U1 KA6 Flashcards
1
Q
What occurs in a single gene mutation?
A
- the alteration of a DNA nucleotide sequence.
1
Q
What is a mutation?
A
- changes in the DNA sequence of an organism that can result in no protein, or an altered protein being synthesised.
2
Q
Give 3 examples of single gene mutations.
A
- Substitution
- Deletion
- Insertion
3
Q
What occurs in a Substitution mutation?
A
- one nucleotide is replaced by another.
4
Q
What occurs in a Deletion mutation?
A
- one or more nucleotides are removed from the DNA sequence.
5
Q
What occurs in an Insertion mutation?
A
- one or more nucleotides are added to the DNA sequence.
6
Q
What are the 3 types of substitution mutations?
A
- Missense
- Nonsense
- Splice Site
7
Q
What occurs in a Missense mutation?
A
- one codon is changed into a different one.
- this results in a different amino acid being translated.
8
Q
What occurs in a Nonsense mutation?
A
- one codon is changed into a stop codon.
- this results in a shortened protein being synthesised.
9
Q
What occurs in a Splice Site mutation, and what effect does it have on the organism?
A
- result in some introns being retained and/or some exons not being included in the mature transcript.
- the mRNA may be translated into an altered protein which does not function properly.
10
Q
What causes a frame shift mutation?
A
- Insertion or Deletion mutations.
11
Q
What is the effect of a frame shift mutation?
A
- there is a shift in the organisms base sequence.
- the altered composition can cause different amino acids to be translated.
12
Q
What is a chromosome structure mutation?
A
- when there is an alteration to the structure of one or more chromosomes.
- these substantial changes to the genome can be lethal.
13
Q
Name all 4 chromosomes structure mutations.
A
- duplication (a section of the chromosome is duplicated).
- deletion (a section of the chromosome is deleted).
- inversion (a section of the chromosome is inverted).
- translocation (the section of one chromosome is given to the other one).
14
Q
How do mutations aid evolution?
A
- mutations are a source of new alleles allowing variation.
