Mutations Flashcards
What is a mutation?
A change in an organism’s DNA.
What can a mutation result in?
No protein being synthesised or an altered protein being synthesised.
What is the frequency of mutations?
They are spontaneous and random - tend to be recessive so appear in a low number of the population.
What can cause an increase in mutations?
Mutagenic agents.
What is the effect of mutation on an individual?
Usually has negative effects, however, sometimes they give an advantage to the individual and become a driving factor of evolution.
Gene mutations involve the alteration of what?
A DNA nucleotide sequence.
What are the three types of gene mutations?
- substitution
- insertion
- deletion
What is a gene mutation by substitution?
A single nucleotide is replaced with a different nucleotide.
What is gene mutation by insertion?
A single nucleotide is added into a DNA sequence.
What is gene mutation by deletion?
A single nucleotide is removed from a DNA sequence.
What is a missense mutation?
One amino acid is changed for another resulting in a non-functional protein or it could have little effect on the protein.
What’s a good way to remember missense mutations?
MISsense - MIStake
What is a nonsense mutation?
A codon used to code for an amino acid is changed to stop a codon meaning a short protein will be produced.
How to remember nonsense mutation?
Stop that nonsense.
What is a frameshift mutation?
Cause all codons and amino acids after the mutation to be changed, creating a major effect on the structure of the protein produced.
What is a splice site mutation?
A mutation at the splice site may cause the codon for the intron or exon to be affected - the intron may be kept or the exon could be cut out.
What are the two types of mutation?
- gene
- chromosome
What are the four types of chromosome mutation?
- duplication
- deletion
- inversion
- translocation
What is chromosome mutation by duplication?
Genes from one chromosome attach to their homologous partner (matching chromosome) leading to repeated genes.
What is chromosome mutation by deletion?
Chromosome breaks in two places and the middle segment is detached. When it rejoins it is shorter and has lost genes.
What is chromosome mutation by inversion?
Chromosome breaks in two and the segment turns around and reattaches, causing the reversal of the normal sequence of genes.
What is chromosome mutation by translocation?
Chromosome section breaks off and attaches to another chromosome that is not its homologous partner.
What in the genes and chromosomes are important for evolution?
Mutations and gene duplication as they are the starting point of evolution.
