Gene Mutations

Question 1

What are the three ways a mutation in a gene can occur?

Answer 1

-Insertion
-Deletion
-Subsitution

Question 2

What are the effects of an insertion?

Answer 2

It has a knock on effect of changing the triplets further down the DNA base sequence (know as a frameshift mutation)

Question 3

What are the effects of a deletion?

Answer 3

changes the amino acid that would have been coded for so causes a frame shift

Question 4

What are the effects of a substitution?

Answer 4

This will only change the amino acid coded for by the triplet and will not have a knock on effect (no frame shift). They can take 3 forms:
- silent mutation - does not alter the amino acid sequence
-Missense mutation - a single amino acid is altered
-Nonsense mutation - The mutation creates a premature stop codon so the polypeptide chain will be incomplete

Question 5

what is the lac operon?

Answer 5

an example of a regulatory mechanism