AcePapers
A Level Biology B (Edexcel specification 9BI0)
Advanced Physiology, Evolution &
Ecology (Paper 2)
Practice question paper
Practice for 9BI0 Paper 2
Time allowed 1 hour 45 minutes
Total marks 90
Equipment Calculator, ruler, HB pencil
Before you start
• Write in black ink. A pencil may be used for graphs and drawings.
• Attempt every question and write each answer in the space below it; you may not need
all of the space.
• The number of marks for each part is given in brackets. Use it to judge how much to
write and how long to spend.
• Questions labelled with an asterisk (*) also reward a clear, logically sequenced answer in
which your points are connected.
• Show your working in calculations and give units where they are needed.
• Leave time at the end to read through your answers.
Written by AcePapers
Independent practice paper written for revision. Not an official Pearson paper
and not affiliated with or endorsed by Pearson.
AcePapers · 9BI0 Paper 2 · independent practice material Page 1
, Answer every question. Where a multiple-choice question has boxes, mark your chosen answer with a
cross. To change it, draw a line through the cross and mark the new box.
1 In a species of flowering plant, the allele for tall stem (T) is dominant to the allele for
short stem (t), and the allele for purple flowers (P) is dominant to the allele for white
flowers (p). The two genes are on different chromosomes.
(a) A plant with genotype TtPp was crossed with a plant with genotype ttpp.
Give the genotypes of all the gametes produced by the TtPp plant. (1)
Phenotype Observed (O) Expected (E) (O − E)2 ÷ E
tall, purple 68
tall, white 55
short, purple 52
short, white 65
(b) The table shows the offspring of this cross. Complete the table and calculate
the chi-squared value, using χ2 = Σ(O − E)2 ÷ E (3)
χ2 = ................................................
Degrees of freedom 1 2 3 4 5
Critical value at p = 0.05 3.84 5.99 7.82 9.49 11.07
(c) Use the table of critical values to explain what the result shows. (2)
(d) Suggest how the results would differ if the two genes were close together
on the same chromosome. (2)
[Question 1: 8 marks]
AcePapers · 9BI0 Paper 2 · independent practice material Page 2
, 2 Genetic variation in populations can change over time.
(a) A recessive genetic condition affects 1 in 2500 people in a population. Use
the Hardy–Weinberg equation to calculate the percentage of the population
who are heterozygous carriers. (3)
= ................................................ %
(b) Give two conditions needed for allele frequencies in a population to stay
constant. (2)
(c) Two populations of a lizard species became separated when rising sea
levels formed two islands. After many thousands of years the lizards on the
two islands could no longer interbreed. Explain how the two species formed. (4)
[Question 2: 9 marks]
3 The graph shows changes in the potential difference across the membrane of an axon
during an action potential.
AcePapers · 9BI0 Paper 2 · independent practice material Page 3
A Level Biology B (Edexcel specification 9BI0)
Advanced Physiology, Evolution &
Ecology (Paper 2)
Practice question paper
Practice for 9BI0 Paper 2
Time allowed 1 hour 45 minutes
Total marks 90
Equipment Calculator, ruler, HB pencil
Before you start
• Write in black ink. A pencil may be used for graphs and drawings.
• Attempt every question and write each answer in the space below it; you may not need
all of the space.
• The number of marks for each part is given in brackets. Use it to judge how much to
write and how long to spend.
• Questions labelled with an asterisk (*) also reward a clear, logically sequenced answer in
which your points are connected.
• Show your working in calculations and give units where they are needed.
• Leave time at the end to read through your answers.
Written by AcePapers
Independent practice paper written for revision. Not an official Pearson paper
and not affiliated with or endorsed by Pearson.
AcePapers · 9BI0 Paper 2 · independent practice material Page 1
, Answer every question. Where a multiple-choice question has boxes, mark your chosen answer with a
cross. To change it, draw a line through the cross and mark the new box.
1 In a species of flowering plant, the allele for tall stem (T) is dominant to the allele for
short stem (t), and the allele for purple flowers (P) is dominant to the allele for white
flowers (p). The two genes are on different chromosomes.
(a) A plant with genotype TtPp was crossed with a plant with genotype ttpp.
Give the genotypes of all the gametes produced by the TtPp plant. (1)
Phenotype Observed (O) Expected (E) (O − E)2 ÷ E
tall, purple 68
tall, white 55
short, purple 52
short, white 65
(b) The table shows the offspring of this cross. Complete the table and calculate
the chi-squared value, using χ2 = Σ(O − E)2 ÷ E (3)
χ2 = ................................................
Degrees of freedom 1 2 3 4 5
Critical value at p = 0.05 3.84 5.99 7.82 9.49 11.07
(c) Use the table of critical values to explain what the result shows. (2)
(d) Suggest how the results would differ if the two genes were close together
on the same chromosome. (2)
[Question 1: 8 marks]
AcePapers · 9BI0 Paper 2 · independent practice material Page 2
, 2 Genetic variation in populations can change over time.
(a) A recessive genetic condition affects 1 in 2500 people in a population. Use
the Hardy–Weinberg equation to calculate the percentage of the population
who are heterozygous carriers. (3)
= ................................................ %
(b) Give two conditions needed for allele frequencies in a population to stay
constant. (2)
(c) Two populations of a lizard species became separated when rising sea
levels formed two islands. After many thousands of years the lizards on the
two islands could no longer interbreed. Explain how the two species formed. (4)
[Question 2: 9 marks]
3 The graph shows changes in the potential difference across the membrane of an axon
during an action potential.
AcePapers · 9BI0 Paper 2 · independent practice material Page 3
