8.1 Altering sequence of bases Flashcards
1
Q
what is a gene mutation?
A
an alteration in the sequence of bases for one gene
2
Q
when are mutations most likely to occur?
A
During DNA replication
3
Q
what can increase the frequency of mutations?
A
mutagenic agents
4
Q
examples of mutagenic agents:
A
- high energy and ionising radiation (x-rays and gamma rays) and carcinogens (e.g. chemicals in tobacco)
5
Q
what are carcinogens?
A
chemicals that can alter the structure of DNA and interfere with transcription
6
Q
what can result from a change in the amino acid sequence?
A
- when the protein is modified into the tertiary structure it will form hydrogen and ionic bonds in different places and fold differently
- results in a different 3D and therefore a non-functioning protein
7
Q
what are the 6 types of mutation?
A
- addition
- deletion
- substitution
- inversion
- duplication
- translocation
8
Q
addition mutation:
A
- one base being added to the sequence of bases
- frameshift mutation
9
Q
Why are frameshift mutations so bad?
A
- altered codons can potentially code for a different amino acid
- results in a non-functioning protein
10
Q
deletion mutation:
A
- the deletion of a base in a sequence
- causes a frameshift to the left
11
Q
substitution mutation:
A
- one base being swapped with another base
- number of bases remains the same - NO frame shift
12
Q
inversion mutation:
A
- a section of bases detach from the DNA sequence, but when they rejoin they are inverted
- results in dif amino acids being coded for in the region
13
Q
translocation mutation:
A
- a section of bases on one chromosome detaches and attaches onto a dif chromosome
14
Q
why are translocation mutations bad?
A
- substantial alteration that can significantly impact gene expression
