1. Cell Ultrastructure

2. Transport Across The Membrane

3. Cell division

4. DNA & Protein Production

5. Enzymes

6. Genetic Engineering

7. Photosynthesis

8. Respiration

Topic 1

Cell Functions and Cell Functions and StructuresStructuresStructure Function Cell Type

Nucleus Controls cell activities All

Cytoplasm Site of chemical reactions All

Cell Membrane

Controls exchange of materials in/out of the cell

All

Ribosomes Site of protein synthesis All

Mitochondria Site of Aerobic Respiration (ATP/ Energy Production)

All

Chloroplasts Site of photosynthesis Green Plants

Vacuole Stores cell sap Plant, Fungal

Cell Wall Provides structure and prevents bursting

Plant, Fungal, Bacteria

Plasmid Extra ring of DNA Bacteria

TASK!Make Match Cards of the

structures and functions.

Fungal Cell

Bacterial Cell

3D Model HomeworkChoose 1 of the 4 cell types and

create a 3D model with structures clearly labelled.Model is due 1 week today.

Topic 2

Transport: Key Terms and Transport: Key Terms and DefinitionsDefinitionsTerm Definition

Passive Transport Movement of molecules without using ATP (energy)

Diffusion The movement of molecules from an area of high concentration to an area of low concentration down a concentration gradient

Osmosis The movement of water molecules from an area of high concentration to an area of low concentration down a concentration gradient

Active Transport The movement of molecules from an area of low concentration to an area of high concentration against a concentration gradient using ATP (energy)

Hypertonic A solution which has a lower water concentration to that of the cell contents

Isotonic A solution which has equal water concentration to that of the cells contents

Hypotonic A solution which has greater water concentration to that of the cell contents.

TASKMake Match Cards of these key terms and definitions.

Structure of the Cell Structure of the Cell MembraneMembrane•The cell membrane is made of PROTEINS and LIPID molecules in a BI-LAYER known as the fluid mosaic model.

•Proteins are spaced randomly and can be embedded or span the entire width of the membrane.

•These proteins can be CARRIERS during active transport or create protein CHANNELS/PORES for passive transport processes.

TASKUse the worksheet provided to create

your own model membrane.

Passive Transport: Passive Transport: DiffusionDiffusion•Diffusion is the passive transport of molecules from an area of high concentration to an area of low concentration down a concentration gradient.

•Diffusion does not require any energy as molecules which are small enough will pass through protein channels in/out of the cell as required.

•Examples of molecules which move by this transport method include: Oxygen, Carbon Dioxide and Glucose.

Experiment 1Using visking tubing

as a model membrane show that only small molecules

can pass through.

Passive Transport: Passive Transport: OsmosisOsmosis

•Osmosis is a special case of diffusion as it refers solely to the movement of WATER.

•Osmosis is the movement of water molecules from an area of high water concentration to an area of low water concentration down a concentration gradient.

•Osmosis occurs continually to maintain balance in organisms as too much or too little water can have a detrimental effect on the cell.

Osmotic Effects on CellsOsmotic Effects on CellsTHINK! What do you think each of the terms isotonic, hypotonic and hypertonic mean in this context? Use the diagrams to help you and discuss with your partner.

Experiment 2Using identical

cylinders of potato and various

concentrations of salt, identify the ISOTONIC water concentration in

plant tissue.

Active TransportActive Transport•Active transport involves the embedded protein molecules in the fluid membrane acting as carrier molecules to transport larger molecules across the membrane.

•Active transport requires energy (ATP) as molecules are moved AGAINST a concentration gradient from a high concentration to a low concentration.

•Examples of substances that enter a cell by active transport include ions such as Sodium and Potassium.

Topic 3

Cell Division: MitosisCell Division: Mitosis

•MITOSIS is the term given to the process of cell division.

•Cells must divide for GROWTH and REPAIR purposes in the body.

•There are 6 key stages in this process which ends in 2 daughter cells being IDENTICAL to the parent cell.

•They are genetically identical to prevent loss of information (sometimes written as maintaining the cells chromosome complement)

Stage

Description

1 Chromosomes become visible after undergoing DNA replication

2 Chromosomes shorten and pair up as chromatids

3 Nuclear membrane disappears and chromatids line up at the cells equator

4 Spindle fibres pull apart chromosomes to opposite poles in the cell

5 Nuclear membrane forms around groups of chromosomes and cytoplasm divides

6 2 identical daughter cells formed

TASKMake Picture and

Description match cards. Mitosis is a favourite exam question so you must know

EVERY stage.

TASKUse the resources provided to draw out the 6 stages of

Mitosis.

Cell CulturingCell Culturing•Cells can be grown in lab cultures for use in research or classroom practice.

•In order for any cell culture to be grown, the right growing conditions must be present; - Nutrient growth medium- Optimum pH- Optimum temperature

•Cell cultures can be grown on a variety of mediums including: - Agar plates- Agar slopes- Agar broths

Aseptic TechniquesAseptic Techniques•Aseptic techniques are used for all cell culturing experiment to AVOID CONTAMINATION.

•Aseptic techniques and conditions ensure sterile conditions as far as possible.

•Aseptic conditions include:- Hand washing- Hair tied back- Apron/Lab Coat- Working close to a flame- Disinfecting work area- Flaming bottle neck/ metal loop

Cell CulturingCell Culturing• When streaking an agar

plate to grow a cell culture you must follow the zig zag pattern as shown on the image.

• The initial streak will be very dense with your microbe so by streaking it out a further 3 times you can identify a single colony to transfer for growth.

THINK! What do you notice about the edge of each zig zag? Why do you think this is done?

Experiment 3Use your knowledge of aseptic techniques to culture yeast on an

agar plate.

Topic 4

Deoxyribonucleic Acid Deoxyribonucleic Acid (DNA)(DNA)•D.N.A is found inside the nucleus of a cell on threadlike structures called chromosomes.

•D.N.A. has a unique structure in that it consists of a 2 strands twisted together known as a double stranded helix. EXAM Favourite

DNA questions often come up as problem solving questions.

NucleotidesNucleotides•D.N.A is made up of repeating units called NUCLEOTIDES.•Nucleotides are made up of a phosphate, a ribose sugar and 1 of 4 bases.

•The 4 bases are; - Adenosine- Thymine- Cytosine- Guanine

•The bases are COMPLIMENTARY with A always pairing with T and G always pairing with C.

TASKUse the model kits in pairs

to create a model of the DNA helix and

complementary base pairs.

TASKUse the sweets provided to create an edible DNA helix. Ensure you have the bases in complimentary fashion

and can explain the structure. Take a smiling

selfie with your model before you eat it!

ProteinsProteins•The order of the bases on a DNA strand provide a specific code for a particular type of protein to be made at the ribosome.

•Examples of proteins and their functions are given in the table:

Protein Function

Enzyme Speeds up chemical reactions

Hormone Carries signals to target tissues from another area of the body to bring about an appropriate response.

Antibody Fights off infection/ foreign pathogens in the body

Making ProteinsMaking Proteins•Stage 1: Free nucleotides in the nucleus of the cell make a copy of the coding region on DNA. This single stranded molecule contains the blueprint instructions for making the protein and is called messenger RNA (mRNA).

•Stage 2: mRNA leaves the nucleus through pores and into the cytoplasm to a ribosome.

•Stage 3: The ribosome reads 3 bases (called a codon) at a time and brings the amino acid associated with that codon into position to form a polypeptide chain.

•Stage 4: This chain of amino acids is then folded into shape to form the new protein.

Topic 5

What Are Enzymes?What Are Enzymes?•Enzymes are BIOLOGICAL CATALYSTS found in all living organisms that:- speed up (or in some cases slow down) chemical reactions .- lower the activation energy required for the reaction to occur.- remain unchanged in the reaction.- are SPECIFIC.

•Enzymes are protein molecules which have a structure suited to fit only one substrate molecule. This area which fits the substrate is called the ACTIVE SITE and ensures SPECIFICITY is achieved (lock and key theory).

Enzyme Activity and Enzyme Activity and ExamplesExamples

Substrate Enzyme Product

Starch Amylase Maltose

Fats Lipase Fatty Acids and Glycerol

Hydrogen Peroxide

Catalase Water and Oxygen

• Enzyme activity is greatest in the enzymes OPTIMUM conditions such as the right temperature and pH.

• Anything below this will slow activity and anything above will stop activity entirely due to the active site becoming misshapen. This is when an enzyme DENATURES.

• There are two types of enzyme reactions: SYNTHESIS DEGRADATION

•

Experiment 4Investigating which

fruit has the greatest content of the

enzyme CATALASE.

Experiment 5Investigating

enzyme SPECIFICITY using

the enzyme AMYLASE.

Experiment 6Show that enzyme reactions can be

SYNTHESIS reactions using the enzyme PHOSPHORYLASE.

Experiment 7Investigate how

enzyme activity can be affected by

temperature and pH using the enzyme

AMYLASE.

Enzyme Activity GraphsEnzyme Activity Graphs

Enzymes AssignmentEnzymes Assignment•You will now be asked to write an assignment on the use of ENZYMES.

•You will be asked to write this in EXAM CONDITIONS IN CLASS.•It is essential that you:- Have a clear aim- Have a minimum word count of 500- Have two different sources (1 exp. & 1 other)- Process your sources into 2 different formats (tables to graphs)- Compare your sources- Can make a conclusion about your aim USING the info from your 2 sources.

•RAW data i.e. line graph from source 1, MUST have gridlines and have the FULL URL or reference for it.

Topic 6

Genetic Engineering Genetic Engineering •Genetic engineering is the process of ARTIFICIALLY altering the genome (Genetic make-up) of a cell.

•Scientists use genetic engineering to alter a bacterial plasmid to produce useful substances QUICKLY.

•2 substances which are produced in this manner are :- Human Growth Hormone (HGH)- Insulin

THINK! What do each of these substances treat? What other benefits are there of using Genetic Engineering to manufacture these substances?

EXAM Favourite Stages of Genetic Engineering are

always asked.Make sure you can identify each

stage AND describe what is happening. You might want to make your own match cards to help with

this.

Genetically Modifying Genetically Modifying OrganismsOrganisms

Has Science Has Science gone too far??gone too far??Research GM Research GM Crops on the Crops on the

iPads iPads

Topic 7

What is Photosynthesis?What is Photosynthesis?•Photosynthesis is the process which green plants undergo to create their own food using light energy.

•Water and Carbon Dioxide are the RAW materials.•Glucose and Oxygen are the PRODUCTS.•Photosynthesis happens in two stages: 1. Light Dependant Reaction (occurs in the grana of the chloroplasts)2. Carbon Fixation (occurs in the stroma of the chloroplasts)

LightWater + Carbon Dioxide Glucose + Oxygen Chlorophyll

Stage 1: Light Stage 1: Light DependantDependant•Water is absorbed into the plant by the roots.

•Light energy trapped in the grana is used to SPLIT water into Oxygen and Hydrogen.

•Oxygen is a WASTE product to plants and is released into the atmosphere through tiny pores called stomata.

•Hydrogen is required for Stage 2 and is moved by a carrier into the Stroma.

•ATP is also generated in this stage for use in Stage 2.

Stage 2: Carbon FixationStage 2: Carbon Fixation•Carbon Dioxide enters the plant from the atmosphere through the stomata.

•The ATP (energy) from stage 1 is used in a reaction to join the Carbon dioxide to the Hydrogen (again from stage 1) to form a sugar called GLUCOSE.

•Photosynthesis is an ENZYME CONTROLLED reaction and is therefore affected by temperatures out with an enzymes optimum.

Fates of GlucoseFates of Glucose•The glucose which is made during photosynthesis can be used by the plant in any 1 of the following 3 ways

•Firstly it can be used straight away as ENERGY

•Secondly it can be converted to CELLULOSE for the structural purpose of the cell wall.

•Finally it can be converted to the storage carbohydrate STARCH.

Limiting Factors of Limiting Factors of PhotosynthesisPhotosynthesis• There are 3 limiting factors associated with the RATE of photosynthesis.1. Carbon Dioxide Concentration2. Light Intensity3. Temperature

•Limiting factor questions always involve graphs as shown below:

• Anytime a point is on the initial INCLINE the limiting factor is always what is written on the horizontal axis.

• If a point is on the straight level-off line, then the factor limiting the photosynthesis is any of the other 2.

TASKPractice naming the limiting factors from the graphs drawn on

the board.

Experiment 7Test a leaf for starch in various conditions to prove that certain

factors can limit glucose production.

Topic 7

What is Respiration?What is Respiration?•Respiration is the process by which 1 molecule of glucose is broken down in the body to release ATP (energy)

Glucose + Oxygen Carbon Dioxide + Water (+ENERGY)

•There are 2 pathways for respiration:

1. AEROBIC (with Oxygen) 2. FERMENTATION (Without Oxygen)

THINK! Do you notice anything about the Respiration equation?

Linking Systems in Linking Systems in PlantsPlants

Understanding ATP Understanding ATP •ATP is a high energy compound made of 1 Adenosine and 3 inorganic phosphate molecules.

•The energy is stored in the third bond between the last 2 phosphates. When this bond is broken the energy is released forming the molecule ADP+Pi.

Aerobic RespirationAerobic Respiration•Aerobic Respiration occurs in two stages. The first stage is called GLYCOLOSIS and occurs in the CYTOPLASM.

•Glucose is SPLIT into 2 molecules of Pyruvic Acid.

•ATP (energy) has to be used to start this reaction, however the release of 4 ATP means that there is a NET GAIN of 2 ATP

•No Oxygen is required for this stage to occur, therefore common to both Aerobic and Fermentation pathways .

GLUCOSE

2x Pyruvic Acid

2 ATP

4 ATP

There is a NET GAIN of 2 ATP

Aerobic Respiration Aerobic Respiration Cont’dCont’d•The second stage of Aerobic respiration occurs in the MITOCHONDRIA and can only occur in the presence of oxygen.

•The 2 Pyruvate molecules undergo a series of chemical reactions to release CARBON DIOXIDE as waste.

•HYDROGEN is also released during this stage and is COMBINED with OXYGEN using the ATP to form water.

•Oxygen is described as the last Hydrogen ACCEPTOR in this chain of events.

Pyruvate

Carbon Dioxide

Hydrogen

Oxygen

Water

36 ATP Mad

e

FermentationFermentation• The second pathway in respiration is called

FERMENTATION and occurs in the absence of oxygen.

•In animals, when there is a lack of Oxygen for complete breakdown of glucose the pyruvate is converted into a substance called LACTIC ACID.

•Lactic Acid builds up in muscles causing fatigue.

•When oxygen is available once again, the lactic acid is converted back into pyruvate for the aerobic cycle to continue.

•We say that an OXYGEN DEBT has been paid.

FermentationFermentation•In plants/fungi etc, when there is a lack of oxygen for complete breakdown of glucose the pyruvate is converted into ethanol and carbon dioxide.

•This process is completely irreversible.

•We can use fermentation to our advantage in certain industries such as brewing and baking.

THINK! Why do you not taste alcohol in bakery products such as bread and cakes?

Experiment 8Investigate how carbon dioxide

produced in fermentation of yeast can be useful in the baking

industry.