1
AQA A-Level Biology 7402/2 Paper
2 Actual Exam Questions and Mark
Scheme 2026/2027 | June Series Practice
Exam | Pass Guarantee
Q001: The graph below shows the change in frequency of a recessive allele in a
population of Drosophila over 50 generations.
After generation 30 the allele frequency stabilises at 0.05. Which explanation is
consistent with this stabilisation?
Options:
A. The recessive allele has become fixed in the population
B. The recessive allele is now advantageous in the homozygous state
C. Heterozygote advantage and mutation–selection balance are operating -
CORRECT
D. Genetic drift has eliminated the dominant allele
ANSWER: C
Q002: In a population of 10,000 mice the frequency of the recessive allele (a)
causing albinism is 0.3. Assuming Hardy–Weinberg equilibrium, how many
heterozygous individuals would be expected?
Options:
A. 900
B. 2100
C. 4200 - CORRECT
D. 4900
ANSWER: C
Q003: Which of the following best describes the role of inducers in the control of
gene expression in prokaryotes?
Options:
A. They bind to repressor proteins to activate them
B. They bind to operator DNA to block RNA polymerase
C. They bind to repressor proteins to release operator DNA - CORRECT
, 2
D. They bind to promoter DNA to increase transcription
ANSWER: C
Q004: A student performed the AQA required practical to investigate the effect of
auxin concentration on root growth. Which statistical test is most appropriate to
determine whether any observed differences are significant?
Options:
A. Chi-squared test
B. Student’s t-test - CORRECT
C. Simpson’s index
D. Spearman’s rank correlation
ANSWER: B
Q005: The diagram shows part of a gene that codes for a transmembrane protein. A
mutation changes the 7th base from C to A. Which type of mutation is this?
Options:
A. Silent mutation
B. Missense mutation - CORRECT
C. Nonsense mutation
D. Frameshift mutation
ANSWER: B
Q006: Which piece of evidence provides the strongest support for the theory of
evolution by natural selection?
Options:
A. Similarities in bone structure between the pentadactyl limb of mammals
B. Observed increase in beak depth of Galápagos finches after a drought -
CORRECT
C. Presence of homologous proteins in different species
D. Geographical distribution of marsupials
ANSWER: B
Q007: In a large population of snails shell colour is controlled by a single gene
with two alleles. Birds selectively eat the least-camouflaged individuals. Which
statement describes this selection pressure?
Options:
A. It increases allele frequency of the cryptic allele - CORRECT
AQA A-Level Biology 7402/2 Paper
2 Actual Exam Questions and Mark
Scheme 2026/2027 | June Series Practice
Exam | Pass Guarantee
Q001: The graph below shows the change in frequency of a recessive allele in a
population of Drosophila over 50 generations.
After generation 30 the allele frequency stabilises at 0.05. Which explanation is
consistent with this stabilisation?
Options:
A. The recessive allele has become fixed in the population
B. The recessive allele is now advantageous in the homozygous state
C. Heterozygote advantage and mutation–selection balance are operating -
CORRECT
D. Genetic drift has eliminated the dominant allele
ANSWER: C
Q002: In a population of 10,000 mice the frequency of the recessive allele (a)
causing albinism is 0.3. Assuming Hardy–Weinberg equilibrium, how many
heterozygous individuals would be expected?
Options:
A. 900
B. 2100
C. 4200 - CORRECT
D. 4900
ANSWER: C
Q003: Which of the following best describes the role of inducers in the control of
gene expression in prokaryotes?
Options:
A. They bind to repressor proteins to activate them
B. They bind to operator DNA to block RNA polymerase
C. They bind to repressor proteins to release operator DNA - CORRECT
, 2
D. They bind to promoter DNA to increase transcription
ANSWER: C
Q004: A student performed the AQA required practical to investigate the effect of
auxin concentration on root growth. Which statistical test is most appropriate to
determine whether any observed differences are significant?
Options:
A. Chi-squared test
B. Student’s t-test - CORRECT
C. Simpson’s index
D. Spearman’s rank correlation
ANSWER: B
Q005: The diagram shows part of a gene that codes for a transmembrane protein. A
mutation changes the 7th base from C to A. Which type of mutation is this?
Options:
A. Silent mutation
B. Missense mutation - CORRECT
C. Nonsense mutation
D. Frameshift mutation
ANSWER: B
Q006: Which piece of evidence provides the strongest support for the theory of
evolution by natural selection?
Options:
A. Similarities in bone structure between the pentadactyl limb of mammals
B. Observed increase in beak depth of Galápagos finches after a drought -
CORRECT
C. Presence of homologous proteins in different species
D. Geographical distribution of marsupials
ANSWER: B
Q007: In a large population of snails shell colour is controlled by a single gene
with two alleles. Birds selectively eat the least-camouflaged individuals. Which
statement describes this selection pressure?
Options:
A. It increases allele frequency of the cryptic allele - CORRECT
