Practise 43 exam-style questions on Genetic engineering for AQA GCSE Biology. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
43 questions
3–4 marks each
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20 questions, marked as you go
Sample questions with model answers
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
Question 1
3 marks
Define genetic modification (modifying the genome) and distinguish it from selective breeding.
Model answer
Genetic modification: directly altering an organism's genome by inserting, deleting or changing genes (often from another species). Selective breeding: choosing parents with desirable traits to breed over generations — does not involve direct insertion of genes.
Explanation
GM changes the DNA directly and precisely, sometimes across species, whereas selective breeding exploits natural variation across generations without direct gene transfer.
Mark scheme
1 mark
Genetic modification: direct alteration/introduction of genes into genome
1 mark
Often involves transfer of genes between species / precise genetic change
1 mark
Selective breeding: choosing parents with desired traits over generations (no direct gene insertion)
Question 2
3 marks
Give one scientific reason and one socio-economic reason some people object to GM foods.
Model answer
Scientific: potential long-term ecological impacts or unknown health effects (insufficient long-term data). Socio-economic: corporate control of seed supply, increased costs or dependency of farmers on patented seeds.
Explanation
Concerns include scientific uncertainties about ecological and health impacts and socio-economic issues like seed patenting and effects on smallholder farmers and biodiversity.
Mark scheme
1 mark
Scientific reason: unknown/long-term health or ecological impacts / gene flow / resistance evolution
1 mark
Socio-economic reason: corporate control of seeds, patents, farmer dependence or market domination, cost issues
1 mark
Explanation linking to consequences (e.g., farmer debt, loss of traditional seeds)
Question 3
4 marks
Explain why bacteria transformed with a plasmid containing a human gene may not produce the human protein correctly. Give TWO reasons.
Model answer
Bacteria lack eukaryotic post-translational modification (e.g., glycosylation); differences in codon usage; human genes may have introns that bacteria cannot splice out; protein may fold incorrectly or form inclusion bodies.
Explanation
Despite being able to express foreign genes, bacteria cannot perform some eukaryotic processing, may not correctly splice introns, and codon/folding differences can prevent proper function of human proteins.
Mark scheme
1 mark
No eukaryotic post-translational modifications (e.g., glycosylation) in bacteria
1 mark
Human gene may contain introns which bacteria cannot remove (no splicing)
1 mark
Different codon usage / translation efficiency limits expression
1 mark
Protein folding problems / inclusion bodies / wrong disulfide bonds
Question 4
4 marks
Describe two laboratory methods to confirm that a gene has been correctly inserted into a plasmid (molecular confirmation).
Model answer
Restriction digest mapping (cut plasmid with restriction enzymes and check fragment sizes by gel electrophoresis); PCR with primers flanking insert and sequencing of PCR product (Sanger sequencing) to verify sequence and orientation.
Explanation
Molecular confirmation methods include restriction mapping, PCR, and sequencing, which verify presence, size and exact sequence of the inserted gene in the plasmid.
Mark scheme
1 mark
Restriction digest and gel electrophoresis to check fragment sizes correspond to expected insert
1 mark
PCR with insert-specific primers to amplify presence/size of insert
1 mark
DNA sequencing (Sanger) to confirm correct sequence and orientation
1 mark
Colony hybridisation / southern blot with probe for insert as alternative
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