SB3e Genetic variants and phenotypes

Question 1

Describe what a mutation is

Answer 1

A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light

Question 2

Recall some ways in which mutations

occur.

Answer 2

A mutation may be neutral and have no effect.
A mutation may sometimes be beneficial.
Some mutations can be harmful. A change in the gene might produce a faulty or non-functioning protein,

Question 3

Describe possible effects of mutations on amino acid sequences.

Answer 3

it may result in shorter or longer codon.

Question 4

Describe how gene transcription is

regulated.

Answer 4

controlled by limiting the amount of mRNA that is produced from a particular gene

Question 5

Explain the effects of mutations on protein

activity

Answer 5

Mutations could cause a different or faulty protein to be synthesised . For example, if the protein is an important enzyme, the specific substrate might not fit into the substrate binding site.

Question 6

Explain how mutations can influence RNA
polymerase binding and so alter protein
production.

Answer 6

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