Chapter 5 - Gene mutations Flashcards
1
Q
What are two words to describe gene mutations?
A
natural and spontaneous
2
Q
What are mutagens?
A
physical or chemical factors that increase the rate of mutation
example: exposure to radiation and toxins
3
Q
What are point mutations?
A
- A change to a single pair of nucleotides in a DNA sequence
- nucleotides can be swapped or substitued
4
Q
What is another name for point mutations?
A
Substitution mutations
5
Q
What does substitution mutation usually affect?
A
Affects the single amino acid the mutated triplet codes for
6
Q
What are frameshift mutations?
A
- frameshift mutations affect the reading frame of the mRNA
- the reading frame determines where each triplet starts and finishes
- shifting the reading frame alters the amino acid sequence
7
Q
What are the two ways which the reading frame is altered?
A
Insertion mutation
Deletion mutation
8
Q
What is insertion mutation?
A
adds nucleotides to the sequence
pushes the reading frame towards the 3’ end
9
Q
What is deletion mutation?
A
removes nucleotides from the sequence
pushes the reading frame towards the 5’ end
