1.6 Mutations Flashcards
What is a mutation?
Changes in the DNA that can result in no protein or an altered protein being synthesised
What is a single gene mutation?
An alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides (SID)
What are the three pathways of a nucleotide substitution?
Missense, nonsense and splice-site mutations
What happens in a missense mutation?
Results in one amino acid being changed for another, this may result in a non-functional protein or have little effect on the protein
What happens in a nonsense mutation?
Results in a premature stop codon being produced which results in a shorter protein
What happens in a splice-site mutation?
Results in some introns being retained and/or some exons not being included in the mature transcript
What is the pathway of a nucleotide insertion or deletion?
Frame-shift mutations
What is a frame-shift mutation?
Causes all of the codons and all of the amino acids after the mutation to be changed. This has a major effect on the structure of the protein produced
What are the 4 types of chromosome mutations?
Translocation, inversion, duplication and deletion (TIDD)
What is translocation?
Where a section of a chromosome is added to a chromosome, not it’s homologous partner
What is inversion?
Where a section of a chromosome is reversed
What is duplication?
Where a section of a chromosome is added from its homologous partner
What is deletion?
Where a section of a chromosome is removed
What is the effect of a chromosome mutation?
The substantial changes in chromosome mutations often make them lethal
Why are mutations and gene duplication in evolution important?
Duplication allowed potential beneficial mutations to occur in a duplicated gene whilst the original gene can still be expressed to produce its protein
