plumiGenotype, environment and phenotype: Edexcel International A Level Biology questions
Every Edexcel International A Level Biology exam question on Genotype, environment and phenotype (specification points 3.20–3.21), 2019–2025, with its mark scheme and examiner’s report.
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Q8(a)(i)
The whole paper ↗Q8(a)(ii)
The whole paper ↗Q8(b)
The whole paper ↗Q8(f)
The whole paper ↗Q8(h)
The whole paper ↗Q5(d)(ii)
The whole paper ↗Your answerQ7(c)(i)
The whole paper ↗Q7(c)(ii)
The whole paper ↗Q9(b)
The whole paper ↗Q6(d)(i)
The whole paper ↗Q6(d)(ii)
The whole paper ↗Q5(a)(ii)
The whole paper ↗Q5(c)
The whole paper ↗Q8(b)(i)
The whole paper ↗Your answerQ8(b)(ii)
The whole paper ↗Q3(c)(i)
The whole paper ↗Q3(c)(ii)
The whole paper ↗Q5(b)(i)
The whole paper ↗Your answerQ5(b)(ii)
The whole paper ↗Your answerQ5(c)(i)
The whole paper ↗
All 41 questions on Genotype, environment and phenotype, as a list
- June 2025, Unit 4, Q8(a)(i) (1 mark): The pivotal temperature (Tpiv) is the temperature at which equal numbers of males and females are produced. Label the Tpiv for turtles on the graph. (1)
- June 2025, Unit 4, Q8(a)(ii) (3 marks): Describe the effect of the temperature of the sand on the percentage of males produced in these three reptiles. (3)
- June 2025, Unit 4, Q8(b) (4 marks): The embryos in newly-laid eggs have immature reproductive organs that can develop into either male reproductive organs or female reproductive organs. In turtles
- June 2025, Unit 5, Q8(f) (2 marks): Explain how environmental factors such as temperature could determine the sex of an animal (paragraph 14). (2)
- June 2025, Unit 5, Q8(h) (2 marks): Explain how epigenetic changes could ensure that the ‘gene output’ from the X chromosomes in females is the same as in males (paragraph 19). (2)
- January 2025, AS Unit 2, Q5(d)(ii) (1 mark): The width of peony leaves is an example of polygenic inheritance. Which row is correct for the width of peony leaves? (1) Leaf width is One gene determines dete
- January 2025, AS Unit 2, Q7(c)(i) (2 marks): Suggest the role of the enzyme DNA methyltransferase (DNMT) in the process of DNA methylation. (2)
- January 2025, AS Unit 2, Q7(c)(ii) (6 marks): Some cancers can be caused by the methylation of a tumour suppressor gene called RASSF1. Tumour suppressor genes can slow down cell division or cause cell death
- January 2025, Unit 4, Q9(b) (3 marks): One group of ERVs code for viral envelope proteins. In normal cells, these proteins are not synthesised due to epigenetic regulation. Explain how epigenetic reg
- October 2024, AS Unit 2, Q6(d)(i) (2 marks): Explain how DNA methylation can alter the expression of some genes. (2)
- October 2024, AS Unit 2, Q6(d)(ii) (2 marks): Explain why epigenetic changes to genes, such as DNA methylation, are passed on by mitosis. (2)
- June 2024, AS Unit 2, Q5(a)(ii) (2 marks): Explain how these alleles can produce fruit flies with different coloured eyes. (2)
- June 2024, AS Unit 2, Q5(c) (5 marks): Histone modification can affect gene expression, as shown in the diagram. Key Me Me Me Me Histone methylation Histones Me Gene switched off Histone acetylation A
- June 2024, Unit 4, Q8(b)(i) (1 mark): The two horizontal lines in bold show the middle values for each set of the volumes of spleen. Which of the following is the term that describes the middle valu
- June 2024, Unit 4, Q8(b)(ii) (2 marks): Describe two conclusions that can be made from this data. (2)
- January 2024, AS Unit 2, Q3(c)(i) (1 mark): State what is meant by polygenic inheritance with reference to this phenotype. (1)
- January 2024, AS Unit 2, Q3(c)(ii) (2 marks): Sketch a labelled graph to show the expected egg laying rate for a population of hens. (2)
- January 2024, Unit 5, Q5(b)(i) (1 mark): Which is the role of histones in the cell? (1) A act as a transcription factor B form pores in the nuclear membrane C give structural support for DNA molecules
- January 2024, Unit 5, Q5(b)(ii) (1 mark): Which is the process that regulates gene expression? (1) A crossing over B epigenetic changes C post‑transcriptional changes D post‑translational changes
- January 2024, Unit 5, Q5(c)(i) (3 marks): Explain why these changes in the chromosome of this individual would cause Prader–Willi syndrome. (3)
- June 2023, AS Unit 2, Q2(a) (1 mark): There is more than one version of each of the genes involved. Which term is used for different versions of a gene? (1) A allele B locus C phenotype D polygenic
- June 2023, AS Unit 2, Q4(c) (5 marks): Structure B contains pluripotent stem cells. Histone modification and DNA methylation are processes that occur when totipotent stem cells develop into pluripote
- June 2023, Unit 4, Q2(a)(i) (2 marks): Calculate the difference in mass between a typical large black bear and a typical small black bear. (2) Answer kg
- June 2023, Unit 4, Q2(a)(ii) (2 marks): Explain why Hank was much larger than typical black bears. (2)
- January 2023, Unit 5, Q4(b) (1 mark): How many of the following statements about epigenetic modification are correct? (1) • It can result in a change in the base sequence of a gene • It can involve
- January 2023, Unit 5, Q4(d) (2 marks): The expression of genes in cancer cells can be regulated by histone modification. DNA that is not being transcribed is tightly wrapped around histone proteins.
- October 2022, AS Unit 2, Q5(a)(i) (1 mark): State what is meant by the term allele. (1)
- October 2022, AS Unit 2, Q5(a)(ii) (1 mark): Which of the following is the genotype of a person who is Rhesus negative for all three genes? (1) A ccddee B ccddEe C CcDdEe D CCDDEE
- October 2022, AS Unit 2, Q5(b) (3 marks): Seed colour in wheat is an example of polygenic inheritance. There are three genes thought to affect seed colour (A, B, C). Each gene has a dominant and recessi
- October 2022, AS Unit 2, Q8(b) (4 marks): Uncontrolled cell division can result in the formation of a tumour. The RB gene is a tumour suppressor gene. The RB protein produced from this gene inhibits tum
- January 2022, AS Unit 2, Q6(a) (6 marks): Explain why there is a large variation in the skin colour of the offspring produced from this cross. Use information from the question, and your own knowledge,
- January 2022, AS Unit 2, Q6(b) (2 marks): Suggest two reasons why individuals that have inherited the genotype AaBbCc, may have a darker skin colour than other individuals with the same genotype. (2) 1
- October 2021, AS Unit 2, Q2(b) (1 mark): The height of a wombat is a result of polygenic inheritance. State what is meant by the term polygenic inheritance with reference to wombat height. (1)
- October 2021, AS Unit 2, Q7(b) (5 marks): In nematodes, histone modification can be passed onto embryos. Enzyme M causes this modification. The diagram shows two experiments that demonstrated this. Expe
- January 2021, AS Unit 2, Q6(a) (2 marks): Sketch a graph to show the distribution for a phenotype showing continuous variation in a population. (2)
- January 2021, AS Unit 2, Q6(b) (4 marks): The presence or absence of teeth in chickens is one example of a discontinuous phenotype. Chicken genomes contain the genes for tooth production, but chickens d
- January 2021, AS Unit 2, Q6(c) (3 marks): The photograph shows two Himalayan goats. (Source: © Rainer Pauschert / Alamy Stock Photo) The fur colour of a goat depends on its genotype. Gene B controls fur
- January 2020, AS Unit 2, Q3(a)(i) (2 marks): State what is meant by the term polygenic inheritance. (2)
- January 2020, AS Unit 2, Q3(a)(ii) (1 mark): Which of the following graphs represents the distribution of mass of these beans? (1) A Mass B Mass C Mass D Mass
- January 2020, AS Unit 2, Q3(b)(i) (1 mark): A woman with a height of 1.59 m has a daughter. The father is 1.76 m tall. Calculate the predicted adult height of their daughter. (1) Answer m
- January 2020, AS Unit 2, Q3(b)(ii) (3 marks): Explain why their daughter may not grow to be this height. (3)
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