Question 13
HScientists studied an enzyme produced by a gene in a species of bacterium.
They found three genetic variants of the gene, V1, V2 and V3. Each variant has a change of one base in the coding DNA of the gene.
The scientists measured the activity of the enzyme produced by each variant.
The Figure shows their results.
Figure
a.[1]
Calculate the percentage decrease in enzyme activity for V3 compared with the normal enzyme.
b.[2]
Suggest why the change in V1 has no effect on the activity of the enzyme.
c.[3]
Explain why the enzyme produced by V3 has very low activity.
3.2 DNA and protein synthesis Questions
44 exam-style questions on Edexcel GCSE Biology 3.2 DNA and protein synthesis, covering 3.2.1 DNA structure as a polymer, 3.2.2 Genome and gene definitions, 3.2.3 Extracting DNA from fruit, 3.2.4 Base order determines protein shape, 3.2.5 Stages of protein synthesis, 3.2.6 Non-coding DNA variants affecting phenotype, and 3.2.7 Coding DNA variants affecting phenotype. Each one has a worked solution and a mark scheme showing where the marks go.