6134_01_que_20090612

Paper Reference(s)

6134/01Edexcel GCEBiology (Salters-Nuffield)AdvancedUnit Test 4Friday 12 June 2009 – AfternoonTime: 1 hour 15 minutes

Materials required for examination Items included with question papersRuler NilCalculator

Instructions to CandidatesIn the boxes above, write your centre number, candidate number, your surname, initial(s) and signature.Check that you have the correct question paper.Answer ALL questions. Write your answers in the spaces provided in this question paper.If you need to use additional answer sheets, attach them loosely but securely inside this booklet.Show all the steps in any calculations and state the units. Calculators may be used.Include diagrams in your answers where these are helpful.

Information for CandidatesThe marks for individual questions and parts of questions are shown in round brackets: e.g. (2).There are 6 questions in this question paper. The total mark for this paper is 60.There are 16 pages in this question paper. Any blank pages are indicated.

Advice to CandidatesYou will be assessed on your ability to organise and present information, ideas, descriptions and arguments clearly and logically, taking into account your use of grammar, punctuation and spelling.

Examiner’s use only

Team Leader’s use only

Question Leave Number Blank

1

2

3

4

5

6

Total

Surname Initial(s)

Signature

Centre No.

*N34141A0116*Turn over

Candidate No.

Paper Reference

6 1 3 4 0 1

This publication may be reproduced only in accordance with Edexcel Limited copyright policy. ©2009 Edexcel Limited.

Printer’s Log. No.

N34141AW850/R6134/57570 4/4/

2

*N34141A0216*

BLANK PAGE

Leave blank

3

Turn over*N34141A0316*

Answer ALL questions in the spaces provided

1. Explain what is meant by each of the following terms.

(a) Speciation

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(b) Phagocytosis

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(c) Abiotic factor

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2) Q1

(Total 6 marks)

Leave blank

4

*N34141A0416*

2. Harlequin ladybirds were not found in the UK before 2004. Since their arrival from mainland Europe they have become established and their distribution now includes most of the south of England. Their position in a food web is shown in the diagram below.

(a) It is possible that harlequin ladybirds are causing native species to become less abundant. Use the information in the diagram to suggest explanations for this.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(b) Explain how harlequin ladybirds might reduce biodiversity.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(3)

Producers

Aphids

Native ladybird species

Butterflylarvae

Harlequin ladybirds

Moth larvae

Leave blank

5


(c) An investigation was carried out to determine the energy flow through three of the trophic levels in a 1000 m2 area of a habitat. The energy flow through these trophic levels, in one year, was estimated. The results are shown in the table below.

Trophic level Energy / kJ m–2 yr–1

Producers 2196

Primary consumers 864

Secondary consumers 42

(i) Explain what is meant by a trophic level.

................................................................................................................................

................................................................................................................................(1)

(ii) Calculate the energy that is lost between producers and secondary consumers in this 1000 m2 area in a year. Show your working.

Answer ........................................(3)

(iii) Explain why some of the energy available to producers is not available to primary consumers.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................(3) Q2

(Total 12 marks)

Leave blank

6

*N34141A0616*

3. After a person dies, the skeletal muscles will undergo contraction. In an investigation, the degree of contraction of muscle fibres kept at 37 °C and at 25 °C was measured. The degree of contraction was recorded as a percentage of the maximum contraction of the muscle fibre.

The results are shown in the graph below.

(a) Describe the effect of temperature on the degree of contraction of muscle fibres.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(3)

��

��

��

��

��

��

��

��

��

��

��

��

��

� � � � � � � � �

� � �

�� !��

� � � �

Leave blank

7


(b) The degree of contraction in muscles can be used to estimate the time of death of a body. Using the information in the graph, explain why it is important to know the temperature of the environment the dead body is in.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(c) Give two other ways in which time of death can be estimated.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2) Q3

(Total 7 marks)

8

*N34141A0816*

BLANK PAGE

Leave blank

9


4. The aluminium ions in acid soils are usually toxic to plant roots, inhibiting their growth. Some maize plants grow well on acid soils containing a high concentration of aluminium ions. These maize plants have a tolerance to aluminium ions.

(a) Suggest how tolerance to high concentrations of aluminium ions could be of benefit to these maize plants.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(b) The distribution of maize plants in a field might be affected by soil pH. Describe, giving practical details, how the distribution of plants could be estimated and related to a soil factor such as pH.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(4)

Leave blank

10

*N34141A01016*

(c) The tolerance of maize plants to aluminium ions depends on two genes, alt1 and alt2. A study was carried out to investigate the effect of high concentrations of aluminium ions on root growth in maize plants of known genotypes.

(i) Plants known to be heterozygous for both of the genes were crossed and the seeds collected.

Draw a genetic diagram to show the genotypes expected in the seeds produced by this cross. Use the symbols A and a to represent the alleles for alt1 and the symbols B and b to represent the alleles for alt2.

(3)

(ii) All the seeds produced from this genetic cross were grown in the presence of a high concentration of aluminium ions. The growth of the roots in the plants was observed and recorded. The results are shown in the table below along with a possible genetic explanation.

Growth seen in the roots Number of plants Possible genetic

explanation

Normal 184 At least one dominant allele for both genes is present

Reduced 62 At least one dominant allele for alt1 is present

None 78 No dominant allele for alt1 is present

Leave blank

11


Using all the information in the table, give the genotypes for the plants that show a phenotype of reduced root growth.

................................................................................................................................

................................................................................................................................(1)

(iii) Suggest an explanation for the ratio of the three phenotypes shown in the table.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................(2) Q4

(Total 12 marks)

Leave blank

12

*N34141A01216*

5. T helper cells are an important part of the immune system. HIV causes the destruction of T helper cells and can cause the development of AIDS.

(a) Describe two effects of a lack of T helper cells.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(2)

(b) (i) Explain how the immune system brings about the destruction of a virus in the bloodstream.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................(3)

(ii) Explain how the immune system of a previously infected person would respond to a subsequent infection by the same virus.

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................

................................................................................................................................(3)

Leave blank

13


(c) It has been discovered that some people are resistant to HIV infection because they have a genetic difference that allows their immune system to destroy the virus very effectively.

A new strain of HIV has been found in people who are resistant to HIV. This strain is very similar to previous strains, but has genetic differences that prevent it from being destroyed by their immune systems. However, the virus is unable to replicate properly which means that only small numbers are present in the bloodstream and AIDS does not develop.

Suggest how this is an example of an ‘evolutionary race’ between HIV and humans.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(4) Q5

(Total 12 marks)

Leave blank

14

*N34141A01416*

6. An investigation was carried out into the effects of light intensity on the growth of two species of plant, species A and species B. The total growth per day and the leaf area to mass ratio were measured. The results are shown in the graphs below.

��

��

��

��

��

��

��

��

��

��

�

� ��

��

��

�

�

�

�

�

�

�

�

�

�

��

� ��

� �� !

��

��

��

��

��

��

��

��

� �

� � � � � � � �

� ��

��

��

�

�

�

��

�

�

�

�

�

!��

� "�� #

� "�� $

Leave blank

15


(a) Suggest which of these plants is likely to be more successful in the conditions of low light intensity on a woodland floor. Use information from the graphs to explain your answer.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(3)

(b) Both of these species of plants have a low rate of growth at low light intensities. Use your knowledge of photosynthesis to suggest an explanation for this.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(5)

QUESTION 6 CONTINUES ON THE NEXT PAGE

Leave blank

16

*N34141A01616*

(c) Explain how a lower rate of respiration can affect plant productivity.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................(3)

TOTAL FOR PAPER: 60 MARKS

END

Q6

(Total 11 marks)

6134_01_que_20090612

Documents