mutations Flashcards
1
Q
what is a mutation?
A
alteration to the DNA base sequence
2
Q
what is a mutagen?
A
something that increases the rate of gene mutation
3
Q
why might an amino acid not lead to a change in the amino acid sequence?
A
● genetic code is degenerate so mutation may end up coding for same amino acid as original codon (protects against substitution mutation)
● mutation may occur in intron
4
Q
what is a substitution mutation?
A
nucleotide in DNA sequence is replaced by another
5
Q
what is a deletion mutation?
A
● nucleotide in DNA sequence is lost
● more likely to be harmful / significant
● as it leads to frame shift
● which means entire amino acid sequence will be different
6
Q
what is a nonsense codon?
A
a premature stop codon
