Lecture 18 - Effects of mutations

Question 1

What is a point mutation?

Answer 1

When one base pair is replaced with another

Question 2

What is a transition point mutation?

Answer 2

When the base replaced is the same group, eg purine to purine

Question 3

What is a transversion point mutation?

Answer 3

When the base replaced is in a different group, eg purine to pyramidine

Question 4

What is a synonymous mutation?

Answer 4

When the point mutation has no effect on the amino acid sequence

Question 5

What is a non-synonymous mutation ?

Answer 5

When the mutation changes the amino acid sequence

Question 6

What is a non-sense mutation?

Answer 6

When the codon for an amino acid is changed into a stop codon

Question 7

What is a readthrough mutation?

Answer 7

When a stop codon is changed into an amino acid codon

Question 8

What is a frameshift mutation?

Answer 8

When a mutation means all codons downstream of it are changed

Question 9

What is an insertion mutation?

Answer 9

One or more base pairs are added to the sequence

Question 10

What is a deletion mutation?

Answer 10

One or more base pairs are deleted from the sequence

Question 11

What is an inversion mutation?

Answer 11

Two or more base pairs are excised and reinserted in the opposite orientation

Question 12

How do we reverse the effect of a mutation?

Answer 12

Through second site reversion
A second mutation restores the correct amino acid sequence
But the nucleotide sequence is still altered