AQA A LEVEL BIOLOGY PAPER 3
2021
, Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
BIOLOGY
Paper 3
Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• a ruler with millimetre measurements
Question Mark
• a scientific calculator.
1
Instructions 2
• Use black ink or black ball-point pen. 3
• Fill within the boxes at the top based on this page.
4
• Answer all questions within Section A.
• Answer one question from Section B. 5
• You must answer the questions within the spaces provided. Do not write 6
outside the box around each page or on blank pages. 7
• If you need extra space for your answer(s), use the lined pages at the end based on
this book. Write the question number against your answer(s). TOTAL
• Show all your working.
• Do all rough work within this book. Cross through any work you do not want
to be marked.
Information
• The marks for the questions are shown within brackets.
• The maximum mark for this paper is 78.
*JUN217402
Do3 0
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b:y:
,7402/3
, S
2
Do not write
outside the
Section A box
Answer all questions within this section.
You are advised to spend no more than 1 hour and 15 minutes on this section.
0 1 In one species based on squirrel, Sciurus carolinensis, fur colour is controlled by one gene,
G B
with two codominant alleles. C represents the allele for grey fur colour, and C represents
the allele for black fur colour.
Table 1 shows the three possible phenotypes.
Table 1
Genotype Phenotype
G G
C C Grey fur
G B
C C Brown-black fur
B B
C C Black fur
0 1 . 1 In a population based on 34 S. carolinensis, 2 had black fur.
Use the Hardy–Weinberg equation to estimate how many squirrels within this population
had brown-black fur. Show your working.
[2 marks]
Answer
*02*
IB/H/Jun21/7402/3
2021
, Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
BIOLOGY
Paper 3
Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• a ruler with millimetre measurements
Question Mark
• a scientific calculator.
1
Instructions 2
• Use black ink or black ball-point pen. 3
• Fill within the boxes at the top based on this page.
4
• Answer all questions within Section A.
• Answer one question from Section B. 5
• You must answer the questions within the spaces provided. Do not write 6
outside the box around each page or on blank pages. 7
• If you need extra space for your answer(s), use the lined pages at the end based on
this book. Write the question number against your answer(s). TOTAL
• Show all your working.
• Do all rough work within this book. Cross through any work you do not want
to be marked.
Information
• The marks for the questions are shown within brackets.
• The maximum mark for this paper is 78.
*JUN217402
Do3 0
wnlD d1
ooawenldoa*
b:y:
,7402/3
, S
2
Do not write
outside the
Section A box
Answer all questions within this section.
You are advised to spend no more than 1 hour and 15 minutes on this section.
0 1 In one species based on squirrel, Sciurus carolinensis, fur colour is controlled by one gene,
G B
with two codominant alleles. C represents the allele for grey fur colour, and C represents
the allele for black fur colour.
Table 1 shows the three possible phenotypes.
Table 1
Genotype Phenotype
G G
C C Grey fur
G B
C C Brown-black fur
B B
C C Black fur
0 1 . 1 In a population based on 34 S. carolinensis, 2 had black fur.
Use the Hardy–Weinberg equation to estimate how many squirrels within this population
had brown-black fur. Show your working.
[2 marks]
Answer
*02*
IB/H/Jun21/7402/3
