AQA A Level Biology (7402) · Paper 2 and Paper 3
AQA A Level Biology 3.8 Control of Gene Expression Exam Questions
Free AQA A Level Biology exam questions by topic for 3.8 The control of gene expression, with a mark scheme for every pack. Covers mutations, stem cells, transcription factors, epigenetics, cancer, genome projects and gene technology.
3.8 Control of Gene Expression exam questions by subtopic
4 question packs covering every part of the specification, with thousands of real past exam questions between them. Do not stop after a few: answer as many as you can, without notes, and mark each one with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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About AQA A Level Biology topic 3.8
Topic 3.8 explains how genes are switched on and off, what happens when that control goes wrong in cancer, and how scientists read, copy and modify DNA. It is often tested with unfamiliar experimental contexts, so practise applying the ideas rather than just recalling them.
What you need to know for 3.8 Control of Gene Expression
- 3.8.1 Gene mutations (addition, deletion, substitution, inversion, duplication and translocation), frameshifts, and mutagenic agents.
- 3.8.2 Totipotent, pluripotent, multipotent and unipotent stem cells and iPS cells; transcription factors and oestrogen; RNA interference; epigenetics (DNA methylation and histone acetylation); and tumour suppressor genes and oncogenes in cancer.
- 3.8.3 Genome projects, the genome and proteome, and why the genome of complex organisms does not easily translate into the proteome.
- 3.8.4 Recombinant DNA technology (reverse transcriptase, restriction endonucleases, the gene machine, PCR, vectors, ligase and marker genes), gene therapy, DNA probes and hybridisation, genetic screening, and genetic fingerprinting.
Common mistakes in 3.8 Control of Gene Expression
- Mixing up oncogenes and tumour suppressor genes. Oncogenes come from proto-oncogenes that become overactive; tumour suppressor genes become inactivated.
- Getting epigenetics backwards. Increased DNA methylation and decreased histone acetylation both reduce transcription.
- Forgetting why a frameshift matters: every codon after the mutation changes.
- Getting PCR temperatures wrong: about 95 C to separate strands, about 55 C for primers to anneal, about 72 C for DNA polymerase.
- Saying genetic fingerprinting compares genes. It compares VNTRs, which are non-coding.
Try three 3.8 Control of Gene Expression exam-style questions
1. Explain how a mutation in a tumour suppressor gene can lead to cancer. (2 marks)
Show the mark scheme answer
The gene is inactivated, so its protein is not produced; cell division is no longer slowed, so cells divide uncontrollably.
2. Explain how oestrogen stimulates transcription of a target gene. (3 marks)
Show the mark scheme answer
Oestrogen diffuses through the cell membrane and binds to a receptor on a transcription factor; this changes the shape of the transcription factor; it can now bind to the promoter region and stimulate transcription.
3. Explain why primers are needed in PCR. (2 marks)
Show the mark scheme answer
Primers bind to the start of the target DNA sequence; DNA polymerase needs a primer to begin adding nucleotides.
Want more? Every pack above has many more past exam questions on control of gene expression.
3.8 Control of Gene Expression FAQs
What does AQA A Level Biology topic 3.8 cover?
Topic 3.8, The control of gene expression, covers mutations, stem cells, transcription factors, epigenetics, cancer, genome projects and gene technology.
Which AQA A Level Biology paper is topic 3.8 on?
Topic 3.8 is examined in Paper 2, which covers topics 3.5 to 3.8. Paper 3 can also include questions on any topic, so it is worth revising for that paper too.
Are these AQA A Level Biology 3.8 exam questions free?
Yes. Every question pack and mark scheme on this page is a free PDF download, with no sign-up needed.
