Mutations occur continuously in the cells of all organisms.
Describe what happens to the DNA of a cell when a mutation occurs.
One human cell contains 6.0 × 109 DNA bases. On average, 1 in every 3.0 × 108 of these bases has been changed by a mutation.
Calculate the mean number of changed bases in one human cell.
Most mutations do not change the phenotype of a person. Suggest one reason why.
44 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.