the order of your answers (e.g. A, B, C, D, A, B....)

– The same letter could be the correct answer for several questions in a row.

– Letter A might be the correct answer for more questions than B, C or D. Or there could be fewer correct answers shown by letter D than any of the others.

– Do not let what you have chosen for the previous questions infl uence which letter you choose.

• Some questions may ask about aspects of practical work, for example about different variables: independent, dependent and controlled.

• It is important to understand how to use terminology, e.g. how to apply water potential terminology to problems on cells and osmosis.

Paper 2 AS Level Structured Questions• This paper has a mix of short-answer questions and those requiring slightly longer answers. There is no

essay.

• Longer answers will need four or fi ve sentences with two or three different ideas. Always look at the number of marks for each part question to help you decide how much to write.

• Look at the number of command words: ask yourself ‘do you have to do one or two things?’. See Example 2.

• Use the lines given. Stick to the point and do not write too much.

• Only give the number of answers that are asked. Use the numbered lines and give one answer per line.

• There will only be a few parts of questions that need extended writing. These will have four [4] or fi ve [5] marks. These questions will often be related to some information you are given. You will need to write four or fi ve sentences in a sequence that makes sense. You can think of it as “telling a story with a beginning, a middle and an end”. Remember to refer to any information you are given.

Paper 3 Advanced Practical SkillsGeneral advice

Success at Paper 3 requires you to do plenty of practical work during your course and have several attempts at past paper questions to fi nd out how to complete everything in the time available. During the practical exam you will have to make some decisions; if you practise plenty of past questions you will fi nd out what



sort of decisions to expect. As you revise, make sure you know exactly how to carry out the practical procedures described in the AS syllabus. You will be assessed on your skills at:

• manipulating apparatus to collect results and make observations

• data presentation

• analysis of results and observations

• evaluation of procedures and data.

You should make decisions, such as:

• identifying variables

• standardising the control variables

• how to change the independent variable

• choosing the number of measurements to take

• deciding the intervals between the values of the independent variable

• choosing a control experiment

• identifying any risks and stating appropriate precautions.

During the examination

• Read through the questions carefully, looking to see how many marks are given for each question.

• Read the instructions to the end; do not start a practical procedure without reading carefully all the steps involved.

• As you read, check that you have the apparatus and materials described. If not alert the supervisor.

• Think about the apparatus that you will use for each step and imagine using it in your mind.

• Make sure that you have a sharp pencil to use for making drawings and for drawing graphs and charts. Do not draw in ink because you cannot make changes as you can when using a pencil.

• Make sure you have a good, clean eraser for rubbing out your pencil lines if necessary. Do not press too hard when using a pencil for making drawings, graphs or charts. Sometimes it is hard for an examiner to tell which is your fi nal line.

Following the instructions

• Follow the instructions for practical methods exactly. If you make a change in the method it may alter the results.

• Do not take short cuts.

• Always label test-tubes and other containers to help you remember which is which.

• If you are told to “Wash the apparatus thoroughly after each use” make sure you do. If there is anything left in the apparatus the next stage may not work.

• It is a good idea to put a tick by the side of each instruction when you have completed it. This helps you to fi nd the right place in the instructions, so that you do not leave out a step or repeat a step when it is not required.

• Keep your exam paper on a part of the bench which you can keep dry. Do not pour liquids or use syringes or pipettes over your exam paper. If you keep your exam paper away from the ‘wet’ part of your bench you are unlikely to spill anything on it.



Recording your measurements and observations

You are expected to make observations and record them.

• You can record your observations:

– as statements in writing

– in tables

– by using drawings

– by constructing tally charts.

You will take readings from different apparatus. You must make the measurements as accurately and reliably as you can. Numerical readings will normally be collected and presented in a table.

• Follow the instructions below about drawing tables.

• Make clear descriptions of colours and colour changes; refer to ‘blue’, ‘orange’ and ‘purple’ when describing reagents used in biochemical tests. You may want to refer to slight differences, so use words like ‘pale’ and ‘dark’.

• Make your measurements as accurate and reliable as possible.

• Accurate results are close to the actual or ‘true’ values; reliable results are those that are repeatable.

• If you can take repeat readings, then do so. There is not always enough time to do this.

• You can process your observations by:

– carrying out calculations, e.g. percentages and percentage changes

– plotting graphs – line graphs, bar charts and histograms.

• Use all the space available on the paper for your observations.

• Do not write an explanation until the question asks for one.

• Use a sharp HB or B pencil. It can be rubbed out easily if you need to correct a mistake. Use a good eraser so that is clear to the examiner which is your fi nal line.

• Do not forget to include headings for the columns and the rows in tables.

Drawings

These will be from microscope slides or photographs.

• Read the question carefully, the drawing may have to be an accurate size e.g. twice the original.

• Make each drawing as big as the space allows without writing over the text of the question and making sure that you leave enough space for labels and annotations, if asked for.

• Use a ruler for labelling lines.

• Draw and label in pencil.

• Use one clear continuous outline not an artistic drawing. Do not shade.

• Observe details carefully, such as the relative number of chloroplasts in different cells and the thickness of cell walls in different cells in a vascular bundle. Show these accurately on your drawing.

A plan diagram shows the distribution of tissues in a section. It also shows the proportions of the different tissues. Although called a low power plan diagram you may use high power to identify the different tissues



and to be sure you are putting the boundaries of those tissues in the right place. You should not draw any cells in a lower power plan diagram.

When you make a plan diagram, follow these simple rules:

• make the drawing fi ll most of the space provided; leave space around the drawing for labels and annotations (if required by the question)

• use a sharp HB or B pencil (never use a pen)

• use thin, single, unbroken lines (often called ‘clear and continuous lines’)

• show the outlines of the tissues

• make the proportions of tissues in the diagram the same as in the section

• do not include drawings of cells

• do not use any shading or colouring.

Add labels and annotations (notes) to your drawing only if you are asked for these in the question. Use a pencil and a ruler to draw straight lines from the drawing to your labels and notes. Write labels and notes in pencil in case you make a mistake and need to change them. You may leave your labels and notes in pencil – do not write over them in ink.

High power drawings should show a small number of cells and they should be drawn a reasonable size so you can show any detail inside them. When you make a high power drawing, follow these simple rules:

• make the drawing fi ll most of the space provided; leave space around the drawing for labels and annotations (if required by the question)

• use a sharp HB or B pencil (never use a pen)

• use clear, continuous lines (see above)

• draw only what is asked in the question, e.g. three cell types or one named cell and all cells adjoining it

• show the outlines of the cells

• the proportions of the cells in the drawing must be the same as in the section you are drawing

• plant cell walls should be shown as double lines with a middle lamella between the cells; the proportions of cell walls should be drawn carefully.

• show any details of the contents of cells – draw what you see, not what you know should be present; for example, in plant cells you may see nuclei, chloroplasts and vacuoles

• do not use any shading or colouring.

Taking measurements of specimens and photographs

Using an eyepiece graticule

An eyepiece graticule is a scale that fi ts inside the eyepiece on your microscope. It allows you to take measurements of the specimens you view with the microscope. You can measure simply in graticule units, but you may be asked to make an actual measurement which involves calibrating the graticule using a stage micrometer. This is done by lining up the graticule with the divisions on the micrometer.

• Make your measurements as accurate as you can. You will probably be able to measure to the nearest division on the graticule.

• You may be asked to take several measurements and then calculate a mean.



Taking measurements from photographs

You may have to measure an object on a photograph and calculate the actual size of a structure or the magnifi cation of an image.

• Always measure photographs in millimetres, not centimetres.

• If you have to use your measurements in a calculation, write neatly and show your working. The person marking your paper might be able to give you marks for knowing what to do even if you make a mistake or do not fi nish the calculation.

Presenting data and observations

Tables

Before you start to draw a table, decide what you wish to record. Decide on how many columns and how many rows you will need. Make sure you have read all the instructions before you draw the table outline. Follow these rules:

• use the space provided, do not make the table too small

• leave some space to the right of the table in case you decide you need to add one or more columns

• make the table ready to take observations or readings so that you can write them directly into the table rather than on another page and then copy them into the table (tables need to show all the raw data you collect)

• draw the table outlines in pencil

• rule lines between the columns and rows

• rule lines around the whole table

• write brief, but informative headings for each column

• columns headed with physical quantities should have appropriate SI units

• when two or more columns are used to present data, the fi rst column should be the independent variable; the second and subsequent columns should contain the dependent variables

• entries in the body of the table should be brief – they should be single words, short descriptive phrases or numbers

• data should be recorded in the table in the order in which it is collected – this is because the table is prepared before the data collection. For example, if the instructions state that results from the highest temperature or highest pH is to be recorded fi rst then these go at the top of their respective columns. It is more usual to arrange the values of the independent variable in ascending order (e.g. from 0 to 100) so that patterns are easier to follow and that is how data in tables for Papers 1, 2, 4 and 5 is usually presented

• numbers written into the body of the table do not have units (units only appear in the column headings).

You may have to process your results by calculating rates of reaction, changes in length, percentage changes or means of repeat readings. These processed results can appear in the same table with the raw data that you have collected or can be in a separate table with the independent variable.

The solidus or slash (/) meaning ‘per’ should not be used in units. For example, if you have to include concentrations as in a table you do not write g per 100 cm3 as g/100 cm3. It should always be written out in full using ‘per’ or, better, as g 100 cm–3. The negative exponent, cm–3, means ‘per’.



Note that the solidus is used to separate what is measured from the unit in which it is measured. You may notice that text books and examination papers use brackets around the units in tables. This is also an accepted convention, but the solidus is the convention used in Cambridge International AS and A Level Biology.

Correct and incorrect ways of showing units in tables and graphs

Correct Incorrect

either:rate / mm cm–3

or:rate (mm cm–3)

rate mm/cm3

either:concentration / g 100 cm–3

or:concentration (g 100 cm–3)

concentration g/100 cm3

A note on the uses of ticks and crosses in tables:

Do not use ticks and crosses in tables of results which should show observations, such as the colours obtained in biochemical tests.

Ticks and crosses may be used in tables of comparison if there is a key to explain what they mean,

e.g. = present; = absent.

You may want to show anomalous results in tables. If so circle them and put a note underneath the table to explain that they are anomalous results.

You may be asked to compare specimens viewed in the microscope and/or in photographs. These comparisons must be organised into a table. Draw your table so that it has a fi rst column for the features that you have observed. You can then present both similarities and differences:

Feature Specimen A Specimen B

Similarities

Charts and graphs

Bar charts have separate columns that do not touch – there are gaps in between; histograms have columns that do touch each other. Bar charts are used to show data on discontinuous variables, for example blood groups, eye colour, etc.; histograms are used to show data on continuous variables, e.g. length, mass, speed, volume, etc.



Bar charts

Bar charts should be used if the independent variable is qualitative. If you are investigating the rate of respiration of yeast when given different substrates, the independent variable is the type of substrate, e.g. glucose, maltose, sucrose, etc. In this case there is no continuous scale for the independent variable and a bar chart is the appropriate way to present the results. The dependent variable is continuous as it is the rate of respiration and would be measured in units such as ‘rate of carbon dioxide production/cm3 s–1’.

Rules for drawing bar charts:

• use most of the grid provided, do not make the chart too small

• draw the chart in pencil

• bar charts can be made of lines, or more usually, blocks of equal width. There must be space between the lines or bars. They do not touch

• the intervals between the blocks on the x-axis should be equidistant

• the y-axis should be properly scaled with equidistant intervals; the scale should usually start at 0 and this should be written at the base of the axis. If all the numbers are large a displaced origin may be used but the start number should be clear at the base of the y-axis

• the y-axis should be labelled with the headings and units taken from the table of results

• the lines or blocks should be arranged in the same order as in the table of results

• each block should be identifi ed; there is no need to shade the blocks or colour code them.

Histograms

Do not confuse bar charts with histograms. A histogram is drawn for continuous data that is subdivided into classes. A good example is collecting data on continuous variables, such as linear measurements or mass. Sometimes the intervals can be whole numbers, for example the numbers of seeds in fruits. If you are analysing data then you may wish to draw a frequency histogram to see if the data shows a normal distribution.

Histograms are used when the independent variable is numerical and the data are continuous. They are sometimes referred to as frequency diagrams.

First the raw data needs to be organised into classes.

• The number of classes needs to be established. This will largely depend on the type and nature of the data.

• The rule for determining the number of classes is 5 × log10 total number of readings.

• The range within each class needs to be determined; this is usually the total range divided by one less than the number of classes.

• There should be no overlap in the classes, e.g.4.01 to 5.20 or 4.01 < 5.215.21 to 6.40 or 5.21 < 6.41 (< = less than)



The data should be organised using a tally chart and drawing ‘fi ve bar gates’ as in //// = 5

Follow these rules when drawing a histogram:

• use most of the grid provided, do not make the histogram too small

• draw the histogram in pencil

• the x-axis represents the independent variable and is continuous. It should be labelled clearly with an appropriate scale

• the blocks should be drawn touching

• the area of each block is proportional to the size of the class. It is usual to have similar sized classes so the widths of the blocks are all the same

• the blocks should be labelled, e.g. ‘3.0 to 3.9’ which means that 3.0 is included in this class, but 4.0 is not. 4.0 will be included in the next class: 4.0 to 4.9

• the y-axis represents the number or frequency and should be properly scaled with equidistant intervals. It should be labelled with appropriate units.

Line graphs

Line graphs are used to show relationships in data which are not immediately apparent from tables. The term graph applies to the whole representation. The term curve should be used to describe both curves and straight lines which are used to show trends.

Follow these guidelines:

• use at least half the grid provided, do not make the graph too small

• draw the graph in pencil

• the independent variable should be plotted on the x-axis

• the dependent variable should be plotted on the y-axis

• each axis should be marked with an appropriate scale. The origin should be indicated with a 0. The data should be examined critically to establish whether it is necessary to start the scale(s) at zero. If not, you may have a displaced origin for one or both axes, but this must be made obvious by labelling the displaced origin very clearly

• each axis should be scaled using multiples of 1, 2, 5 or 10 for each 20 mm square on the grid. This makes it easy for you to plot and extract data. Never use multiples of 3

• each axis should be labelled clearly with the quantity and SI unit(s) or derived (calculated) units as appropriate, e.g. time/s and concentration/g dm–3; the axes labels and units must be the same as those in the table

• plotted points must be clearly marked and easily distinguishable from the grid lines on the graph. Dots in circles ( ) or small, neatly drawn crosses (x) should be used; dots on their own should not. If you need to plot three lines, vertical crosses (+) can also be used

• label each line carefully or use a key. Use a pencil for both lines; do not use a blue or black pen or different colours

• in Paper 3 there are usually fi ve or six results to plot.



After plotting the points you need to decide if any of them are anomalous. Ask yourself the question ‘do they fi t the trend?’. But what is the trend? You should know something about the theory behind the investigation so you should be aware of the likely trend. If you think one or more of the results are anomalous, then it is a good idea to ring them. Put a circle on the graph away from the line and put a key to state that the circled point(s) represent anomalous result(s). The next thing to decide is how to present the curve.

• It may be obvious that the points lie on a straight line; for example, the effect of enzyme concentration on the rate of an enzyme-catalysed reaction. If you have a result for the origin (0, 0) then that must be included and you can place a clear plastic ruler on the grid and draw a straight line from the origin making sure that there is an even number of points on either side of the line. If you do not have a result for the origin, then start the line at the fi rst plotted point. Do not continue the line past the last plotted point.

• You should only draw a smooth curve if you know that the intermediate values fall on the curve. You may be expecting the relationship to be a smooth curve and if the points seem to fi t on a curve then draw one. Again decide whether the origin is a point and, if not, start at the fi rst plotted point. The curve should go through as many points as possible, but try to make sure there is an even number of points on either side of the line. Do not continue past the last plotted point.

• In the practical examination you may only have fi ve or six results. These are likely to be single results rather than means of replicate results. Therefore you cannot be sure of the relationship and should not draw a straight line or a curve as described above. You should draw straight lines between the points. This indicates uncertainty about the results for values of the independent variable between those plotted.

• If a graph shows more than one line or curve, then each should be labelled to show what it represents.

Bar charts, histograms and line graphs should normally have informative titles. There is no need to give titles in the exam as it is obvious what they are. In all other circumstances give informative titles.

If you have times in minutes and seconds, never use minutes as the unit on a graph. It is very diffi cult to use a scale with each small square representing 3 or 6 seconds. Always plot results in seconds unless the unit for time is whole minutes.

Analysis, conclusions and evaluation

As part of analysis you should be able to:

• identify anomalous results. Anomalous results are those that do not fi t the trend

• process your results to calculate means, percentages, changes in mass or length, calculate percentage changes and rates of reactions

• fi nd unknown quantities by using axis intercepts or estimating from colour standards using known concentrations

• describe the pattern or trend in data

• make conclusions to consider whether experimental data supports hypotheses or not.

Processing results

You should be prepared to calculate:

• means

• percentages

• percentage changes

• rates of reaction by calculating 1/t or 1000/t; the unit used is s–1.



You should know how to use line graphs to:

• fi nd an intercept – where a line you have drawn crosses a key value on the x-axis; for example, fi nding the water potential of a tissue using percentage change in length of plant tissues

• fi nd the rate of a reaction by calculating the gradient of a line you have drawn.

As part of evaluation you should be able to:

• identify systematic and random errors

• systematic errors are those that affect all the results in the same way

• random errors do not affect all the results in the same way

• identify the signifi cant errors in your investigation

• estimate the uncertainty in measurements. The actual error is half the smallest division on the apparatus you are using

• assess how effective you have been at standardising variables

• suggest improvements to the procedure you have followed

• suggest ways in which the investigation might be extended to answer a new question.

Estimating uncertainty in your results

You may have to estimate the uncertainty or error in your results. For particular apparatus, the error is half the smallest graduation on the apparatus, e.g. if the smallest division is 1.0 cm3 then the uncertainty would be ±0.5 cm3. So if you start your measuring at 0 the uncertainty applies where you take your measurement – say at 6.3 cm3. So the result is expressed as 6.3 ± 0.5 cm3. BUT if you have to start at a measurement other than 0 (for example when taking readings from a burette) the uncertainty applies at both ends, so it is multiplied by two as there is an error at each end, e.g. 7.5 ± 1.0 cm3. Similarly, if using a ruler then there would be an error at each end unless you start at 0. The same applies to measuring a quantity in a syringe by sucking up from empty. The error would be half the minimum measurement. But when you take two readings from the syringe (say delivering 2.0 cm3 by moving the plunger from 6.5 cm3 to 4.5 cm3) the uncertainty is multiplied by two.

Percentage error is calculated as the error expressed as a percentage of the actual reading. For example if the reading is 7.5 ± 1.0 cm3, then the percentage error is 1.0/7.5 × 100 = 13.3%.

Conclusions

• Conclusions are brief statements supported with explanations using your knowledge from the AS syllabus.

• Use your own results for your conclusions.

• Before planning what to write for a conclusion, turn back to the beginning of the question and read the introduction. You may have forgotten what you were told about the investigation you have just carried out. Think about the theory and apply it to the results you have obtained.

• Sometimes you are expected to make conclusions about some other data, not the data you have collected.

• Do not write the conclusion you have learned from a class experiment or from theory.

• You should also consider the confi dence that you have in your conclusions. For this it is a good idea to consider whether:

– the standardised variables have been kept constant



– there were any other variables that were not standardised

– there were any anomalous results

– any replicate results were similar or not.

• If you are unsure about any aspect of the practical you have carried out, then you can say that you do not have confi dence in your conclusions and give a reason or reasons.

Suggesting improvements

You may be asked to suggest modifi cations or improvements that will increase the accuracy and reliability of the results. As you carry out the practical procedure you should think critically about it and make some notes. If asked to suggest improvements, then look back to these notes for ideas. You can suggest:

• ways to improve the standardisation of variables, for example by using a thermostatically-controlled water bath

• taking repeat readings (replicates) to assess the reliability of the data

• calculating mean results

• using a different way to measure the dependent variable so the results are more accurate

• using a different piece of apparatus to measure the dependent variable and reduce the percentage error (see above)

You may also have to justify your suggested improvements. When you do this, make sure you explain how they will improve the confi dence you have in the data and therefore in the conclusion.

Paper 4 A Level Structured QuestionsThere are 85 marks for Section A and 15 for Section B.

• Section A consists of structured questions that have a variable number of marks.

• Questions on genetics may have genetic diagrams to complete and chi-squared tests to carry out.

• Section B has two essays from which you must choose one. If you write answers to both essays then the higher mark will be the one that you are given. It is unlikely that you will gain a better mark by writing two essays in a hurry, rather than one which you have planned and written more carefully.

Paper 5 Planning, Analysis and EvaluationRemember that this is not a practical paper like Paper 3, but does require a lot of experience of practical work. The paper tests your skills of planning, analysis and evaluation. Each question is based on a practical investigation. You can expect that these investigations will be unfamiliar to you. The advice is the same as for other papers: read the information carefully, underline key words and phrases, annotate any diagrams, graphs and tables that you are given.

Paper 5 differs signifi cantly from Paper 3 in its approach to data presentation. As Paper 5 is a written paper rather than a practical paper you are not required to construct tables and complete them with observations or numerical results. You will be given data and be expected to carry out an analysis, interpretation and evaluation. This means that it is assumed that you understand how data is presented.

In Paper 5 you will be asked to do such tasks as:

• identify anomalous results



• process raw data, for example by calculating means, standard deviations, standard errors, ratios and correlations

• identify and describe patterns and trends

• explain raw or processed data.

In most cases the data is more complex than in Paper 3 and often involves making comparisons. Complex tables, where variables are being compared may have a different layout to the one given in Paper 3 and you should look carefully for the dependent variable. In some cases, the table layout means that the dependent variable is a table heading across several columns and the independent variable is given in a row underneath.

You may be asked to plot a graph using fi gures provided although this is less likely than on Paper 3. In addition to the rules given for Paper 3, you should know how to add error bars to line graphs or bar charts using standard deviation or standard error. You should certainly understand why error bars are added to graphs.

In other cases, a graph plotted from the results of an investigation may be given and labels for the axes required. In this case units would be expected which may be in table headings or may have to be deduced from information in the question. In some cases, arbitrary units are acceptable, although you are expected to be familiar with units used to measure common variables, such as light, temperature, time and volume.

Paper 5 may also use scatter graphs or correlation curves to show the effect of one variable on another. You should know how to interpret these forms of presentation.

You should know how to make a sketch graph to predict the results of an investigation. As always, the axes should be orientated with the independent variable as the x-axis and the dependent variable as the y-axis. Axis labels are expected. Units are not required in sketch graphs unless they are specifi ed in the question.

Planning investigations

One of the questions involves writing a plan for an investigation. You will be given some information about the investigation and this will be enough material for you to write your plan.

The skills that you are being tested on are:

1. Identifying key variables.

2. Describing a workable practical procedure.

3. Selecting appropriate methods for measuring the independent variable.

4. Selecting appropriate methods for varying and measuring the dependent variable.

5. Selecting appropriate methods for controlling other variables.

6. Suggesting a suitable control experiment.

7. Suggesting a quantitative, testable, prediction.

8. Selecting equipment of a level of precision appropriate to ensure accuracy.

9. Planning to collect suffi cient results to ensure reliability.

10. Describing how results will be recorded.

11. Suggesting how results will be analysed.

12. Risk assessing the practical procedure.



• When you read through the information provided on the paper, try to work out three main things:

1. what should be changed – this is the independent variable

2. what is going to be measured – this is the dependent variable

3. what should be kept the same – these are the control variables

• You should organise your plan under several headings and then write as concisely as possible. Suitable headings are:

– hypothesis and/or prediction

– variables

– risk assessment

– method

– collecting results

– analysis of results.

• Some investigations need to have two parts.

– The experimental – which measures the process being studied and contains the living organism, part of an organism (e.g. a leaf) or enzyme being tested.

– The control – which will be exactly the same as the experimental except that the living organism will be missing or replaced by something non-living. The control shows that the results are due to the activity of the living organism and is not due to the apparatus or an environmental factor.

• Make sure you explain carefully how to standardise the control variables; for example, ‘put test-tubes in to a thermostatically-controlled water bath’ is better than ‘keep the test-tubes at the same temperature’.

• All investigations should be repeated to increase the reliability of the results. If the same results are achieved (or the results are very similar) then they are reliable. You can also include the calculation of means and standard deviation in your plan under the heading of analysis of results.

• Always give quantities in appropriate terms – avoid the use of the word ‘amount’ as this does not convey precise meaning to any specifi c quantity. ‘Amount’ could mean volume, mass or concentration. For example, you can give the volume in cm3, mass in grams and concentration in an appropriate unit, such as grams 100 cm–3.

• Suggest appropriate volumes and concentrations in your plan. Include instructions on making up dilutions either by serial dilution or proportional dilution. You should have learnt how to do this when preparing for Paper 3.

• Choose apparatus that will give precise results. For example, if you are measuring using a syringe or measuring cylinder it may be diffi cult to measure to the nearest cm3. You should think about ways in which the precision can be improved before writing your answer.

• Write out your method as a list of numbered steps as if you are writing a set of instructions for someone else to follow. Think of your method as a recipe.

• Carry out a risk assessment on your plan and include a section headed risk assessment or safety precautions.

Analysing data, making conclusions and evaluation

In preparation for Paper 3, you will have learnt how to analyse data, draw graphs, evaluate data and experimental methods, and make conclusions. You will be tested on these skills in Paper 5. In addition, you should know about some statistical methods and apply them to the data provided.

There is always a question that asks you to analyse the data from an investigation. You should know about the following aspects of statistics:

• calculating standard deviation and standard error (formulae will be provided)



• using statistical tests – the chi-squared test, the t-test, and the Pearson and Spearman tests for correlation (formulae for these tests will be provided)

• making a null hypothesis.

You should know when and how to use these methods. There are several different styles of questions that test your understanding of these statistical methods. The best preparation is to look at the way data is presented in past paper questions and see what sort of questions are asked.

Section 3: What will be tested?



The assessment objectives (AOs) describe the knowledge, skills and abilities that you will be expected to demonstrate at the end of your course.

There are three main objectives:

AO1 Knowledge with understanding – what you remember and how you make use of what you know in both familiar and unfamiliar situations.

AO2 Handling information and solving problems – how you handle information provided in the question and how well you solve the problems posed.

AO3 Experimental skills and investigations

The theory papers test AO1 and AO2. The purpose of the practical papers is to test AO3. Your teacher will be able to give you more information about how each of these is used in the examination papers.

The following tables show you the range of skills you will need to develop:

Skill area You will need to demonstrate this skill in relation to:

AO1 Knowledge with understanding

biological phenomena, facts, laws, defi nitions, concepts and theories

biological vocabulary, terminology, conventions (including symbols, quantities and units)

scientifi c instruments and apparatus used in biology, including techniques of operation and aspects of safety

scientifi c quantities and their determination

biological and technological applications with their social, economic and environmental implications

Questions testing the skills in the table above will usually begin with one of the following words: defi ne, state, name, describe, explain or outline. See Section 6 for an explanation of these words.



Skill area You will need to use written, symbolic, graphical and numerical forms of presentation to:

AO2 Handling information and solving problems

locate, select, organise and present information from a variety of sources

translate information from one form to another

manipulate numerical and other data

use information to identify patterns, report trends and draw conclusions

present reasoned explanation for phenomena, patterns and relationships

make predictions and propose hypotheses

apply knowledge, including principles, to novel situations

demonstrate awareness of the limitations of biological theories and models

solve problems

Questions testing the skills in the table above will usually begin with one of the following words: discuss, predict, suggest, calculate or determine. See Section 6 for an explanation of these words.

Look carefully at the skills you need to develop during your course in preparation for Papers 3 and 5.

Skill area You will need to be able to:

AO3 Experimental skills and investigations

plan experiments and investigations

collect, record and present observations, measurements and estimates

analyse and interpret quality of data to reach conclusions

evaluate methods and quality of data and suggest possible improvements

The following table will give you a general idea of the allocation of marks to assessment objectives in the different examination papers – though the balance in each paper may vary slightly.

Assessment objective Weighting (%) Examination papers

AO1 Knowledge with understanding 40 Papers 1, 2 and 4

AO2 Handling information and solving problems 37 Papers 1, 2 and 4

AO3 Experimental skills and investigations 23 Papers 3 and 5

In addition, 15% of the total marks will be awarded for an awareness of the social, economic, environmental and technological implications and applications of biology. These marks will be awarded within the AO1 and AO2 categories.

Section 4: What you need to know



This is in the form of a table, which describes what you may be tested on in the examination. It is divided into the syllabuses for AS and A Level.

How to use the tableThe table is divided into a number of columns.

Topic – this is a main subject area within each syllabus. There are a varying number of topics within each syllabus;

Sub-topic – this column subdivides the main topic into a number of different topics.

You should be able to – this column gives you all the detail that you will be expected to know and understand in relation to each topic. It is arranged in bullet points. Each bullet point is a learning outcome taken from the syllabus. You should read these learning outcomes very carefully as examiners set questions on these. If you know the learning outcomes you will be well prepared for the examinations as you will know what topics you are being tested on.

Examiners can set questions on unfamiliar situations and expect you to apply your knowledge to understanding and analysing them. Do not panic if you have a question on an organism you have not been taught about or something else that is new to you. There will be clues in the question to help you identify the topic that is being tested in the question.

You can use the table throughout your course to check the topic areas you have covered.

You can also use it as a revision aid. When you think you have a good knowledge of a topic, you can place a tick in the checklist column.

The column headed Comments can be used:

• to add further information about the details for each bullet point

• to add learning aids

• to highlight areas of diffi culty/things about which you need to ask your teacher.



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

1 C

ell s

truc

ture

1.1

Th

e m

icro

sco

pe

in

cell

stu

die

s

A

n un

ders

tand

ing

of t

he p

rinci

ples

of

mic

rosc

opy

show

s w

hy li

ght

and

elec

tron

m

icro

scop

es h

ave

been

ess

entia

l in

impr

ovin

g ou

r kn

owle

dge

of c

ells

.

a)

com

pare

the

str

uctu

re o

f ty

pica

l ani

mal

and

pla

nt c

ells

by

mak

ing

tem

pora

ry p

repa

ratio

ns o

f liv

e m

ater

ial a

nd u

sing

ph

otom

icro

grap

hs

b)

calc

ulat

e th

e lin

ear

mag

nifi c

atio

ns o

f dr

awin

gs,

phot

omic

rogr

aphs

and

ele

ctro

n m

icro

grap

hs

c)

use

an e

yepi

ece

grat

icul

e an

d st

age

mic

rom

eter

sca

le

to m

easu

re c

ells

and

be

fam

iliar

with

uni

ts (m

illim

etre

, m

icro

met

re, n

anom

etre

) use

d in

cel

l stu

dies

d)

expl

ain

and

dist

ingu

ish

betw

een

reso

lutio

n an

d m

agni

fi cat

ion,

with

ref

eren

ce t

o lig

ht m

icro

scop

y an

d el

ectr

on m

icro

scop

y

e)

calc

ulat

e ac

tual

siz

es o

f sp

ecim

ens

from

dra

win

gs,

phot

omic

rogr

aphs

and

ele

ctro

n m

icro

grap

hs



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

1 C

ell s

truc

ture

1.2

Cel

ls a

s th

e b

asic

u

nit

s o

f liv

ing

o

rgan

ism

s

Th

e ce

ll is

the

bas

ic

unit

of a

ll liv

ing

orga

nism

s. T

he

inte

rrel

atio

nshi

ps

betw

een

thes

e ce

ll st

ruct

ures

sh

ow h

ow c

ells

fu

nctio

n to

tra

nsfe

r en

ergy

, pro

duce

bi

olog

ical

mol

ecul

es

incl

udin

g pr

otei

ns

and

exch

ange

su

bsta

nces

with

th

eir

surr

ound

ings

.

P

roka

ryot

ic c

ells

an

d eu

kary

otic

ce

lls s

hare

som

e fe

atur

es, b

ut t

he

diff

eren

ces

betw

een

them

illu

stra

te t

he

divi

de b

etw

een

thes

e tw

o ce

ll ty

pes.

a)

desc

ribe

and

inte

rpre

t el

ectr

on m

icro

grap

hs a

nd

draw

ings

of

typi

cal a

nim

al a

nd p

lant

cel

ls a

s se

en w

ith

the

elec

tron

mic

rosc

ope

b)

reco

gnis

e th

e fo

llow

ing

cell

stru

ctur

es a

nd o

utlin

e th

eir

func

tions

:

• ce

ll su

rfac

e m

embr

ane

• nu

cleu

s, n

ucle

ar e

nvel

ope

and

nucl

eolu

s

• ro

ugh

endo

plas

mic

ret

icul

um

• sm

ooth

end

opla

smic

ret

icul

um

• G

olgi

bod

y (G

olgi

app

arat

us o

r G

olgi

com

plex

)

• m

itoch

ondr

ia (i

nclu

ding

sm

all c

ircul

ar D

NA

)

• rib

osom

es (8

0S in

the

cyt

opla

sm a

nd 7

0S in

ch

loro

plas

ts a

nd m

itoch

ondr

ia)

• ly

soso

mes

• ce

ntrio

les

and

mic

rotu

bule

s

• ch

loro

plas

ts (i

nclu

ding

sm

all c

ircul

ar D

NA

)

• ce

ll w

all

• pl

asm

odes

mat

a

• la

rge

perm

anen

t va

cuol

e an

d to

nopl

ast

of p

lant

cel

ls

c)

stat

e th

at A

TP is

pro

duce

d in

mito

chon

dria

and

ch

loro

plas

ts a

nd o

utlin

e th

e ro

le o

f A

TP in

cel

ls

d)

outli

ne k

ey s

truc

tura

l fea

ture

s of

typ

ical

pro

kary

otic

cel

ls

as s

een

in a

typ

ical

bac

teriu

m (i

nclu

ding

: uni

cellu

lar,

1-

5µm

dia

met

er, p

eptid

ogly

can

cell

wal

ls, l

ack

of

orga

nelle

s su

rrou

nded

by

doub

le m

embr

anes

, nak

ed

circ

ular

DN

A,

70S

rib

osom

es)

e)

com

pare

and

con

tras

t th

e st

ruct

ure

of t

ypic

al p

roka

ryot

ic

cells

with

typ

ical

euk

aryo

tic c

ells

(ref

eren

ce t

o m

esos

omes

sho

uld

not

be in

clud

ed)

f)

outli

ne t

he k

ey f

eatu

res

of v

iruse

s as

non

-cel

lula

r st

ruct

ures

(lim

ited

to p

rote

in c

oat

and

DN

A/R

NA

)



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

2 B

iolo

gica

l mol

ecul

es2.

1 T

esti

ng

fo

r b

iolo

gic

al

mo

lecu

les

Te

sts

for

biol

ogic

al

mol

ecul

es c

an b

e us

ed in

a v

arie

ty

of c

onte

xts,

suc

h as

iden

tifyi

ng t

he

cont

ents

of

mix

ture

s of

mol

ecul

es a

nd

follo

win

g th

e ac

tivity

of

dige

stiv

e en

zym

es.

a)

carr

y ou

t te

sts

for

redu

cing

sug

ars

and

non-

redu

cing

su

gars

, the

iodi

ne in

pot

assi

um io

dide

sol

utio

n te

st f

or

star

ch, t

he e

mul

sion

tes

t fo

r lip

ids

and

the

biur

et t

est

for

prot

eins

to

iden

tify

the

cont

ents

of

solu

tions

b)

carr

y ou

t a

sem

i-qua

ntita

tive

Ben

edic

t’s

test

on

a re

duci

ng s

ugar

usi

ng d

ilutio

n, s

tand

ardi

sing

the

tes

t an

d us

ing

the

resu

lts (c

olou

r st

anda

rds

or t

ime

to fi

rst

colo

ur

chan

ge) t

o es

timat

e th

e co

ncen

trat

ion



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

2 B

iolo

gica

l mol

ecul

es2.

2 C

arb

oh

ydra

tes

and

lip

ids

C

arbo

hydr

ates

an

d lip

ids

have

im

port

ant

role

s in

th

e pr

ovis

ion

and

stor

age

of e

nerg

y an

d fo

r a

varie

ty

of o

ther

fun

ctio

ns

such

as

prov

idin

g ba

rrie

rs a

roun

d ce

lls:

the

phos

phol

ipid

bi

laye

r of

all

cell

mem

bran

es a

nd t

he

cellu

lose

cel

l wal

ls

of p

lant

cel

ls.

a)

desc

ribe

the

ring

form

s of

α-g

luco

se a

nd β

-glu

cose

b)

defi n

e th

e te

rms

mon

omer

, pol

ymer

, mac

rom

olec

ule,

m

onos

acch

arid

e, d

isac

char

ide

and

poly

sacc

harid

e

c)

desc

ribe

the

form

atio

n of

a g

lyco

sidi

c bo

nd b

y co

nden

satio

n, w

ith r

efer

ence

bot

h to

pol

ysac

char

ides

an

d to

dis

acch

arid

es, i

nclu

ding

suc

rose

d)

desc

ribe

the

brea

kage

of

glyc

osid

ic b

onds

in

poly

sacc

harid

es a

nd d

isac

char

ides

by

hydr

olys

is, w

ith

refe

renc

e to

the

no

n-re

duci

ng s

ugar

tes

t

e)

desc

ribe

the

mol

ecul

ar s

truc

ture

of

poly

sacc

harid

es

incl

udin

g st

arch

(am

ylos

e an

d am

ylop

ectin

), gl

ycog

en a

nd

cellu

lose

and

rel

ate

thes

e st

ruct

ures

to

thei

r fu

nctio

ns in

liv

ing

orga

nism

s

f)

desc

ribe

the

mol

ecul

ar s

truc

ture

of

a tr

igly

cerid

e w

ith

refe

renc

e to

the

for

mat

ion

of e

ster

bon

ds a

nd r

elat

e th

e st

ruct

ure

of t

rigly

cerid

es t

o th

eir

func

tions

in li

ving

or

gani

sms

g)

desc

ribe

the

stru

ctur

e of

a p

hosp

holip

id a

nd r

elat

e th

e st

ruct

ure

of p

hosp

holip

ids

to t

heir

func

tions

in li

ving

or

gani

sms



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

2 B

iolo

gica

l mol

ecul

es2.

3 P

rote

ins

and

wat

er

A

n un

ders

tand

ing

of p

rote

in s

truc

ture

an

d ho

w it

is r

elat

ed

to f

unct

ion

is c

entr

al

to m

any

aspe

cts

of b

iolo

gy, s

uch

as

enzy

mes

, ant

ibod

ies

and

mus

cle

cont

ract

ion.

G

lobu

lar

and

fi bro

us p

rote

ins

play

impo

rtan

t ro

les

in b

iolo

gica

l pr

oces

ses

such

as

the

tra

nspo

rt o

f ga

ses

and

prov

idin

g su

ppor

t fo

r tis

sues

.

W

ater

is a

spe

cial

m

olec

ule

with

ex

trao

rdin

ary

prop

ertie

s th

at m

ake

life

poss

ible

on

this

pl

anet

150

mill

ion

kilo

met

res

from

the

S

un.

a)

desc

ribe

the

stru

ctur

e of

an

amin

o ac

id a

nd t

he f

orm

atio

n an

d br

eaka

ge o

f a

pept

ide

bond

b)

expl

ain

the

mea

ning

of

the

term

s pr

imar

y st

ruct

ure,

se

cond

ary

stru

ctur

e, t

ertia

ry s

truc

ture

and

qua

tern

ary

stru

ctur

e of

pro

tein

s an

d de

scrib

e th

e ty

pes

of b

ondi

ng

(hyd

roge

n, io

nic,

dis

ulfi d

e an

d hy

drop

hobi

c in

tera

ctio

ns)

that

hol

d th

ese

mol

ecul

es in

sha

pe

c)

desc

ribe

the

mol

ecul

ar s

truc

ture

of

haem

oglo

bin

as a

n ex

ampl

e of

a g

lobu

lar

prot

ein,

and

of

colla

gen

as a

n ex

ampl

e of

a fi

brou

s pr

otei

n an

d re

late

the

se

stru

ctur

es t

o th

eir

func

tions

(The

impo

rtan

ce o

f iro

n in

th

e ha

emog

lobi

n m

olec

ule

shou

ld b

e em

phas

ised

. A

haem

oglo

bin

mol

ecul

e is

com

pose

d of

tw

o al

pha

(α)

chai

ns a

nd t

wo

beta

(β) c

hain

s, a

lthou

gh w

hen

desc

ribin

g th

e ch

ains

the

ter

ms α-

glob

in a

nd β

-glo

bin

may

be

used

. The

re s

houl

d be

a d

istin

ctio

n be

twee

n co

llage

n m

olec

ules

and

col

lage

n fi b

res)

d)

expl

ain

how

hyd

roge

n bo

ndin

g oc

curs

bet

wee

n w

ater

m

olec

ules

and

rel

ate

the

prop

ertie

s of

wat

er t

o its

rol

es

in li

ving

org

anis

ms

(lim

ited

to s

olve

nt a

ctio

n, s

peci

fi c

heat

cap

acity

and

late

nt h

eat

of v

apou

risat

ion)



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

3 En

zym

es3.

1 M

od

e o

f ac

tio

n o

f en

zym

es

Th

ere

are

man

y di

ffer

ent

enzy

mes

, ea

ch o

ne s

peci

fi c t

o a

part

icul

ar r

eact

ion.

Th

is s

peci

fi city

is t

he

key

to u

nder

stan

ding

th

e ef

fi cie

nt

func

tioni

ng o

f ce

lls

and

livin

g or

gani

sms.

a)

expl

ain

that

enz

ymes

are

glo

bula

r pr

otei

ns t

hat

cata

lyse

m

etab

olic

rea

ctio

ns

b)

stat

e th

at e

nzym

es f

unct

ion

insi

de c

ells

(int

race

llula

r en

zym

es) a

nd o

utsi

de c

ells

(ext

race

llula

r en

zym

es)

c)

expl

ain

the

mod

e of

act

ion

of e

nzym

es in

ter

ms

of a

n ac

tive

site

, enz

yme/

subs

trat

e co

mpl

ex, l

ower

ing

of

activ

atio

n en

ergy

and

enz

yme

spec

ifi ci

ty (t

he lo

ck a

nd

key

hypo

thes

is a

nd t

he in

duce

d fi t

hyp

othe

sis

shou

ld b

e in

clud

ed)

d)

inve

stig

ate

the

prog

ress

of

an e

nzym

e-ca

taly

sed

reac

tion

by m

easu

ring

rate

s of

for

mat

ion

of p

rodu

cts

(for

ex

ampl

e, u

sing

cat

alas

e) o

r ra

tes

of d

isap

pear

ance

of

subs

trat

e (f

or e

xam

ple,

usi

ng a

myl

ase)

3 En

zym

es3.

2 Fa

cto

rs t

hat

aff

ect

enzy

me

acti

on

In

vest

igat

ing

the

effe

cts

of f

acto

rs

on e

nzym

e ac

tivity

gi

ves

oppo

rtun

ities

fo

r pl

anni

ng

and

carr

ying

out

ex

perim

ents

un

der

cont

rolle

d co

nditi

ons.

a)

inve

stig

ate

and

expl

ain

the

effe

cts

of t

he f

ollo

win

g fa

ctor

s on

the

rat

e of

enz

yme-

cata

lyse

d re

actio

ns:

• te

mpe

ratu

re

• pH

(usi

ng b

uffe

r so

lutio

ns)

• en

zym

e co

ncen

trat

ion

• su

bstr

ate

conc

entr

atio

n

• in

hibi

tor

conc

entr

atio

n

b)

expl

ain

that

the

max

imum

rat

e of

rea

ctio

n (V

max

) is

used

to

der

ive

the

Mic

hael

is-M

ente

n co

nsta

nt (K

m) w

hich

is

used

to

com

pare

the

affi

nity

of

diff

eren

t en

zym

es f

or

thei

r su

bstr

ates

c)

expl

ain

the

effe

cts

of r

ever

sibl

e in

hibi

tors

, bot

h co

mpe

titiv

e an

d no

n-co

mpe

titiv

e, o

n th

e ra

te o

f en

zym

e ac

tivity

d)

inve

stig

ate

and

expl

ain

the

effe

ct o

f im

mob

ilisi

ng a

n en

zym

e in

alg

inat

e on

its

activ

ity a

s co

mpa

red

with

its

activ

ity w

hen

free

in s

olut

ion



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

4 C

ell m

embr

anes

and

tr

ansp

ort

4.1

Flu

id m

osa

ic

mem

bra

nes

Th

e st

ruct

ure

of c

ell

surf

ace

mem

bran

es

allo

ws

mov

emen

t of

sub

stan

ces

betw

een

cells

and

th

eir

surr

ound

ings

an

d al

low

s ce

lls t

o co

mm

unic

ate

with

ea

ch o

ther

by

cell

sign

allin

g.

a)

desc

ribe

and

expl

ain

the

fl uid

mos

aic

mod

el o

f m

embr

ane

stru

ctur

e, in

clud

ing

an o

utlin

e of

the

rol

es

of p

hosp

holip

ids,

cho

lest

erol

, gly

colip

ids,

pro

tein

s an

d gl

ycop

rote

ins

b)

outli

ne t

he r

oles

of

cell

surf

ace

mem

bran

es in

clud

ing

refe

renc

es t

o ca

rrie

r pr

otei

ns, c

hann

el p

rote

ins,

cel

l su

rfac

e re

cept

ors

and

cell

surf

ace

antig

ens

c)

outli

ne t

he p

roce

ss o

f ce

ll si

gnal

ling

invo

lvin

g th

e re

leas

e of

che

mic

als

that

com

bine

with

cel

l sur

face

rec

epto

rs o

n ta

rget

cel

ls, l

eadi

ng t

o sp

ecifi

c re

spon

ses



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

4 C

ell m

embr

anes

and

tr

ansp

ort

4.2

Mo

vem

ent

of

sub

stan

ces

into

an

d o

ut

of

cells

Th

e fl u

id m

osai

c m

odel

allo

ws

an

unde

rsta

ndin

g of

ho

w s

ubst

ance

s en

ter

and

exit

cells

by

a va

riety

of

diff

eren

t m

echa

nism

s.

In

vest

igat

ing

the

effe

ct o

f in

crea

sing

th

e si

ze o

f m

odel

ce

lls a

llow

s an

un

ders

tand

ing

of

the

cons

trai

nts

of

obta

inin

g re

sour

ces

acro

ss t

he c

ell

surf

ace

and

mov

ing

subs

tanc

es o

ut o

f ce

lls.

a)

desc

ribe

and

expl

ain

the

proc

esse

s of

diff

usio

n,

faci

litat

ed d

iffus

ion,

osm

osis

, act

ive

tran

spor

t,

endo

cyto

sis

and

exoc

ytos

is (n

o ca

lcul

atio

ns in

volv

ing

wat

er p

oten

tial w

ill b

e se

t)

b)

inve

stig

ate

sim

ple

diff

usio

n us

ing

plan

t tis

sue

and

non-

livin

g m

ater

ials

, suc

h as

glu

cose

sol

utio

ns, V

iski

ng t

ubin

g an

d ag

ar

c)

calc

ulat

e su

rfac

e ar

eas

and

volu

mes

of

sim

ple

shap

es

(e.g

. cub

es) t

o ill

ustr

ate

the

prin

cipl

e th

at s

urfa

ce a

rea

to

volu

me

ratio

s de

crea

se w

ith in

crea

sing

siz

e

d)

inve

stig

ate

the

effe

ct o

f ch

angi

ng s

urfa

ce a

rea

to v

olum

e ra

tio o

n di

ffus

ion

usin

g ag

ar b

lock

s of

diff

eren

t si

zes

e)

inve

stig

ate

the

effe

cts

of im

mer

sing

pla

nt t

issu

es in

so

lutio

ns o

f di

ffer

ent

wat

er p

oten

tial,

usin

g th

e re

sults

to

estim

ate

the

wat

er p

oten

tial o

f th

e tis

sues

f)

expl

ain

the

mov

emen

t of

wat

er b

etw

een

cells

and

so

lutio

ns w

ith d

iffer

ent

wat

er p

oten

tials

and

exp

lain

the

di

ffer

ent

effe

cts

on p

lant

and

ani

mal

cel

ls



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

5 Th

e m

itotic

cel

l cyc

le5.

1 R

eplic

atio

n a

nd

d

ivis

ion

of

nu

clei

an

d c

ells

D

urin

g th

e m

itotic

ce

ll cy

cle,

DN

A

is r

eplic

ated

and

pa

ssed

to

daug

hter

ce

lls.

S

tem

cel

ls in

bon

e m

arro

w a

nd t

he

skin

con

tinua

lly

divi

de b

y m

itosi

s to

pr

ovid

e a

cont

inuo

us

supp

ly o

f ce

lls t

hat

diff

eren

tiate

into

bl

ood

and

skin

cel

ls.

a)

desc

ribe

the

stru

ctur

e of

a c

hrom

osom

e, li

mite

d to

DN

A,

hist

one

prot

eins

, chr

omat

ids,

cen

trom

ere

and

telo

mer

es

b)

expl

ain

the

impo

rtan

ce o

f m

itosi

s in

the

pro

duct

ion

of

gene

tical

ly id

entic

al c

ells

, gro

wth

, cel

l rep

lace

men

t,

repa

ir of

tis

sues

and

ase

xual

rep

rodu

ctio

n

c)

outli

ne t

he c

ell c

ycle

, inc

ludi

ng in

terp

hase

(gro

wth

and

D

NA

rep

licat

ion)

, mito

sis

and

cyto

kine

sis

d)

outli

ne t

he s

igni

fi can

ce o

f te

lom

eres

in p

erm

ittin

g co

ntin

ued

repl

icat

ion

and

prev

entin

g th

e lo

ss o

f ge

nes

e)

outli

ne t

he s

igni

fi can

ce o

f m

itosi

s in

cel

l rep

lace

men

t an

d tis

sue

repa

ir by

ste

m c

ells

and

sta

te t

hat

unco

ntro

lled

cell

divi

sion

can

res

ult

in t

he f

orm

atio

n of

a t

umou

r

5 Th

e m

itotic

cel

l cyc

le5.

2 C

hro

mo

som

e b

ehav

iou

r in

m

ito

sis

Th

e ev

ents

tha

t oc

cur

durin

g m

itosi

s ca

n be

fol

low

ed

by u

sing

a li

ght

mic

rosc

ope.

a)

desc

ribe,

with

the

aid

of

phot

omic

rogr

aphs

and

dia

gram

s,

the

beha

viou

r of

chr

omos

omes

in p

lant

and

ani

mal

cel

ls

durin

g th

e m

itotic

cel

l cyc

le a

nd t

he a

ssoc

iate

d be

havi

our

of t

he n

ucle

ar e

nvel

ope,

cel

l sur

face

mem

bran

e an

d th

e sp

indl

e (n

ames

of

the

mai

n st

ages

of

mito

sis

are

expe

cted

)

b)

obse

rve

and

draw

the

mito

tic s

tage

s vi

sibl

e in

tem

pora

ry

root

tip

squ

ash

prep

arat

ions

and

in p

repa

red

slid

es o

f ro

ot t

ips

of s

peci

es s

uch

as t

hose

of

Vici

a fa

ba a

nd

Alli

um c

epa



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

6 N

ucle

ic a

cids

and

pr

otei

n sy

nthe

sis

6.1

Str

uct

ure

an

d

rep

licat

ion

of

DN

A

U

nder

stan

ding

th

e st

ruct

ure

of

nucl

eic

acid

s al

low

s an

und

erst

andi

ng

of t

heir

role

in

the

stor

age

of

gene

tic in

form

atio

n an

d ho

w t

hat

info

rmat

ion

is u

sed

in t

he s

ynth

esis

of

prot

eins

.

a)

desc

ribe

the

stru

ctur

e of

nuc

leot

ides

, inc

ludi

ng t

he

phos

phor

ylat

ed n

ucle

otid

e A

TP (s

truc

tura

l for

mul

ae a

re

not

requ

ired)

b)

desc

ribe

the

stru

ctur

e of

RN

A a

nd D

NA

and

exp

lain

the

im

port

ance

of

base

pai

ring

and

the

diff

eren

t hy

drog

en

bond

ing

betw

een

base

s (in

clud

e re

fere

nce

to a

deni

ne

and

guan

ine

as p

urin

es a

nd t

o cy

tosi

ne, t

hym

ine

and

urac

il as

pyr

imid

ines

. Str

uctu

ral f

orm

ulae

for

bas

es a

re

not

requ

ired

but

the

reco

gniti

on t

hat

purin

es h

ave

a do

uble

rin

g st

ruct

ure

and

pyrim

idin

es h

ave

a si

ngle

rin

g st

ruct

ure

shou

ld b

e in

clud

ed)

c)

desc

ribe

the

sem

i-con

serv

ativ

e re

plic

atio

n of

DN

A d

urin

g in

terp

hase

6 N

ucle

ic a

cids

and

pr

otei

n sy

nthe

sis

6.2

Pro

tein

syn

thes

is

Th

e ge

netic

cod

e sp

ecifi

es t

he a

min

o ac

ids

that

are

as

sem

bled

to

mak

e po

lype

ptid

es. T

he

way

tha

t D

NA

cod

es

for

poly

pept

ides

is

cen

tral

to

our

unde

rsta

ndin

g of

how

cel

ls a

nd

orga

nism

s fu

nctio

n.

a)

stat

e th

at a

pol

ypep

tide

is c

oded

for

by

a ge

ne a

nd t

hat

a ge

ne is

a s

eque

nce

of n

ucle

otid

es t

hat

form

s pa

rt o

f a

DN

A m

olec

ule

b)

stat

e th

at a

gen

e m

utat

ion

is a

cha

nge

in t

he s

eque

nce

of n

ucle

otid

es t

hat

may

res

ult

in a

n al

tere

d po

lype

ptid

e

c)

desc

ribe

the

way

in w

hich

the

nuc

leot

ide

sequ

ence

co

des

for

the

amin

o ac

id s

eque

nce

in a

pol

ypep

tide

with

re

fere

nce

to t

he n

ucle

otid

e se

quen

ce f

or H

bA (n

orm

al)

and

HbS (s

ickl

e ce

ll) a

llele

s of

the

gen

e fo

r th

e β-

glob

in

poly

pept

ide

d)

desc

ribe

how

the

info

rmat

ion

in D

NA

is u

sed

durin

g tr

ansc

riptio

n an

d tr

ansl

atio

n to

con

stru

ct p

olyp

eptid

es,

incl

udin

g th

e ro

le o

f m

esse

nger

RN

A (m

RN

A),

tran

sfer

R

NA

(tR

NA

) and

the

rib

osom

es



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

7 Tr

ansp

ort

in p

lant

s7.

1 S

tru

ctu

re o

f tr

ansp

ort

tis

sues

P

lant

s ha

ve t

wo

tran

spor

t tis

sues

: xy

lem

and

phl

oem

.

a)

draw

and

labe

l fro

m p

repa

red

slid

es p

lan

diag

ram

s of

tra

nsve

rse

sect

ions

of

stem

s, r

oots

and

leav

es o

f he

rbac

eous

dic

otyl

edon

ous

plan

ts u

sing

an

eyep

iece

gr

atic

ule

to s

how

tis

sues

in c

orre

ct p

ropo

rtio

ns (s

ee 1

.1c)

b)

draw

and

labe

l fro

m p

repa

red

slid

es t

he c

ells

in

the

diff

eren

t tis

sues

in r

oots

, ste

ms

and

leav

es o

f he

rbac

eous

dic

otyl

edon

ous

plan

ts u

sing

tra

nsve

rse

and

long

itudi

nal s

ectio

ns

c)

draw

and

labe

l fro

m p

repa

red

slid

es t

he s

truc

ture

of

xyle

m v

esse

l ele

men

ts, p

hloe

m s

ieve

tub

e el

emen

ts a

nd

com

pani

on c

ells

and

be

able

to

reco

gnis

e th

ese

usin

g th

e lig

ht m

icro

scop

e

d)

rela

te t

he s

truc

ture

of

xyle

m v

esse

l ele

men

ts, p

hloe

m

siev

e tu

be e

lem

ents

and

com

pani

on c

ells

to

thei

r fu

nctio

ns



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

7 Tr

ansp

ort

in p

lant

s7.

2 T

ran

spo

rt

mec

han

ism

s

M

ovem

ent

of x

ylem

sa

p an

d ph

loem

sap

is

by

mas

s fl o

w.

Mov

emen

t in

the

xy

lem

is p

assi

ve

as it

is d

riven

by

evap

orat

ion

from

th

e le

aves

; pla

nts

use

ener

gy t

o m

ove

subs

tanc

es in

the

ph

loem

.

X

ylem

sap

mov

es in

on

e di

rect

ion

from

th

e ro

ots

to t

he

rest

of

the

plan

t.

The

phlo

em s

ap

in a

phl

oem

sie

ve

tube

mov

es in

one

di

rect

ion

from

the

lo

catio

n w

here

it is

m

ade

to t

he lo

catio

n w

here

it is

use

d or

st

ored

. At

any

one

time

phlo

em s

ap

can

be m

ovin

g in

di

ffer

ent

dire

ctio

ns

in d

iffer

ent

siev

e tu

bes.

a)

expl

ain

the

mov

emen

t of

wat

er b

etw

een

plan

t ce

lls,

and

betw

een

them

and

the

ir en

viro

nmen

t, in

ter

ms

of

wat

er p

oten

tial (

see

4.2.

No

calc

ulat

ions

invo

lvin

g w

ater

po

tent

ial w

ill b

e se

t)

b)

expl

ain

how

hyd

roge

n bo

ndin

g of

wat

er m

olec

ules

is

invo

lved

with

mov

emen

t in

the

xyl

em b

y co

hesi

on-

tens

ion

in t

rans

pira

tion

pull

and

adhe

sion

to

cellu

lose

cel

l w

alls

c)

desc

ribe

the

path

way

s an

d ex

plai

n th

e m

echa

nism

s by

w

hich

wat

er a

nd m

iner

al io

ns a

re t

rans

port

ed f

rom

soi

l to

xyl

em a

nd f

rom

roo

ts t

o le

aves

(inc

lude

ref

eren

ce

to t

he s

ympl

astic

pat

hway

and

apo

plas

tic p

athw

ay a

nd

Cas

paria

n st

rip)

d)

defi n

e th

e te

rm t

rans

pira

tion

and

expl

ain

that

it is

an

inev

itabl

e co

nseq

uenc

e of

gas

exc

hang

e in

pla

nts

e)

inve

stig

ate

expe

rimen

tally

and

exp

lain

the

fac

tors

tha

t af

fect

tra

nspi

ratio

n ra

te u

sing

sim

ple

poto

met

ers,

leaf

im

pres

sion

s, e

pide

rmal

pee

ls, a

nd g

rids

for

dete

rmin

ing

surf

ace

area

f)

mak

e an

nota

ted

draw

ings

, usi

ng p

repa

red

slid

es o

f cr

oss-

sect

ions

, to

show

how

leav

es o

f xe

roph

ytic

pla

nts

are

adap

ted

to r

educ

e w

ater

loss

by

tran

spira

tion

g)

stat

e th

at a

ssim

ilate

s, s

uch

as s

ucro

se a

nd a

min

o ac

ids,

m

ove

betw

een

sour

ces

(e.g

. lea

ves

and

stor

age

orga

ns)

and

sink

s (e

.g. b

uds,

fl ow

ers,

fru

its, r

oots

and

sto

rage

or

gans

) in

phlo

em s

ieve

tub

es

h)

expl

ain

how

suc

rose

is lo

aded

into

phl

oem

sie

ve t

ubes

by

com

pani

on c

ells

usi

ng p

roto

n pu

mpi

ng a

nd t

he c

o-tr

ansp

orte

r m

echa

nism

in t

heir

cell

surf

ace

mem

bran

es

i) ex

plai

n m

ass

fl ow

in p

hloe

m s

ap d

own

a hy

dros

tatic

pr

essu

re g

radi

ent

from

sou

rce

to s

ink



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

8 Tr

ansp

ort

in

mam

mal

s8.

1 T

he

circ

ula

tory

sy

stem

Th

e m

amm

alia

n ci

rcul

ator

y sy

stem

co

nsis

ts o

f a

pum

p,

man

y bl

ood

vess

els

and

bloo

d, w

hich

is

a s

uspe

nsio

n of

re

d bl

ood

cells

and

w

hite

blo

od c

ells

in

plas

ma.

a)

stat

e th

at t

he m

amm

alia

n ci

rcul

ator

y sy

stem

is a

clo

sed

doub

le c

ircul

atio

n co

nsis

ting

of a

hea

rt, b

lood

ves

sels

an

d bl

ood

b)

obse

rve

and

mak

e pl

an d

iagr

ams

of t

he s

truc

ture

of

arte

ries,

vei

ns a

nd c

apill

arie

s us

ing

prep

ared

slid

es

and

be a

ble

to r

ecog

nise

the

se v

esse

ls u

sing

the

ligh

t m

icro

scop

e

c)

expl

ain

the

rela

tions

hip

betw

een

the

stru

ctur

e an

d fu

nctio

n of

art

erie

s, v

eins

and

cap

illar

ies

d)

obse

rve

and

draw

the

str

uctu

re o

f re

d bl

ood

cells

, m

onoc

ytes

, neu

trop

hils

and

lym

phoc

ytes

usi

ng p

repa

red

slid

es a

nd p

hoto

mic

rogr

aphs

e)

stat

e an

d ex

plai

n th

e di

ffer

ence

s be

twee

n bl

ood,

tis

sue

fl uid

and

lym

ph

f)

desc

ribe

the

role

of

haem

oglo

bin

in c

arry

ing

oxyg

en a

nd

carb

on d

ioxi

de w

ith r

efer

ence

to

the

role

of

carb

onic

an

hydr

ase,

the

for

mat

ion

of h

aem

oglo

bini

c ac

id a

nd

carb

amin

ohae

mog

lobi

n (d

etai

ls o

f th

e ch

lorid

e sh

ift a

re

not

requ

ired)

g)

desc

ribe

and

expl

ain

the

sign

ifi ca

nce

of t

he o

xyge

n di

ssoc

iatio

n cu

rves

of

adul

t ox

yhae

mog

lobi

n at

diff

eren

t ca

rbon

dio

xide

con

cent

ratio

ns (t

he B

ohr

effe

ct)

h)

desc

ribe

and

expl

ain

the

sign

ifi ca

nce

of t

he in

crea

se in

th

e re

d bl

ood

cell

coun

t of

hum

ans

at h

igh

altit

ude



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

8 Tr

ansp

ort

in

mam

mal

s8.

2 T

he

hea

rt

Th

e m

amm

alia

n he

art

is a

dou

ble

pum

p: t

he r

ight

sid

e pu

mps

blo

od a

t lo

w p

ress

ure

to t

he

lung

s an

d th

e le

ft

side

pum

ps b

lood

at

high

pre

ssur

e to

the

re

st o

f th

e bo

dy.

a)

desc

ribe

the

exte

rnal

and

inte

rnal

str

uctu

re o

f th

e m

amm

alia

n he

art

b)

expl

ain

the

diff

eren

ces

in t

he t

hick

ness

of

the

wal

ls o

f th

e di

ffer

ent

cham

bers

in t

erm

s of

the

ir fu

nctio

ns w

ith

refe

renc

e to

res

ista

nce

to fl

ow

c)

desc

ribe

the

card

iac

cycl

e (in

clud

ing

bloo

d pr

essu

re

chan

ges

durin

g sy

stol

e an

d di

asto

le)

d)

expl

ain

how

hea

rt a

ctio

n is

initi

ated

and

con

trol

led

(ref

eren

ce s

houl

d be

mad

e to

the

sin

oatr

ial n

ode,

the

at

riove

ntric

ular

nod

e an

d th

e P

urky

ne t

issu

e, b

ut n

ot t

o ne

rvou

s an

d ho

rmon

al c

ontr

ol)

9 G

as e

xcha

nge

and

smok

ing

9.1

Th

e g

as e

xch

ang

e sy

stem

Th

e ga

s ex

chan

ge

surf

ace

in t

he lu

ngs

is e

xten

sive

, ver

y th

in, w

ell s

uppl

ied

with

blo

od a

nd

wel

l ven

tilat

ed.

The

trac

hea

and

bron

chi p

rovi

de li

ttle

re

sist

ance

to

the

mov

emen

t of

air

to

and

from

the

alv

eoli.

a)

desc

ribe

the

gros

s st

ruct

ure

of t

he h

uman

gas

exc

hang

e sy

stem

b)

obse

rve

and

draw

pla

n di

agra

ms

of t

he s

truc

ture

of

the

wal

ls o

f th

e tr

ache

a, b

ronc

hi, b

ronc

hiol

es a

nd a

lveo

li in

dica

ting

the

dist

ribut

ion

of c

artil

age,

cili

ated

epi

thel

ium

, go

blet

cel

ls, s

moo

th m

uscl

e, s

quam

ous

epith

eliu

m a

nd

bloo

d ve

ssel

s

c)

desc

ribe

the

func

tions

of

cart

ilage

, cili

a, g

oble

t ce

lls,

muc

ous

glan

ds, s

moo

th m

uscl

e an

d el

astic

fi br

es a

nd

reco

gnis

e th

ese

cells

and

tis

sues

in p

repa

red

slid

es,

phot

omic

rogr

aphs

and

ele

ctro

n m

icro

grap

hs o

f th

e ga

s ex

chan

ge s

yste

m

d)

desc

ribe

the

proc

ess

of g

as e

xcha

nge

betw

een

air

in t

he

alve

oli a

nd t

he b

lood



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

9 G

as e

xcha

nge

and

smok

ing

9.2

Sm

oki

ng

S

mok

ing

is o

ne o

f th

e m

ajor

avo

idab

le

risk

fact

ors

of

chro

nic,

life

-th

reat

enin

g di

seas

es

of t

he g

as e

xcha

nge

and

circ

ulat

ory

syst

ems.

a)

desc

ribe

the

effe

cts

of t

ar a

nd c

arci

noge

ns in

tob

acco

sm

oke

on t

he g

as e

xcha

nge

syst

em w

ith r

efer

ence

to

lung

can

cer

and

chro

nic

obst

ruct

ive

pulm

onar

y di

seas

e (C

OP

D)

b)

desc

ribe

the

shor

t-te

rm e

ffec

ts o

f ni

cotin

e an

d ca

rbon

m

onox

ide

on t

he c

ardi

ovas

cula

r sy

stem

10 In

fect

ious

dis

ease

10.1

In

fect

iou

s d

isea

ses

W

hile

man

y in

fect

ious

di

seas

es h

ave

been

suc

cess

fully

co

ntro

lled

in s

ome

part

s of

the

wor

ld,

man

y pe

ople

w

orld

wid

e ar

e st

ill

at r

isk

of t

hese

di

seas

es.

a)

defi n

e th

e te

rm d

isea

se a

nd e

xpla

in t

he d

iffer

ence

be

twee

n an

infe

ctio

us d

isea

se a

nd a

non

-infe

ctio

us

dise

ase

(lim

ited

to s

ickl

e ce

ll an

aem

ia a

nd lu

ng c

ance

r)

b)

stat

e th

e na

me

and

type

of

caus

ativ

e or

gani

sm

(pat

hoge

n) o

f ea

ch o

f th

e fo

llow

ing

dise

ases

: cho

lera

, m

alar

ia, t

uber

culo

sis

(TB

), H

IV/A

IDS

, sm

allp

ox a

nd

mea

sles

(det

aile

d kn

owle

dge

of s

truc

ture

is n

ot r

equi

red.

Fo

r sm

allp

ox (V

ario

la) a

nd m

easl

es (M

orbi

llivi

rus)

onl

y th

e na

me

of g

enus

is n

eede

d)

c)

expl

ain

how

cho

lera

, mea

sles

, mal

aria

, TB

and

HIV

/AID

S

are

tran

smitt

ed

d)

disc

uss

the

biol

ogic

al, s

ocia

l and

eco

nom

ic f

acto

rs t

hat

need

to

be c

onsi

dere

d in

the

pre

vent

ion

and

cont

rol o

f ch

oler

a, m

easl

es, m

alar

ia, T

B a

nd H

IV/A

IDS

(a d

etai

led

stud

y of

the

life

cyc

le o

f th

e m

alar

ial p

aras

ite is

not

re

quire

d)

e)

disc

uss

the

fact

ors

that

infl u

ence

the

glo

bal p

atte

rns

of

dist

ribut

ion

of m

alar

ia, T

B a

nd H

IV/A

IDS

and

ass

ess

the

impo

rtan

ce o

f th

ese

dise

ases

wor

ldw

ide



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

10 In

fect

ious

dis

ease

10.2

An

tib

ioti

cs

Th

e ‘a

ge o

f an

tibio

tics’

beg

an

in t

he 1

940s

with

th

e av

aila

bilit

y of

pe

nici

llin.

With

an

incr

ease

in a

ntib

iotic

re

sist

ance

is t

his

age

abou

t to

com

e to

an

end?

a)

outli

ne h

ow p

enic

illin

act

s on

bac

teria

and

why

ant

ibio

tics

do n

ot a

ffec

t vi

ruse

s

b)

expl

ain

in o

utlin

e ho

w b

acte

ria b

ecom

e re

sist

ant

to

antib

iotic

s w

ith r

efer

ence

to

mut

atio

n an

d se

lect

ion

c)

disc

uss

the

cons

eque

nces

of

antib

iotic

res

ista

nce

and

the

step

s th

at c

an b

e ta

ken

to r

educ

e its

impa

ct

11 Im

mun

ity11

.1 T

he

imm

un

e sy

stem

Th

e im

mun

e sy

stem

ha

s no

n-sp

ecifi

c an

d sp

ecifi

c re

spon

ses

to p

atho

gens

. A

uto-

imm

une

dise

ases

are

the

re

sult

of f

ailu

res

in t

he s

yste

m t

o di

stin

guis

h be

twee

n se

lf an

d no

n-se

lf.

a)

stat

e th

at p

hago

cyte

s (m

acro

phag

es a

nd n

eutr

ophi

ls)

have

the

ir or

igin

in b

one

mar

row

and

des

crib

e th

eir

mod

e of

act

ion

b)

desc

ribe

the

mod

es o

f ac

tion

of B

-lym

phoc

ytes

and

T-

lym

phoc

ytes

c)

desc

ribe

and

expl

ain

the

sign

ifi ca

nce

of t

he in

crea

se

in w

hite

blo

od c

ell c

ount

in h

uman

s w

ith in

fect

ious

di

seas

es a

nd le

ukae

mia

s

d)

expl

ain

the

mea

ning

of

the

term

imm

une

resp

onse

, m

akin

g re

fere

nce

to t

he t

erm

s an

tigen

, sel

f an

d no

n-se

lf

e)

expl

ain

the

role

of

mem

ory

cells

in lo

ng-t

erm

imm

unity

f)

expl

ain,

with

ref

eren

ce t

o m

yast

heni

a gr

avis

, tha

t th

e im

mun

e sy

stem

som

etim

es f

ails

to

dist

ingu

ish

betw

een

self

and

non-

self



AS

Lev

el m

ater

ial

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

11 Im

mun

ity11

.2 A

nti

bo

die

s an

d

vacc

inat

ion

A

ctiv

e an

d pa

ssiv

e im

mun

isat

ions

are

ef

fect

ive

way

s to

tr

eat

and

prev

ent

infe

ctio

us d

isea

ses.

S

mal

lpox

has

bee

n er

adic

ated

; oth

er

dise

ases

may

soo

n fo

llow

, but

vac

cine

de

velo

pmen

t ha

s pr

oved

mor

e di

ffi c

ult

for

dise

ases

suc

h as

m

alar

ia.

a)

rela

te t

he m

olec

ular

str

uctu

re o

f an

tibod

ies

to t

heir

func

tions

(see

2.3

b)

b)

outli

ne t

he h

ybrid

oma

met

hod

for

the

prod

uctio

n of

m

onoc

lona

l ant

ibod

ies

c)

outli

ne t

he u

se o

f m

onoc

lona

l ant

ibod

ies

in t

he d

iagn

osis

of

dis

ease

and

in t

he t

reat

men

t of

dis

ease

d)

dist

ingu

ish

betw

een

activ

e an

d pa

ssiv

e, n

atur

al a

nd

artifi

cia

l im

mun

ity a

nd e

xpla

in h

ow v

acci

natio

n ca

n co

ntro

l dis

ease

e)

disc

uss

the

reas

ons

why

vac

cina

tion

prog

ram

mes

hav

e er

adic

ated

sm

allp

ox, b

ut n

ot m

easl

es, t

uber

culo

sis

(TB

), m

alar

ia o

r ch

oler

a



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

12 E

nerg

y an

d re

spira

tion

12.1

En

erg

y

A

TP is

the

uni

vers

al

ener

gy c

urre

ncy

as it

pro

vide

s th

e im

med

iate

sou

rce

of e

nerg

y fo

r ce

llula

r pr

oces

ses.

a)

outli

ne t

he n

eed

for

ener

gy in

livi

ng o

rgan

ism

s, a

s ill

ustr

ated

by

anab

olic

rea

ctio

ns, s

uch

as D

NA

rep

licat

ion

and

prot

ein

synt

hesi

s, a

ctiv

e tr

ansp

ort,

mov

emen

t an

d th

e m

aint

enan

ce o

f bo

dy t

empe

ratu

re

b)

desc

ribe

the

feat

ures

of

ATP

tha

t m

ake

it su

itabl

e as

the

un

iver

sal e

nerg

y cu

rren

cy

c)

expl

ain

that

ATP

is s

ynth

esis

ed in

sub

stra

te-li

nked

re

actio

ns in

gly

coly

sis

and

in t

he K

rebs

cyc

le

d)

outli

ne t

he r

oles

of

the

coen

zym

es N

AD

, FA

D a

nd

coen

zym

e A

in r

espi

ratio

n

e)

expl

ain

that

the

syn

thes

is o

f A

TP is

ass

ocia

ted

with

th

e el

ectr

on t

rans

port

cha

in o

n th

e m

embr

anes

of

mito

chon

dria

and

chl

orop

last

s (s

ee 1

2.2g

)

f)

expl

ain

the

rela

tive

ener

gy v

alue

s of

car

bohy

drat

e, li

pid

and

prot

ein

as r

espi

rato

ry s

ubst

rate

s an

d ex

plai

n w

hy

lipid

s ar

e pa

rtic

ular

ly e

nerg

y-ric

h

g)

defi n

e th

e te

rm r

espi

rato

ry q

uotie

nt (R

Q) a

nd d

eter

min

e R

Qs

from

equ

atio

ns f

or r

espi

ratio

n

h)

carr

y ou

t in

vest

igat

ions

, usi

ng s

impl

e re

spiro

met

ers,

to

det

erm

ine

the

RQ

of

germ

inat

ing

seed

s or

sm

all

inve

rteb

rate

s (e

.g. b

low

fl y la

rvae

)

12 E

nerg

y an

d re

spira

tion

12.2

Res

pir

atio

n

R

espi

ratio

n is

the

pr

oces

s w

here

by

ener

gy f

rom

co

mpl

ex o

rgan

ic

mol

ecul

es is

tr

ansf

erre

d to

ATP

.

a)

list

the

four

sta

ges

in a

erob

ic r

espi

ratio

n (g

lyco

lysi

s, li

nk

reac

tion,

Kre

bs c

ycle

and

oxi

dativ

e ph

osph

oryl

atio

n) a

nd

stat

e w

here

eac

h oc

curs

in e

ukar

yotic

cel

ls

b)

outli

ne g

lyco

lysi

s as

pho

spho

ryla

tion

of g

luco

se a

nd t

he

subs

eque

nt s

plitt

ing

of f

ruct

ose

1,6-

bisp

hosp

hate

(6C

) in

to t

wo

trio

se p

hosp

hate

mol

ecul

es, w

hich

are

the

n fu

rthe

r ox

idis

ed t

o py

ruva

te w

ith a

sm

all y

ield

of

ATP

and

re

duce

d N

AD

c)

expl

ain

that

, whe

n ox

ygen

is a

vaila

ble,

pyr

uvat

e is

co

nver

ted

into

ace

tyl (

2C) c

oenz

yme

A in

the

link

rea

ctio

n



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

12 E

nerg

y an

d re

spira

tion

Th

is p

roce

ss o

f A

TP

synt

hesi

s us

ing

the

ener

gy in

pro

ton

grad

ient

s is

com

mon

to

bot

h re

spira

tion

and

phot

osyn

thes

is.

d)

outli

ne t

he K

rebs

cyc

le, e

xpla

inin

g th

at o

xalo

acet

ate

(a

4C c

ompo

und)

act

s as

an

acce

ptor

of

the

2C f

ragm

ent

from

ace

tyl c

oenz

yme

A t

o fo

rm c

itrat

e (a

6C

com

poun

d),

whi

ch is

rec

onve

rted

to

oxal

oace

tate

in a

ser

ies

of s

mal

l st

eps

e)

expl

ain

that

rea

ctio

ns in

the

Kre

bs c

ycle

invo

lve

deca

rbox

ylat

ion

and

dehy

drog

enat

ion

and

the

redu

ctio

n of

NA

D a

nd F

AD

f)

outli

ne t

he p

roce

ss o

f ox

idat

ive

phos

phor

ylat

ion

incl

udin

g th

e ro

le o

f ox

ygen

as

the

fi nal

ele

ctro

n ac

cept

or (n

o de

tails

of

the

carr

iers

are

req

uire

d)

g)

expl

ain

that

dur

ing

oxid

ativ

e ph

osph

oryl

atio

n:

• en

erge

tic e

lect

rons

rel

ease

ene

rgy

as t

hey

pass

th

roug

h th

e el

ectr

on t

rans

port

sys

tem

• th

e re

leas

ed e

nerg

y is

use

d to

tra

nsfe

r pr

oton

s ac

ross

the

inne

r m

itoch

ondr

ial m

embr

ane

• pr

oton

s re

turn

to

the

mito

chon

dria

l mat

rix b

y fa

cilit

ated

diff

usio

n th

roug

h A

TP s

ynth

ase

prov

idin

g en

ergy

for

ATP

syn

thes

is (d

etai

ls o

f A

TP s

ynth

ase

are

not

requ

ired)

h)

carr

y ou

t in

vest

igat

ions

to

dete

rmin

e th

e ef

fect

of

fact

ors

such

as

tem

pera

ture

and

sub

stra

te c

once

ntra

tion

on t

he

rate

of

resp

iratio

n of

yea

st u

sing

a r

edox

indi

cato

r (e

.g.

DC

PIP

or

met

hyle

ne b

lue)

i) de

scrib

e th

e re

latio

nshi

p be

twee

n st

ruct

ure

and

func

tion

of t

he m

itoch

ondr

ion

usin

g di

agra

ms

and

elec

tron

m

icro

grap

hs



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

12 E

nerg

y an

d re

spira

tion

S

ome

orga

nism

s an

d so

me

tissu

es

are

able

to

resp

ire

in b

oth

aero

bic

and

anae

robi

c co

nditi

ons.

W

hen

yeas

t an

d pl

ants

res

pire

un

der

anae

robi

c co

nditi

ons,

the

y pr

oduc

e et

hano

l an

d ca

rbon

dio

xide

as

end

-pro

duct

s;

mam

mal

ian

mus

cle

tissu

e pr

oduc

es

lact

ate

whe

n ox

ygen

is

in s

hort

sup

ply.

j) di

stin

guis

h be

twee

n re

spira

tion

in a

erob

ic a

nd a

naer

obic

co

nditi

ons

in m

amm

alia

n tis

sue

and

in y

east

cel

ls,

cont

rast

ing

the

rela

tive

ener

gy r

elea

sed

by e

ach

(a

deta

iled

acco

unt

of t

he t

otal

yie

ld o

f A

TP f

rom

the

ae

robi

c re

spira

tion

of g

luco

se is

not

req

uire

d)

k)

expl

ain

the

prod

uctio

n of

a s

mal

l yie

ld o

f A

TP f

rom

re

spira

tion

in a

naer

obic

con

ditio

ns in

yea

st a

nd in

m

amm

alia

n m

uscl

e tis

sue,

incl

udin

g th

e co

ncep

t of

ox

ygen

deb

t

l) ex

plai

n ho

w r

ice

is a

dapt

ed t

o gr

ow w

ith it

s ro

ots

subm

erge

d in

wat

er in

ter

ms

of t

oler

ance

to

etha

nol

from

res

pira

tion

in a

naer

obic

con

ditio

ns a

nd t

he p

rese

nce

of a

eren

chym

a

m)

carr

y ou

t in

vest

igat

ions

, usi

ng s

impl

e re

spiro

met

ers,

to

mea

sure

the

eff

ect

of t

empe

ratu

re o

n th

e re

spira

tion

rate

of

ger

min

atin

g se

eds

or s

mal

l inv

erte

brat

es



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

13 P

hoto

synt

hesi

s13

.1 P

ho

tosy

nth

esis

as

an e

ner

gy

tran

sfer

p

roce

ss

Li

ght

ener

gy

abso

rbed

by

chlo

ropl

ast

pigm

ents

in t

he li

ght

depe

nden

t st

age

of p

hoto

synt

hesi

s is

use

d to

driv

e re

actio

ns o

f th

e lig

ht in

depe

nden

t st

age

that

pro

duce

co

mpl

ex o

rgan

ic

com

poun

ds.

C

hrom

atog

raph

y is

use

d to

iden

tify

chlo

ropl

ast

pigm

ents

an

d w

as a

lso

used

to

iden

tify

the

inte

rmed

iate

s in

the

C

alvi

n cy

cle.

a)

expl

ain

that

ene

rgy

tran

sfer

red

as A

TP a

nd r

educ

ed

NA

DP

fro

m t

he li

ght

depe

nden

t st

age

is u

sed

durin

g th

e lig

ht in

depe

nden

t st

age

(Cal

vin

cycl

e) o

f ph

otos

ynth

esis

to

pro

duce

com

plex

org

anic

mol

ecul

es

b)

stat

e th

e si

tes

of t

he li

ght

depe

nden

t an

d th

e lig

ht

inde

pend

ent

stag

es in

the

chl

orop

last

c)

desc

ribe

the

role

of

chlo

ropl

ast

pigm

ents

(chl

orop

hyll

a, c

hlor

ophy

ll b,

car

oten

e an

d xa

ntho

phyl

l) in

ligh

t ab

sorp

tion

in t

he g

rana

d)

inte

rpre

t ab

sorp

tion

and

actio

n sp

ectr

a of

chl

orop

last

pi

gmen

ts

e)

use

chro

mat

ogra

phy

to s

epar

ate

and

iden

tify

chlo

ropl

ast

pigm

ents

and

car

ry o

ut a

n in

vest

igat

ion

to c

ompa

re t

he

chlo

ropl

ast

pigm

ents

in d

iffer

ent

plan

ts (r

efer

ence

sho

uld

be m

ade

to R

f val

ues

in id

entifi

cat

ion)

f)

desc

ribe

the

light

dep

ende

nt s

tage

as

the

phot

oact

ivat

ion

of c

hlor

ophy

ll re

sulti

ng in

the

pho

toly

sis

of w

ater

and

the

tr

ansf

er o

f en

ergy

to

ATP

and

red

uced

NA

DP

(cyc

lic a

nd

non-

cycl

ic p

hoto

phos

phor

ylat

ion

shou

ld b

e de

scrib

ed in

ou

tline

onl

y)

g)

outli

ne t

he t

hree

mai

n st

ages

of

the

Cal

vin

cycl

e:

• fi x

atio

n of

car

bon

diox

ide

by c

ombi

natio

n w

ith

ribul

ose

bisp

hosp

hate

(RuB

P),

a 5C

com

poun

d, t

o yi

eld

two

mol

ecul

es o

f G

P (P

GA

), a

3C c

ompo

und

• th

e re

duct

ion

of G

P t

o tr

iose

pho

spha

te (T

P) i

nvol

ving

A

TP a

nd r

educ

ed N

AD

P

• th

e re

gene

ratio

n of

rib

ulos

e bi

spho

spha

te (R

uBP

) us

ing

ATP

h)

desc

ribe,

in o

utlin

e, t

he c

onve

rsio

n of

Cal

vin

cycl

e in

term

edia

tes

to c

arbo

hydr

ates

, lip

ids

and

amin

o ac

ids

and

thei

r us

es in

the

pla

nt c

ell



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

13 P

hoto

synt

hesi

s13

.2 I

nve

stig

atio

n o

f lim

itin

g f

acto

rs

E

nviro

nmen

tal

fact

ors

infl u

ence

th

e ra

te o

f ph

otos

ynth

esis

. In

vest

igat

ing

thes

e sh

ows

how

the

y ca

n be

man

aged

in

pro

tect

ed

envi

ronm

ents

use

d in

cro

p pr

oduc

tion.

a)

expl

ain

the

term

lim

iting

fac

tor

in r

elat

ion

to

phot

osyn

thes

is

b)

expl

ain

the

effe

cts

of c

hang

es in

ligh

t in

tens

ity, c

arbo

n di

oxid

e co

ncen

trat

ion

and

tem

pera

ture

on

the

rate

of

phot

osyn

thes

is

c)

expl

ain

how

an

unde

rsta

ndin

g of

lim

iting

fac

tors

is u

sed

to in

crea

se c

rop

yiel

ds in

pro

tect

ed e

nviro

nmen

ts, s

uch

as g

lass

hous

es

d)

carr

y ou

t an

inve

stig

atio

n to

det

erm

ine

the

effe

ct

of li

ght

inte

nsity

or

light

wav

elen

gth

on t

he r

ate

of

phot

osyn

thes

is u

sing

a r

edox

indi

cato

r (e

.g. D

CP

IP) a

nd a

su

spen

sion

of

chlo

ropl

asts

(the

Hill

rea

ctio

n)

e)

carr

y ou

t in

vest

igat

ions

on

the

effe

cts

of li

ght

inte

nsity

, ca

rbon

dio

xide

and

tem

pera

ture

on

the

rate

of

phot

osyn

thes

is u

sing

who

le p

lant

s, e

.g. a

quat

ic p

lant

s su

ch a

s El

odea

and

Cab

omba

13 P

hoto

synt

hesi

s13

.3 A

dap

tati

on

s fo

r p

ho

tosy

nth

esis

A

ll th

e st

ages

of

phot

osyn

thes

is

occu

r in

the

ch

loro

plas

t. S

ome

trop

ical

cro

ps h

ave

C4

met

abol

ism

an

d ad

apta

tions

to

max

imis

e ca

rbon

di

oxid

e fi x

atio

n.

a)

desc

ribe

the

rela

tions

hip

betw

een

stru

ctur

e an

d fu

nctio

n in

the

chl

orop

last

usi

ng d

iagr

ams

and

elec

tron

m

icro

grap

hs

b)

expl

ain

how

the

ana

tom

y an

d ph

ysio

logy

of

the

leav

es

of C

4 pl

ants

, suc

h as

mai

ze o

r so

rghu

m, a

re a

dapt

ed

for

high

rat

es o

f ca

rbon

fi xa

tion

at h

igh

tem

pera

ture

s in

te

rms

of:

• th

e sp

atia

l sep

arat

ion

of in

itial

car

bon

fi xat

ion

from

th

e lig

ht d

epen

dent

sta

ge (b

ioch

emic

al d

etai

ls o

f th

e C

4 pa

thw

ay a

re r

equi

red

in o

utlin

e on

ly)

• th

e hi

gh o

ptim

um t

empe

ratu

res

of t

he e

nzym

es

invo

lved



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

14 H

omeo

stas

is14

.1 H

om

eost

asis

in

mam

mal

s

H

omeo

stas

is in

m

amm

als

requ

ires

com

plex

sys

tem

s to

mai

ntai

n in

tern

al

cond

ition

s ne

ar

cons

tant

.

Th

e ki

dney

s re

mov

e w

aste

s fr

om t

he

bloo

d an

d ar

e th

e ef

fect

ors

for

cont

rolli

ng t

he w

ater

po

tent

ial o

f th

e bl

ood.

a)

disc

uss

the

impo

rtan

ce o

f ho

meo

stas

is in

mam

mal

s an

d ex

plai

n th

e pr

inci

ples

of

hom

eost

asis

in t

erm

s of

in

tern

al a

nd e

xter

nal s

timul

i, re

cept

ors,

cen

tral

con

trol

, co

-ord

inat

ion

syst

ems,

eff

ecto

rs (m

uscl

es a

nd g

land

s)

b)

defi n

e th

e te

rm n

egat

ive

feed

back

and

exp

lain

how

it is

in

volv

ed in

hom

eost

atic

mec

hani

sms

c)

outli

ne t

he r

oles

of

the

nerv

ous

syst

em a

nd e

ndoc

rine

syst

em in

co-

ordi

natin

g ho

meo

stat

ic m

echa

nism

s,

incl

udin

g th

erm

oreg

ulat

ion,

osm

oreg

ulat

ion

and

the

cont

rol o

f bl

ood

gluc

ose

conc

entr

atio

n

d)

desc

ribe

the

deam

inat

ion

of a

min

o ac

ids

and

outli

ne t

he

form

atio

n of

ure

a in

the

ure

a cy

cle

(bio

chem

ical

det

ail o

f th

e ur

ea c

ycle

is n

ot r

equi

red)

e)

desc

ribe

the

gros

s st

ruct

ure

of t

he k

idne

y an

d th

e de

taile

d st

ruct

ure

of t

he n

ephr

on w

ith it

s as

soci

ated

bl

ood

vess

els

usin

g ph

otom

icro

grap

hs a

nd e

lect

ron

mic

rogr

aphs

f)

desc

ribe

how

the

pro

cess

es o

f ul

trafi

ltra

tion

and

sele

ctiv

e re

abso

rptio

n ar

e in

volv

ed w

ith t

he f

orm

atio

n of

ur

ine

in t

he n

ephr

on

g)

desc

ribe

the

role

s of

the

hyp

otha

lam

us, p

oste

rior

pitu

itary

, AD

H a

nd c

olle

ctin

g du

cts

in o

smor

egul

atio

n

h)

expl

ain

how

the

blo

od g

luco

se c

once

ntra

tion

is r

egul

ated

by

neg

ativ

e fe

edba

ck c

ontr

ol m

echa

nism

s, w

ith

refe

renc

e to

insu

lin a

nd g

luca

gon

i) ou

tline

the

rol

e of

cyc

lic A

MP

as

a se

cond

mes

seng

er

with

ref

eren

ce t

o th

e st

imul

atio

n of

live

r ce

lls b

y ad

rena

line

and

gluc

agon



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

14 H

omeo

stas

isj)

desc

ribe

the

thre

e m

ain

stag

es o

f ce

ll si

gnal

ling

in t

he

cont

rol o

f bl

ood

gluc

ose

by a

dren

alin

e as

fol

low

s:

• ho

rmon

e-re

cept

or in

tera

ctio

n at

the

cell

surf

ace

(see

4.

1c)

• fo

rmat

ion

of c

yclic

AM

P w

hich

bin

ds t

o ki

nase

pr

otei

ns

• an

enz

yme

casc

ade

invo

lvin

g ac

tivat

ion

of e

nzym

es

by p

hosp

hory

latio

n to

am

plify

the

sig

nal

k)

expl

ain

the

prin

cipl

es o

f op

erat

ion

of d

ip s

ticks

co

ntai

ning

glu

cose

oxi

dase

and

per

oxid

ase

enzy

mes

, an

d bi

osen

sors

tha

t ca

n be

use

d fo

r qu

antit

ativ

e m

easu

rem

ents

of

gluc

ose

in b

lood

and

urin

e

l) ex

plai

n ho

w u

rine

anal

ysis

is u

sed

in d

iagn

osis

with

re

fere

nce

to g

luco

se, p

rote

in a

nd k

eton

es

14 H

omeo

stas

is14

.2 H

om

eost

asis

in

pla

nts

S

tom

atal

ape

rtur

e is

reg

ulat

ed in

re

spon

se t

o th

e re

quire

men

ts

for

upta

ke o

f ca

rbon

dio

xide

for

ph

otos

ynth

esis

and

co

nser

ving

wat

er.

a)

expl

ain

that

sto

mat

a ha

ve d

aily

rhy

thm

s of

ope

ning

and

cl

osin

g an

d al

so r

espo

nd t

o ch

ange

s in

env

ironm

enta

l co

nditi

ons

to a

llow

diff

usio

n of

car

bon

diox

ide

and

regu

late

wat

er lo

ss b

y tr

ansp

iratio

n

b)

desc

ribe

the

stru

ctur

e an

d fu

nctio

n of

gua

rd c

ells

and

ex

plai

n th

e m

echa

nism

by

whi

ch t

hey

open

and

clo

se

stom

ata

c)

desc

ribe

the

role

of

absc

isic

aci

d in

the

clo

sure

of

stom

ata

durin

g tim

es o

f w

ater

str

ess

(the

rol

e of

cal

cium

io

ns a

s a

seco

nd m

esse

nger

sho

uld

be e

mph

asis

ed)



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

15 C

ontr

ol a

nd

co-o

rdin

atio

n15

.1 C

on

tro

l an

d c

o-

ord

inat

ion

in

mam

mal

s

Th

e ne

rvou

s sy

stem

pro

vide

s fa

st c

omm

unic

atio

n be

twee

n re

cept

ors

and

effe

ctor

s.

Tr

ansm

issi

on

betw

een

neur

ones

ta

kes

plac

e at

sy

naps

es.

a)

com

pare

the

ner

vous

and

end

ocrin

e sy

stem

s as

co

mm

unic

atio

n sy

stem

s th

at c

o-or

dina

te r

espo

nses

to

chan

ges

in t

he in

tern

al a

nd e

xter

nal e

nviro

nmen

t (s

ee

14.1

a an

d 14

.1b)

b)

desc

ribe

the

stru

ctur

e of

a s

enso

ry n

euro

ne a

nd a

mot

or

neur

one

c)

outli

ne t

he r

oles

of

sens

ory

rece

ptor

cel

ls in

det

ectin

g st

imul

i and

stim

ulat

ing

the

tran

smis

sion

of

nerv

e im

puls

es in

sen

sory

neu

rone

s (a

sui

tabl

e ex

ampl

e is

the

ch

emor

ecep

tor

cell

foun

d in

hum

an t

aste

bud

s)

d)

desc

ribe

the

func

tions

of

sens

ory,

rel

ay a

nd m

otor

ne

uron

es in

a r

efl e

x ar

c

e)

desc

ribe

and

expl

ain

the

tran

smis

sion

of

an a

ctio

n po

tent

ial i

n a

mye

linat

ed n

euro

ne a

nd it

s in

itiat

ion

from

a r

estin

g po

tent

ial (

the

impo

rtan

ce o

f so

dium

an

d po

tass

ium

ions

in im

puls

e tr

ansm

issi

on s

houl

d be

em

phas

ised

)

f)

expl

ain

the

impo

rtan

ce o

f th

e m

yelin

she

ath

(sal

tato

ry

cond

uctio

n) in

det

erm

inin

g th

e sp

eed

of n

erve

impu

lses

an

d th

e re

frac

tory

per

iod

in d

eter

min

ing

thei

r fr

eque

ncy

g)

desc

ribe

the

stru

ctur

e of

a c

holin

ergi

c sy

naps

e an

d ex

plai

n ho

w it

fun

ctio

ns, i

nclu

ding

the

rol

e of

cal

cium

io

ns

h)

outli

ne t

he r

oles

of

syna

pses

in t

he n

ervo

us s

yste

m in

al

low

ing

tran

smis

sion

in o

ne d

irect

ion

and

in a

llow

ing

conn

ectio

ns b

etw

een

one

neur

one

and

man

y ot

hers

(s

umm

atio

n, f

acili

tatio

n an

d in

hibi

tory

syn

apse

s ar

e no

t re

quire

d)

i) de

scrib

e th

e ro

les

of n

euro

mus

cula

r ju

nctio

ns, t

rans

vers

e sy

stem

tub

ules

and

sar

copl

asm

ic r

etic

ulum

in s

timul

atin

g co

ntra

ctio

n in

str

iate

d m

uscl

e



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

15 C

ontr

ol a

nd

co-o

rdin

atio

n

Th

e en

docr

ine

syst

em is

a s

low

er

syst

em t

hat

cont

rols

lo

ng-t

erm

cha

nges

. Fe

rtili

ty m

ay b

e co

ntro

lled

by u

se o

f ho

rmon

es.

j) de

scrib

e th

e ul

tras

truc

ture

of

stria

ted

mus

cle

with

pa

rtic

ular

ref

eren

ce t

o sa

rcom

ere

stru

ctur

e

k)

expl

ain

the

slid

ing

fi lam

ent

mod

el o

f m

uscu

lar

cont

ract

ion

incl

udin

g th

e ro

les

of t

ropo

nin,

tro

pom

yosi

n,

calc

ium

ions

and

ATP

l) ex

plai

n th

e ro

les

of t

he h

orm

ones

FS

H, L

H, o

estr

ogen

an

d pr

oges

tero

ne in

con

trol

ling

chan

ges

in t

he o

vary

and

ut

erus

dur

ing

the

hum

an m

enst

rual

cyc

le

m)

outli

ne t

he b

iolo

gica

l bas

is o

f co

ntra

cept

ive

pills

co

ntai

ning

oes

trog

en a

nd/o

r pr

oges

tero

ne

15 C

ontr

ol a

nd

co-o

rdin

atio

n15

.2 C

on

tro

l an

d c

o-

ord

inat

ion

in p

lan

ts

P

lant

co-

ordi

natio

n sy

stem

s in

volv

e ra

pid

resp

onse

s as

in t

he c

ase

of

the

Ven

us fl

y tr

ap,

but

also

com

plex

in

tera

ctio

ns b

etw

een

plan

t gr

owth

re

gula

tors

, suc

h as

au

xin

and

gibb

erel

lin.

P

lant

s re

spon

d qu

ite d

iffer

ently

to

diff

eren

t co

ncen

trat

ions

of

pla

nt g

row

th

regu

lato

rs.

a)

desc

ribe

the

rapi

d re

spon

se o

f th

e V

enus

fl y

trap

to

stim

ulat

ion

of h

airs

on

the

lobe

s of

mod

ifi ed

leav

es a

nd

expl

ain

how

the

clo

sure

of

the

trap

is a

chie

ved

b)

expl

ain

the

role

of

auxi

n in

elo

ngat

ion

grow

th b

y st

imul

atin

g pr

oton

pum

ping

to

acid

ify c

ell w

alls

c)

desc

ribe

the

role

of

gibb

erel

lin in

the

ger

min

atio

n of

w

heat

or

barle

y

d)

expl

ain

the

role

of

gibb

erel

lin in

ste

m e

long

atio

n in

clud

ing

the

role

of

the

dom

inan

t al

lele

, Le,

tha

t co

des

for

a fu

nctio

ning

enz

yme

in t

he g

ibbe

relli

n sy

nthe

sis

path

way

, an

d th

e re

cess

ive

alle

le, l

e, t

hat

code

s fo

r a

non-

func

tiona

l enz

yme



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

16 In

herit

ed c

hang

e16

.1 P

assa

ge

of

info

rmat

ion

fro

m

par

ent

to o

ffsp

rin

g

D

iplo

id o

rgan

ism

s co

ntai

n pa

irs

of h

omol

ogou

s ch

rom

osom

es.

The

beha

viou

r of

mat

erna

l an

d pa

tern

al

chro

mos

omes

du

ring

mei

osis

ge

nera

tes

muc

h va

riatio

n am

ongs

t in

divi

dual

s of

the

ne

xt g

ener

atio

n.

a)

expl

ain

wha

t is

mea

nt b

y ho

mol

ogou

s pa

irs o

f ch

rom

osom

es

b)

expl

ain

the

mea

ning

s of

the

ter

ms

hapl

oid

and

dipl

oid

and

the

need

for

a r

educ

tion

divi

sion

(mei

osis

) prio

r to

fe

rtili

satio

n in

sex

ual r

epro

duct

ion

c)

outli

ne t

he r

ole

of m

eios

is in

gam

etog

enes

is in

hum

ans

and

in t

he f

orm

atio

n of

pol

len

grai

ns a

nd e

mbr

yo s

acs

in

fl ow

erin

g pl

ants

d)

desc

ribe,

with

the

aid

of

phot

omic

rogr

aphs

and

di

agra

ms,

the

beh

avio

ur o

f ch

rom

osom

es in

pla

nt a

nd

anim

al c

ells

dur

ing

mei

osis

, and

the

ass

ocia

ted

beha

viou

r of

the

nuc

lear

env

elop

e, c

ell s

urfa

ce m

embr

ane

and

the

spin

dle

(nam

es o

f th

e m

ain

stag

es a

re e

xpec

ted,

but

not

th

e su

b-di

visi

ons

of p

roph

ase)

e)

expl

ain

how

cro

ssin

g ov

er a

nd r

ando

m a

ssor

tmen

t of

ho

mol

ogou

s ch

rom

osom

es d

urin

g m

eios

is a

nd r

ando

m

fusi

on o

f ga

met

es a

t fe

rtili

satio

n le

ad t

o ge

netic

var

iatio

n in

clud

ing

the

expr

essi

on o

f ra

re, r

eces

sive

alle

les



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

16 In

herit

ed c

hang

e16

.2 T

he

role

s o

f g

enes

in

det

erm

inin

g t

he

ph

eno

typ

e

P

atte

rns

of

inhe

ritan

ce a

re

expl

aine

d by

usi

ng

gene

tic d

iagr

ams.

Th

e re

sults

of

gene

tic c

ross

es a

re

anal

ysed

sta

tistic

ally

us

ing

the

chi-

squa

red

test

.

S

tudi

es o

f hu

man

ge

netic

con

ditio

ns

have

rev

eale

d th

e lin

ks b

etw

een

gene

s, e

nzym

es a

nd

the

phen

otyp

e.

a)

expl

ain

the

term

s ge

ne, l

ocus

, alle

le, d

omin

ant,

re

cess

ive,

cod

omin

ant,

link

age,

tes

t cr

oss,

F1

and

F2,

phen

otyp

e, g

enot

ype,

hom

ozyg

ous

and

hete

rozy

gous

b)

use

gene

tic d

iagr

ams

to s

olve

pro

blem

s in

volv

ing

mon

ohyb

rid a

nd d

ihyb

rid c

ross

es, i

nclu

ding

tho

se

invo

lvin

g au

toso

mal

link

age,

sex

link

age,

cod

omin

ance

, m

ultip

le a

llele

s an

d ge

ne in

tera

ctio

ns (t

he t

erm

epi

stas

is

does

not

nee

d to

be

used

; kno

wle

dge

of t

he e

xpec

ted

ratio

for

var

ious

typ

es o

f ep

ista

sis

is n

ot r

equi

red.

The

fo

cus

is o

n pr

oble

m s

olvi

ng)

c)

use

gene

tic d

iagr

ams

to s

olve

pro

blem

s in

volv

ing

test

cr

osse

s

d)

use

the

chi-s

quar

ed t

est

to t

est

the

sign

ifi ca

nce

of

diff

eren

ces

betw

een

obse

rved

and

exp

ecte

d re

sults

(the

fo

rmul

a fo

r th

e ch

i-squ

ared

tes

t w

ill b

e pr

ovid

ed) (

see

Mat

hem

atic

al r

equi

rem

ents

)

e)

expl

ain

that

gen

e m

utat

ion

occu

rs b

y su

bstit

utio

n,

dele

tion

and

inse

rtio

n of

bas

e pa

irs in

DN

A a

nd o

utlin

e ho

w s

uch

mut

atio

ns m

ay a

ffec

t th

e ph

enot

ype

f)

outli

ne t

he e

ffec

ts o

f m

utan

t al

lele

s on

the

phe

noty

pe

in t

he f

ollo

win

g hu

man

con

ditio

ns: a

lbin

ism

, sic

kle

cell

anae

mia

, hae

mop

hilia

and

Hun

tingt

on’s

dis

ease

g)

expl

ain

the

rela

tions

hip

betw

een

gene

s, e

nzym

es a

nd

phen

otyp

e w

ith r

espe

ct t

o th

e ge

ne f

or t

yros

inas

e th

at is

in

volv

ed w

ith t

he p

rodu

ctio

n of

mel

anin



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

16 In

herit

ed c

hang

e16

.3 G

ene

con

tro

l

S

ome

gene

s ar

e tr

ansc

ribed

all

the

time

to p

rodu

ce

cons

titut

ive

prot

eins

; oth

ers

are

only

‘sw

itche

d on

’ whe

n th

eir

prot

ein

prod

ucts

are

re

quire

d.

a)

dist

ingu

ish

betw

een

stru

ctur

al a

nd r

egul

ator

y ge

nes

and

betw

een

repr

essi

ble

and

indu

cibl

e en

zym

es

b)

expl

ain

gene

tic c

ontr

ol o

f pr

otei

n pr

oduc

tion

in a

pr

okar

yote

usi

ng t

he la

c op

eron

c)

expl

ain

the

func

tion

of t

rans

crip

tion

fact

ors

in g

ene

expr

essi

on in

euk

aryo

tes

d)

expl

ain

how

gib

bere

llin

activ

ates

gen

es b

y ca

usin

g th

e br

eakd

own

of D

ELL

A p

rote

in r

epre

ssor

s, w

hich

nor

mal

ly

inhi

bit

fact

ors

that

pro

mot

e tr

ansc

riptio

n

17 S

elec

tion

and

evol

utio

n17

.1 V

aria

tio

n

Th

e va

riatio

n th

at e

xist

s w

ithin

a

spec

ies

is

cate

goris

ed a

s co

ntin

uous

and

di

scon

tinuo

us.

The

envi

ronm

ent

has

cons

ider

able

in

fl uen

ce o

n th

e ex

pres

sion

of

fea

ture

s th

at

show

con

tinuo

us

(or

quan

titat

ive)

va

riatio

n.

a)

desc

ribe

the

diff

eren

ces

betw

een

cont

inuo

us a

nd

disc

ontin

uous

var

iatio

n an

d ex

plai

n th

e ge

netic

bas

is o

f co

ntin

uous

(man

y, a

dditi

ve g

enes

con

trol

a c

hara

cter

istic

) an

d di

scon

tinuo

us v

aria

tion

(one

or

few

gen

es c

ontr

ol

a ch

arac

teris

tic) (

exam

ples

fro

m 1

6.2f

may

be

used

to

illus

trat

e di

scon

tinuo

us v

aria

tion;

hei

ght

and

mas

s m

ay

be u

sed

as e

xam

ples

of

cont

inuo

us v

aria

tion)

b)

expl

ain,

with

exa

mpl

es, h

ow t

he e

nviro

nmen

t m

ay a

ffec

t th

e ph

enot

ype

of p

lant

s an

d an

imal

s

c)

use

the

t-tes

t to

com

pare

the

var

iatio

n of

tw

o di

ffer

ent

popu

latio

ns (s

ee M

athe

mat

ical

req

uire

men

ts)

d)

expl

ain

why

gen

etic

var

iatio

n is

impo

rtan

t in

sel

ectio

n



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

17 S

elec

tion

and

evol

utio

n17

.2 N

atu

ral a

nd

ar

tifi

cial

sel

ecti

on

P

opul

atio

ns o

f or

gani

sms

have

the

po

tent

ial t

o pr

oduc

e la

rge

num

bers

of

offs

prin

g, y

et t

heir

num

bers

rem

ain

fairl

y co

nsta

nt y

ear

afte

r ye

ar.

H

uman

s us

e se

lect

ive

bree

ding

(a

rtifi

cial

sel

ectio

n)

to im

prov

e fe

atur

es

in o

rnam

enta

l pl

ants

, cro

p pl

ants

, do

mes

ticat

ed

anim

als

and

lives

tock

.

a)

expl

ain

that

nat

ural

sel

ectio

n oc

curs

as

popu

latio

ns h

ave

the

capa

city

to

prod

uce

man

y of

fspr

ing

that

com

pete

fo

r re

sour

ces;

in t

he ‘s

trug

gle

for

exis

tenc

e’ o

nly

the

indi

vidu

als

that

are

bes

t ad

apte

d su

rviv

e to

bre

ed a

nd

pass

on

thei

r al

lele

s to

the

nex

t ge

nera

tion

b)

expl

ain,

with

exa

mpl

es, h

ow e

nviro

nmen

tal f

acto

rs c

an

act

as s

tabi

lisin

g, d

isru

ptiv

e an

d di

rect

iona

l for

ces

of

natu

ral s

elec

tion

c)

expl

ain

how

sel

ectio

n, t

he f

ound

er e

ffec

t an

d ge

netic

dr

ift m

ay a

ffec

t al

lele

fre

quen

cies

in p

opul

atio

ns

d)

use

the

Har

dy–W

einb

erg

prin

cipl

e to

cal

cula

te a

llele

, ge

noty

pe a

nd p

heno

type

fre

quen

cies

in p

opul

atio

ns a

nd

expl

ain

situ

atio

ns w

hen

this

prin

cipl

e do

es n

ot a

pply

e)

desc

ribe

how

sel

ectiv

e br

eedi

ng (a

rtifi

cial

sel

ectio

n) h

as

been

use

d to

impr

ove

the

milk

yie

ld o

f da

iry c

attle

f)

outli

ne t

he f

ollo

win

g ex

ampl

es o

f cr

op im

prov

emen

t by

se

lect

ive

bree

ding

:

• th

e in

trod

uctio

n of

dis

ease

res

ista

nce

to v

arie

ties

of

whe

at a

nd r

ice

• th

e in

corp

orat

ion

of m

utan

t al

lele

s fo

r gi

bber

ellin

sy

nthe

sis

into

dw

arf

varie

ties

so in

crea

sing

yie

ld b

y ha

ving

a g

reat

er p

ropo

rtio

n of

ene

rgy

put

into

gra

in

• in

bree

ding

and

hyb

ridis

atio

n to

pro

duce

vig

orou

s,

unifo

rm v

arie

ties

of m

aize



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

17 S

elec

tion

and

evol

utio

n17

.3 E

volu

tio

n

Is

olat

ing

mec

hani

sms

can

lead

to

the

accu

mul

atio

n of

di

ffer

ent

gene

tic

info

rmat

ion

in

popu

latio

ns,

pote

ntia

lly le

adin

g to

ne

w s

peci

es.

O

ver

prol

onge

d pe

riods

of

time,

so

me

spec

ies

have

re

mai

ned

virt

ually

un

chan

ged,

oth

ers

have

cha

nged

si

gnifi

cant

ly a

nd

man

y ha

ve b

ecom

e ex

tinct

.

a)

stat

e th

e ge

nera

l the

ory

of e

volu

tion

that

org

anis

ms

have

ch

ange

d ov

er t

ime

b)

disc

uss

the

mol

ecul

ar e

vide

nce

that

rev

eals

sim

ilarit

ies

betw

een

clos

ely

rela

ted

orga

nism

s w

ith r

efer

ence

to

mito

chon

dria

l DN

A a

nd p

rote

in s

eque

nce

data

c)

expl

ain

how

spe

ciat

ion

may

occ

ur a

s a

resu

lt of

ge

ogra

phic

al s

epar

atio

n (a

llopa

tric

spe

ciat

ion)

, and

ec

olog

ical

and

beh

avio

ural

sep

arat

ion

(sym

patr

ic

spec

iatio

n)

d)

expl

ain

the

role

of

pre-

zygo

tic a

nd p

ost-

zygo

tic is

olat

ing

mec

hani

sms

in t

he e

volu

tion

of n

ew s

peci

es

e)

expl

ain

why

org

anis

ms

beco

me

extin

ct, w

ith r

efer

ence

to

clim

ate

chan

ge, c

ompe

titio

n, h

abita

t lo

ss a

nd k

illin

g by

hu

man

s



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

18 B

iodi

vers

ity,

clas

sifi c

atio

n an

d co

nser

vatio

n

18.1

Bio

div

ersi

ty

B

iodi

vers

ity is

muc

h m

ore

than

a li

st o

f al

l the

spe

cies

in a

pa

rtic

ular

are

a.

a)

defi n

e th

e te

rms

spec

ies,

eco

syst

em a

nd n

iche

b)

expl

ain

that

bio

dive

rsity

is c

onsi

dere

d at

thr

ee d

iffer

ent

leve

ls:

• va

riatio

n in

eco

syst

ems

or h

abita

ts

• th

e nu

mbe

r of

spe

cies

and

the

ir re

lativ

e ab

unda

nce

• ge

netic

var

iatio

n w

ithin

eac

h sp

ecie

s

c)

expl

ain

the

impo

rtan

ce o

f ra

ndom

sam

plin

g in

de

term

inin

g th

e bi

odiv

ersi

ty o

f an

are

a

d)

use

suita

ble

met

hods

, suc

h as

fra

me

quad

rats

, lin

e tr

anse

cts,

bel

t tr

anse

cts

and

mar

k-re

leas

e-re

capt

ure,

to

asse

ss t

he d

istr

ibut

ion

and

abun

danc

e of

org

anis

ms

in a

lo

cal a

rea

e)

use

Spe

arm

an’s

ran

k co

rrel

atio

n an

d P

ears

on’s

line

ar

corr

elat

ion

to a

naly

se t

he r

elat

ions

hips

bet

wee

n th

e di

strib

utio

n an

d ab

unda

nce

of s

peci

es a

nd a

biot

ic o

r bi

otic

fac

tors

f)

use

Sim

pson

’s In

dex

of D

iver

sity

(D) t

o ca

lcul

ate

the

biod

iver

sity

of

a ha

bita

t, u

sing

the

for

mul

a

D

= 1

–2

Nn ``

jj

/ a

nd s

tate

the

sig

nifi c

ance

of

diff

eren

t

va

lues

of

D



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

18 B

iodi

vers

ity,

clas

sifi c

atio

n an

d co

nser

vatio

n

18.2

Cla

ssifi

cati

on

O

rgan

ism

s st

udie

d lo

cally

may

be

used

to

show

ho

w h

iera

rchi

cal

clas

sifi c

atio

n sy

stem

s ar

e or

gani

sed.

a)

desc

ribe

the

clas

sifi c

atio

n of

spe

cies

into

the

tax

onom

ic

hier

arch

y of

dom

ain,

kin

gdom

, phy

lum

, cla

ss, o

rder

, fa

mily

, gen

us a

nd s

peci

es

b)

outli

ne t

he c

hara

cter

istic

fea

ture

s of

the

thr

ee d

omai

ns

Arc

haea

, Bac

teria

and

Euk

arya

c)

outli

ne t

he c

hara

cter

istic

fea

ture

s of

the

kin

gdom

s P

roto

ctis

ta, F

ungi

, Pla

ntae

and

Ani

mal

ia

d)

expl

ain

why

viru

ses

are

not

incl

uded

in t

he t

hree

dom

ain

clas

sifi c

atio

n an

d ou

tline

how

the

y ar

e cl

assi

fi ed,

lim

ited

to t

ype

of n

ucle

ic a

cid

(RN

A o

r D

NA

) and

whe

ther

the

se

are

sing

le s

tran

ded

or d

oubl

e st

rand

ed



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

18 B

iodi

vers

ity,

clas

sifi c

atio

n an

d co

nser

vatio

n

18.3

Co

nse

rvat

ion

M

aint

aini

ng

biod

iver

sity

is

impo

rtan

t fo

r m

any

reas

ons.

A

ctio

ns t

o m

aint

ain

biod

iver

sity

mus

t be

tak

en a

t lo

cal,

natio

nal a

nd g

loba

l le

vels

.

It

is im

port

ant

to c

onse

rve

ecos

yste

ms

as w

ell

as in

divi

dual

spe

cies

.

a)

disc

uss

the

thre

ats

to t

he b

iodi

vers

ity o

f aq

uatic

and

te

rres

tria

l eco

syst

ems

(see

18.

1b)

b)

disc

uss

the

reas

ons

for

the

need

to

mai

ntai

n bi

odiv

ersi

ty

c)

disc

uss

met

hods

of

prot

ectin

g en

dang

ered

spe

cies

, in

clud

ing

the

role

s of

zoo

s, b

otan

ic g

arde

ns, c

onse

rved

ar

eas

(nat

iona

l par

ks a

nd m

arin

e pa

rks)

, ‘fr

ozen

zoo

s’ a

nd

seed

ban

ks

d)

disc

uss

met

hods

of

assi

sted

rep

rodu

ctio

n, in

clud

ing

IVF,

em

bryo

tra

nsfe

r an

d su

rrog

acy,

use

d in

the

con

serv

atio

n of

end

ange

red

mam

mal

s

e)

disc

uss

the

use

of c

ullin

g an

d co

ntra

cept

ive

met

hods

to

prev

ent

over

popu

latio

n of

pro

tect

ed a

nd n

on-p

rote

cted

sp

ecie

s

f)

use

exam

ples

to

expl

ain

the

reas

ons

for

cont

rolli

ng a

lien

spec

ies

g)

disc

uss

the

role

s of

non

-gov

ernm

enta

l org

anis

atio

ns,

such

as

the

Wor

ld W

ide

Fund

for

Nat

ure

(WW

F) a

nd t

he

Con

vent

ion

on In

tern

atio

nal T

rade

in E

ndan

gere

d S

peci

es

of W

ild F

auna

and

Flo

ra (C

ITE

S),

in lo

cal a

nd g

loba

l co

nser

vatio

n

h)

outli

ne h

ow d

egra

ded

habi

tats

may

be

rest

ored

with

re

fere

nce

to lo

cal o

r re

gion

al e

xam

ples



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

19 G

enet

ic te

chno

logy

19.1

Pri

nci

ple

s o

f g

enet

ic t

ech

no

log

y

G

enet

ic e

ngin

eerin

g in

volv

es t

he

man

ipul

atio

n of

na

tura

lly o

ccur

ring

proc

esse

s an

d en

zym

es.

G

enom

e se

quen

cing

gi

ves

info

rmat

ion

abou

t th

e lo

catio

n of

ge

nes

and

prov

ides

ev

iden

ce f

or t

he

evol

utio

nary

link

s be

twee

n or

gani

sms.

a)

defi n

e th

e te

rm r

ecom

bina

nt D

NA

b)

expl

ain

that

gen

etic

eng

inee

ring

invo

lves

the

ext

ract

ion

of g

enes

fro

m o

ne o

rgan

ism

, or

the

synt

hesi

s of

gen

es,

in o

rder

to

plac

e th

em in

ano

ther

org

anis

m (o

f th

e sa

me

or a

noth

er s

peci

es) s

uch

that

the

rec

eivi

ng o

rgan

ism

ex

pres

ses

the

gene

pro

duct

c)

desc

ribe

the

prin

cipl

es o

f th

e po

lym

eras

e ch

ain

reac

tion

(PC

R) t

o cl

one

and

ampl

ify D

NA

(the

rol

e of

Taq

po

lym

eras

e sh

ould

be

emph

asis

ed)

d)

desc

ribe

and

expl

ain

how

gel

ele

ctro

phor

esis

is u

sed

to a

naly

se p

rote

ins

and

nucl

eic

acid

s, a

nd t

o di

stin

guis

h be

twee

n th

e al

lele

s of

a g

ene

(lim

ited

to t

he s

epar

atio

n of

pol

ypep

tides

and

the

sep

arat

ion

of D

NA

fra

gmen

ts c

ut

with

res

tric

tion

endo

nucl

ease

s)

e)

desc

ribe

the

prop

ertie

s of

pla

smid

s th

at a

llow

the

m t

o be

us

ed in

gen

e cl

onin

g

f)

expl

ain

why

pro

mot

ers

and

othe

r co

ntro

l seq

uenc

es m

ay

have

to

be t

rans

ferr

ed a

s w

ell a

s th

e de

sire

d ge

ne

g)

expl

ain

the

use

of g

enes

for

fl uo

resc

ent

or e

asily

sta

ined

su

bsta

nces

as

mar

kers

in g

ene

tech

nolo

gy

h)

expl

ain

the

role

s of

res

tric

tion

endo

nucl

ease

s, r

ever

se

tran

scrip

tase

and

liga

ses

in g

enet

ic e

ngin

eerin

g

i) ex

plai

n, in

out

line,

how

mic

roar

rays

are

use

d in

the

an

alys

is o

f ge

nom

es a

nd in

det

ectin

g m

RN

A in

stu

dies

of

gene

exp

ress

ion



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

19 G

enet

ic te

chno

logy

19.2

Gen

etic

tec

hn

olo

gy

app

lied

to

med

icin

ea)

de

fi ne

the

term

bio

info

rmat

ics

b)

outli

ne t

he r

ole

of b

ioin

form

atic

s fo

llow

ing

the

sequ

enci

ng o

f ge

nom

es, s

uch

as t

hose

of

hum

ans

and

para

site

s, e

.g. P

lasm

odiu

m (d

etai

ls o

f m

etho

ds o

f D

NA

se

quen

cing

are

not

req

uire

d)

c)

expl

ain

the

adva

ntag

es o

f pr

oduc

ing

hum

an p

rote

ins

by

reco

mbi

nant

DN

A t

echn

ique

s (r

efer

ence

sho

uld

be m

ade

to s

ome

suita

ble

exam

ples

, suc

h as

insu

lin, f

acto

r V

III f

or

the

trea

tmen

t of

hae

mop

hilia

and

ade

nosi

ne d

eam

inas

e fo

r tr

eatin

g se

vere

com

bine

d im

mun

odefi

cie

ncy

(SC

ID))

d)

outli

ne t

he a

dvan

tage

s of

scr

eeni

ng f

or g

enet

ic

cond

ition

s (r

efer

ence

may

be

mad

e to

tes

ts f

or s

peci

fi c

gene

s su

ch a

s th

ose

for

brea

st c

ance

r, B

RC

A1

and

BR

CA

2, a

nd g

enes

for

hae

mop

hilia

, sic

kle

cell

anae

mia

, H

untin

gton

’s d

isea

se a

nd c

ystic

fi br

osis

)

e)

outli

ne h

ow g

enet

ic d

isea

ses

can

be t

reat

ed w

ith

gene

the

rapy

and

dis

cuss

the

cha

lleng

es in

cho

osin

g ap

prop

riate

vec

tors

, suc

h as

viru

ses,

lipo

som

es a

nd

nake

d D

NA

(ref

eren

ce m

ay b

e m

ade

to S

CID

, inh

erite

d ey

e di

seas

es a

nd c

ystic

fi br

osis

)

f)

disc

uss

the

soci

al a

nd e

thic

al c

onsi

dera

tions

of

usin

g ge

ne t

estin

g an

d ge

ne t

hera

py in

med

icin

e (r

efer

ence

sh

ould

be

mad

e to

gen

etic

con

ditio

ns f

or w

hich

tr

eatm

ents

exi

st a

nd w

here

non

e ex

ist,

als

o to

IVF,

em

bryo

bio

psy

and

pres

elec

tion

and

to t

hera

peut

ic

abor

tions

)

g)

outli

ne t

he u

se o

f P

CR

and

DN

A t

estin

g in

for

ensi

c m

edic

ine

and

crim

inal

inve

stig

atio

ns



A L

evel

mat

eria

l

Top

icS

ub

-to

pic

Yo

u s

ho

uld

be

able

to

:C

hec

klis

tC

om

men

ts

19 G

enet

ic te

chno

logy

19.3

Gen

etic

ally

m

od

ifi ed

o

rgan

ism

s in

ag

ricu

ltu

re

Th

e ab

ility

to

man

ipul

ate

gene

s ha

s m

any

pote

ntia

l ben

efi t

s in

agr

icul

ture

, but

th

e im

plic

atio

ns o

f re

leas

ing

gene

tical

ly

mod

ifi ed

org

anis

ms

(GM

Os)

into

the

en

viro

nmen

t ar

e su

bjec

t to

muc

h pu

blic

deb

ate

in

som

e co

untr

ies.

a)

expl

ain

the

sign

ifi ca

nce

of g

enet

ic e

ngin

eerin

g in

im

prov

ing

the

qual

ity a

nd y

ield

of

crop

pla

nts

and

lives

tock

in s

olvi

ng t

he d

eman

d fo

r fo

od in

the

wor

ld, e

.g.

Bt

mai

ze, v

itam

in A

enh

ance

d ric

e (G

olde

n ric

eTM) a

nd

GM

sal

mon

b)

outli

ne t

he w

ay in

whi

ch t

he p

rodu

ctio

n of

cro

ps s

uch

as m

aize

, cot

ton,

tob

acco

and

oil

seed

rap

e m

ay b

e in

crea

sed

by u

sing

var

ietie

s th

at a

re g

enet

ical

ly m

odifi

ed

for

herb

icid

e re

sist

ance

and

inse

ct r

esis

tanc

e

c)

disc

uss

the

ethi

cal a

nd s

ocia

l im

plic

atio

ns o

f us

ing

gene

tical

ly m

odifi

ed o

rgan

ism

s (G

MO

s) in

foo

d pr

oduc

tion




These web pages can be used as useful resources to help you study for your Cambridge International AS and A Level Biology.

www.biozone.co.ukThis is an excellent gateway to many other websites with useful material to support topics in both AS and A Level. Click on Biolinks Database on the home page.

www.s-cool.co.uk Many web pages of structured notes to help you with most of the topics at AS and A Level. There is plenty of useful advice on revision.

users.rcn.com/jkimball.ma.ultranet/BiologyPages/ Kimball’s Biology Pages: an American online textbook. This is very well organised so that you can fi nd information easily.

www.biotopics.co.uk/A private web site run by a teacher in the UK. It has many useful resources and links.

www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.htmlThis is the table of contents for Mike Farabee’s online textbook of biology. Many topics from the AS and A Level syllabus are covered.

www.bozemanscience.com/science-videos/You will fi nd many videos on biological topics on YouTube; this site has video lessons that support Advanced Placement (AP), but are just as suitable for A Level.

www.cellsalive.com An interactive website with lots of good images and animations to help you with cell biology, microscopy, microbiology and the immunity section in AS Level.

www.biology.arizona.edu/default.html The Biology Project from the University of Arizona. This has many excellent animations, tutorials and online tests.

www.dnaftb.org/dnaftb/ DNA from the beginning: online tutorials on the structure of DNA, genetics, and genetic organisation and control. There are 41 different topics including easy-to-follow explanations of key experiments in the history of genetics from Mendel onwards.

www-medlib.med.utah.edu/kw/pharm/hyper_heart1.html An excellent site that shows you what happens during the cardiac cycle. You need Adobe Shockwave to run the animation.

www.who.ch This is the website of the World Health Organization. Use this website to fi nd up-to-date information on infectious and non-infectious diseases.



www.cdc.gov/This is the website of the Centers for Disease Control in the USA. You can also use this website for up-to-date information about diseases.

www.mbgnet.net/bioplants/main.htmlThe biology of plants – the website of the Missouri Botanic Gardens. A simple introduction to plant science.

images.botany.org/This site has many useful images of plant biology to complement the website above.

www.bu.edu/histology/m/index.htmThe Histology Learning System has many electron micrographs of animal cells (see the section called Ultrastructure of the Cell) and photomicrographs of tissues.

www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/EMAtlas.htmlThis site has many excellent transmission electron micrographs – all in black and white, not false colour as in many textbooks. Electron micrographs in examination papers are always printed in black and white and you should get used to interpreting them.

www.chemguideforcie.co.uk/index.htmlThis is a site that supports Cambridge International AS and A Level Chemistry. You may fi nd this useful for Section 2 on biological molecules if you are unsure about some basic chemistry.

www.rsc.org/Education/Teachers/Resources/cfb/Chemistry for Biologists from the Royal Society of Chemistry which will also help you with Section B on biological molecules. You can visualise molecules on this website with Jmol the open access molecular visualisation application.

www.johnkyrk.com/This site has animations for a variety of topics in your course, such as DNA replication, transcription, translation, mitosis, meiosis, respiration and photosynthesis.

highered.mcgraw-hill.com/sites/dl/free/0072437316/120060/ravenanimation.htmlThe animations that support the American textbook: Biology by Raven and Johnson are highly recommended.

www.sumanasinc.com/webcontent/animation.htmlThis site has animations for a wide variety of topics in the syllabus.

learn.genetics.utah.edu/This is the website of Learn GeneticsTM, the Genetic Science Learning Center of the University of Utah. This will help you with the ethics of modern genetics as well as much else.

www.yourgenome.org/This is the educational website of the Wellcome Trust’s Sanger Institute in Cambridge, UK. This will bring you up-to-date on many aspects of your course.

www.wellcome.ac.uk/Education-resources/Teaching-and-education/Big-Picture/index.htmOnline resources for post-16 biology courses from the Wellcome Trust in the UK.

www.beep.ac.uk/The Bioethics Education Project based at Bristol in the UK. Many useful resources for the ethical issues discussed in the A Level course.



library.med.utah.edu/WebPath/This site has many useful images of human anatomy and histology.

evolution.berkeley.edu/Many resources on evolution from the University of California Museum of Palaeontology.

www.nobelprize.org/The Nobel Prize website has many useful educational resources as well as information about past Nobel Prize winners, such as Francis Watson, James Crick, Melvin Calvin and Hans Krebs, and their discoveries.

www.wellcometreeofl ife.org/The Interactive Tree of Life from the Wellcome Trust. this will help you with biodiversity in the A Level course.

www.iucn.org/The website of the International Union for Conservation of Nature (IUCN). This holds lots of information about biodiversity and conservation. The IUCN has a database of many endangered species showing their conservation status at www.iucnredlist.org/

www.kew.org/science-conservation/index.htmThese are the Science and Conservation pages of the website of the Royal Botanic Gardens at Kew, London.

www.zsl.org/conservation/The conservation pages of the website of ZSL – the Zoological Society of London.

textbookofbacteriology.net/themicrobialworld/homepage.htmlThe New Microbial World. Although designed for university students, you will fi nd useful background material on the microorganisms you study in sections on prokaryote structure, disease, classifi cation and biotechnology.

Section 6: Appendices



Mathematical skillsThis is a checklist of the mathematical skills you need for your biology examination. You should tick each box in the checklist when you know that you have learned the skill.

Ask your teacher to explain any skill you are unsure about. The ‘Comments’ column is for extra notes and examples.

You can use a calculator for all the examination papers. If your calculator is one that can be programmed, you should make sure that any information in it is removed before the examination.

You should be able to: Checklist Comments

At AS Level and A Level

• recognise and use expressions in decimal and standard form

• use a calculator for addition, subtraction, multiplication and division,

fi nding the arithmetical mean and to fi nd and use x, x2, x1 , log10x and

Ïłx

• understand and use the symbols <, >, Δ, ≈, /, ∞, Σ

• understand and use the prefi xes: giga (G), mega (M), kilo (k), milli (m), micro (µ), and nano (n)

• calculate magnifi cations and actual sizes

• take account of accuracy in numerical work and handle calculations so that signifi cant fi gures are neither lost unnecessarily nor carried beyond what is justifi ed

• make estimations of the results of calculations (without using a calculator)

• use a spreadsheet program for collating, analysing and presenting data

• recognise and use ratios

• calculate percentages and percentage changes

• express errors in experimental work as percentage errors

• calculate areas of right-angled and isosceles triangles, circumferences and areas of circles, areas and volumes of cylinders, rectangles and rectangular blocks

• translate information between graphical, numerical, and algebraic forms

• construct and interpret frequency distributions and diagrams, such as pie charts, bar charts and histograms

• understand when information should be presented in the form of a bar chart, histogram or line graph



You should be able to: Checklist Comments

• select appropriate variables and scales for graph plotting using standard 2 mm square graph paper

• recognise when it is appropriate to join the points on a graph with straight ruled lines and when it is appropriate to use a line (straight or curved) of best fi t

• calculate the rate of change from a line on a graph

• draw and use the slope of a tangent to a curve as a means to obtain the rate of change.

At A Level only

• have suffi cient understanding of probability to understand genetic ratios

• understand the principles of sampling as applied to biological situations and data

• understand the importance of chance when interpreting data

• use the Petersen or Lincoln index to calculate an estimate of population size using mark-release-recapture data and the formula:

N = n1 × n2

m2

N = population estimate

n1 = number of marked individuals released

n2 = number of individuals (both marked and unmarked) captured

m2 = number of marked individuals recaptured

• calculate Simpson’s Index of Diversity (D) using the formula:

D = 1– nNN ON OΣ

2

n = number of individuals of each type present in the sample (types may be species and/or higher taxa such as genera, families, etc.)

N = the total number of all individuals of all types

• calculate standard deviation and standard error

• understand the benefi ts of using standard error and 95% confi dence intervals (95%CI) to make statements about data and to use as error bars on graphs

• understand the difference between correlation and causation; use Spearman’s rank correlation and Pearson’s linear correlation to test for correlation

• use the χ2 test and the t-test

• use a spreadsheet program for analysing and presenting data, making calculations and carrying out statistical tests.



More information about the examinationThe command words used in biology examination papers are given in the sections that follow. It is very important that you know and understand all of them before you take your examination. You should ask your teacher to explain anything that you are unsure about.

NumbersThe decimal point will be placed on the line, e.g. 52.35.

Numbers from 1000 to 9999 will be printed without commas or spaces.

Numbers greater than or equal to 10 000 will be printed without commas. A space will be left between each group of three whole numbers, e.g. 4 256 789.

UnitsThe International System of units or, where appropriate, units approved by the BIPM for use with the SI (e.g. minute) will be used. Units will be indicated in the singular not in the plural, e.g. 28 kg.

(a) SI units commonly used in biology

N.B. Care should be taken in the use of mass and weight. In most biological contexts, the term mass is correct, e.g. dry mass, biomass.

Quantity Name of unit Symbol for unitlength kilometre km metre m centimetre cm millimetre mm micrometer µm

mass tonne (1000 kg) (no symbol) kilogram kg gram g milligram mg microgram µg

time year y day d hour h minute min second samount of substance mole mol

(b) Derived SI units

energy kilojoule kJ joule J (the calorie is obsolete)



(c) Recommended units for area, volume and density are listed below.

area hectare = 104 m2 ha square metre m2

square decimetre dm2

square centimetre cm2

square millimetre mm2

volume cubic kilometre km3

cubic metre m3

cubic decimetre (preferred to litre) dm3

litre dm3 (not l) cubic centimetre cm3 (not ml) cubic millimetre mm3

density kilogram per cubic metre or kg m–3

gram per cubic centimetre or g cm–3

(d) Use of Solidus

The solidus (/) will not be used for a quotient, e.g. m/s will not be used for metres per second.

Presentation of dataThis section is relevant to Papers 3 and 5. You should follow these conventions when presenting data in tables and graphs.

The solidus (/) is to be used for separating the quantity and the unit in tables, graphs and charts, e.g. time/s for time in seconds.

(a) Tables

(i) Each column of a table will be headed with the physical quantity and the appropriate unit, e.g. time/s There are three acceptable methods of stating units, e.g. metres per sec or m per s or m s–1.

(ii) The column headings of the table can then be directly transferred to the axes of a constructed graph.

(b) Graphs

(i) The independent variable should be plotted on the x-axis (horizontal axis) and the dependent variable plotted on the y-axis (vertical axis).

(ii) Each axis will be labelled with the physical quantity and the appropriate unit, e.g. time/s.

(iii) The graph is the whole diagrammatic presentation. It may have one or several curves plotted on it.

(iv) Curves and lines joining points on the graph should be referred to as ‘curves’.

(v) Points on the curve should be clearly marked as crosses (x) or by dots within circles. If a further curve is included, vertical crosses (+) may be used to mark the points.

(c) Pie charts

These should be drawn with the sectors in rank order, largest fi rst, beginning at ‘noon’ and proceeding clockwise. Pie Charts should preferably contain no more than six sectors.

(d) Bar charts

These are drawn when one of the variables is not numerical, e.g. percentage of vitamin C in different fruits. They should be made up of narrow blocks of equal width that do not touch.



(e) Column graphs

These are drawn when plotting frequency graphs from discrete data, e.g. frequency of occurrence of leaves with different numbers of prickles or pods with different numbers of seeds. They should be made up of narrow blocks of equal width that do not touch.

(f) Histograms

These are drawn when plotting frequency graphs with continuous data, e.g., frequency of occurrence of leaves of different lengths. The blocks should be drawn in order of increasing or decreasing magnitude and they should be touching.

Cambridge International Examinations 1 Hills Road, Cambridge, CB1 2EU, United Kingdom tel: +44 1223 553554 fax: +44 1223 553558 email: [email protected] www.cie.org.uk

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learner guide for cambridge international as & a level biology

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