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Practise 34 exam-style questions on DNA and the genome 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.
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.
What was the Human Genome Project?
An international research effort to sequence the entire human genome (determine the order of bases in human DNA) and map all genes.
The HGP produced the first reference sequence of human DNA, identifying and mapping many human genes.
project to sequence / map the entire human genome
determine order of DNA bases / identify genes
Why is peer review important when publishing claims about new genomic tests or drugs?
Peer review checks the methodology and conclusions for validity and reduces bias or errors, increasing confidence in results before clinical use.
Independent critical assessment helps ensure findings are reliable and safe to translate into practice.
checks methods and data (validity) / reduces errors
reduces bias and increases confidence before clinical adoption
Describe how selective breeding (artificial selection) is used to produce desired traits in animals or crops.
Choose individuals with desired traits to breed; select best offspring over several generations; repeat to increase frequency of favourable alleles and fix the trait.
Repeated selection of favourable phenotypes concentrates the underlying alleles in the population, producing improved varieties or breeds.
select parents with desired trait(s)
breed them and select best offspring each generation
over generations increases frequency of favourable alleles / trait
Explain how comparative genomics between species can show evolutionary relationships.
Compare DNA sequences; more similar genomes indicate more recent common ancestry. Conserved genes/functions indicate shared descent; patterns of change show divergence times.
Genomic similarity and conserved sequences reflect evolutionary relationships and can be used to infer phylogeny and divergence times.
compare DNA / gene sequences between species
greater similarity = more recent common ancestry
conserved genes and sequence changes indicate shared descent and divergence
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