Gene mutation

HideShow resource information
  • Created by: LZ95
  • Created on: 05-05-14 11:46
What is a silent mutation?
When a base is substituted but the triplet code still codes for the same amino acid
1 of 16
How can a different triplet code still code for the same amino acid?
Degenerate code- more than one triplet code codes for a single amino acid
2 of 16
How does a silent mutation affect the polypeptide chain formed?
It doesn't - as the mutation still codes for the original sequence of amino acids, there will be no change in the polypeptide chain formed
3 of 16
What is a nonsense mutation?
Where the mutation results in the formation of one of the three stop codons
4 of 16
What are the 3 stop codons in DNA?
TAG, TAA and TGA
5 of 16
How does this lead to the formation of a non-functional polypeptide chain?
The production of the polypeptide chain stops prematurely
6 of 16
What is a mis-sense mutation?
It is a base change that results in a different amino acid being created.
7 of 16
How does this lead to the formation of a non-functional polypeptide chain?
Different sequence of amino acids so the tertiary structure of the polypeptide chain will have changed, making it no longer functional
8 of 16
What is a deletion mutation?
When a nucleotide is lost from the DNA sequence
9 of 16
What effect does this cause?
A frame shift
10 of 16
Explain what is meant by a frame shift and what it does
Bases are read as triplet codes rather than individually so when a base is deleted frame shift happens so the triplet codes change, leading to a different sequence of amino acids
11 of 16
When does a frame shift have the largest effect?
When it happens at the start of a sequence
12 of 16
What do proto-oncogenes do?
Stimulate cell division
13 of 16
What can they mutate to?
Oncogenes
14 of 16
What do oncogenes do?
They cause cell division in the absence of a growth factor by permanently activating a receptor protein and produce a growth factor in excessive amounts
15 of 16
What do tumour suppressor genes do?
Slow down cell division
16 of 16

Other cards in this set

Card 2

Front

How can a different triplet code still code for the same amino acid?

Back

Degenerate code- more than one triplet code codes for a single amino acid

Card 3

Front

How does a silent mutation affect the polypeptide chain formed?

Back

Preview of the front of card 3

Card 4

Front

What is a nonsense mutation?

Back

Preview of the front of card 4

Card 5

Front

What are the 3 stop codons in DNA?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all DNA, genetics and evolution resources »