Mutations Flashcards
What are mutations?
Mutations are random changes to genetic material that can result in no protein or an altered protein being synthesised
Single gene mutations involve the alteration of a DNA nucleotide sequence, as a result of what?
Substitution, insertion or deletion of nucleotides
What can a substitution mutation result in?
Silent- no effect on protein sequence
Missense- amino acid substitution
Nonsense- a stop codon is substituted
What does a missense mutation result in?
One amino acid is changed for another
What is the effect of a missense mutation?
A non-functional protein or have little effect on the protein
What does a nonsense mutation result in?
A premature stop codon is produced causing a shorter protein
What is a splice-site mutation?
A mutation which substitutes, inserts or deletes one or more nucleotides at a site where introns are normally removed from the primary mRNA transcript
What does a splice-site mutation result in?
Some introns being retained and/or some exons not being included in the mature transcript
What happens to DNA nucleotides sequence as a result of insertion/deletion?
Causes a frameshift mutation
What is a frameshift mutation?
Because of insertion/deletion cause frameshift mutations.
When the codons are read at the ribosome, the codon reading frame is shifted
What does a frameshift mutation cause?
Causes all of the codons and all of the amino acids after the mutation to be changed. Has a major effect on the structure of the protein produced (maybe a non-functioning protein)
What are chromosome mutations?
Alterations to the structure of one or more chromosomes
Name the 4 types of chromosome mutation?
Deletion
Duplication
Inversion
Translocation
Explain duplication, in terms of chromosome mutation?
A section of a chromosome added from its homologous partner
Explain deletion, in terms of chromosome mutation?
A section of chromosome is removed
