KA4 - Mutations Flashcards
What is a mutation?
Mutations are changes in DNA that can result in no protein or an altered protein being synthesised
What is a single gene mutation?
Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of substitution, deletion and insertion of nucleotides
What can single gene mutations be a result of?
Substitution
Insertion
Deletion
What is a substitution mutation?
A substitution mutation involves one nucleotide being substituted for another in a DNA sequence
What is an insertion mutation?
An insertion mutation involves one or more nucleotides being added into a DNA sequence
What is a deletion mutation?
A deletion mutation involves one or more nucleotides being removed from a DNA sequence
Substitution mutations affect one codon only. What are the three types?
Missense
Nonsense
Splice-site
What is a missense mutation?
Missense mutations result in one amino acid being changed for another.
What might Missense mutations result in?
Missense mutations may result in a non functional protein or have little effect on the protein.
What is a nonsense mutation?
Nonsense mutations result in a premature stop codon being produced which results in a shorter protein
What might nonsense mutations result in?
A shortened protein is generally non functional or it’s function is affected
What is a splice site mutation?
Splice site mutations can result in some introns being retained and/or some exons not being included in the mature transcript
What might splice site mutations result in?
This may result in a different protein being made
What results in frame shift mutations?
Nucleotide insertions or deletions
What are frame shift mutations?
Frame shift mutations cause all of the codons and all of the amino acids after the mutation to be changed
