Scientists studied three variants of the gene for an enzyme. Each variant has one change in the amino acid sequence of the enzyme.
The table shows the results.
Table
| Variant | Position of changed amino acid | Enzyme activity as a percentage of normal |
|---|---|---|
| P | in the active site | 3% |
| Q | far from the active site | 98% |
| R | close to the active site | 41% |
Which conclusion is supported by the data?
Any change in the amino acid sequence stops the enzyme from working.
Changes far from the active site have the largest effect on activity.
Variant Q is in non-coding DNA, so it does not change the enzyme.
The closer the change is to the active site, the lower the activity.
186 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.