Topic 7 - Mutations (Paper 2)

Question 1

what do mutations do to DNA?

Answer 1

mutations change the sequence of the DNA bases in a gene, which produces a genetic variant

Question 2

how can mutations change enzymes?

Answer 2

enzymes are protiens which need an active site with a very specific shape to be able to work properly. a mutation can lead to a change in the shape of an enzymes active site, altering its function.

Question 3

what effect do mutations have on phenotypes?

Answer 3

most mutations do not affect the phenotype - if they occur in an unimportant region of DNA or if they code for the same amino acid
some mutations have a small effect on the phenotype - when the change in amino acid only has a slight effect on the structure and function of the protein
few mutations have a significant effect on the phenotype - if the protein is very different and cant carry out the function. this can be harmful or beneficial

Question 4

how is the chance of mutation increased?

Answer 4

exposure to ionising radiation or mutagens