Mutations 1.4 Flashcards
What are mutations
Mutations are changes in the 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 if the substitution, insertion or deletion of nucleotides
What are the three types of single gene mutations
Substitution
Insertion
Deletion
What is substitution
Substitution results in a change that only affect one codon
What are three examples of substitution
Missense mutation
Nonsense mutation
Splice site mutation
What is missense
One nucleotide is changed resulting in one amino acid being changed for another
What is the result of a missense mutation
Non functional protein or have little effect on the protein
What is a nonsense mutation
A stop codon is produced prematurely
What is the result of a nonsense mutation
Protein will be shorter and may be non functional
What is a splice site mutation
Some introns may be retained or some exons excluded
What is a result of a splice site mutation
The correct protein may not be produced
What is insertion
When a new base is added/inserted into the sequence causing a frame shift changing all the amino acids
What is deletion
Removing a nucleotide causing a frameshift which moves the bases causing a change in all the amino acids
What is a frameshift
When a base gets added/removed and all the bases move causing a change in all the amino acids
What is chromosome structure mutations
Chromosome structure mutations are alterations that affect whole chromosomes and whole genes rather than just individual nucleotides
What are the four types of chromosome structure mutation
Translocation
Inversion
Deletion
Duplication
What is translocation
A section of one chromosome breaks off and becomes attached to another chromosome that is not its matching partner
What is an effect of translocation
Non viable gametes
What is inversion
A segment between the two breaks and rotates through 180 degrees
Chromosome with reversal of normal sequence of genes
What is an affect of inversion
Haemophilia - produces a clotting factor
What is deletion (in chromosome mutations)
Chromosome breaks in two pieces and the segment in between becomes detached
Shorter chromosome that lacks certain genes
What affect does deletion in chromosome mutations have
Development delays
Learning disabilities
What is duplication
Chromosomes with a set of genes repeated
What affect does duplication have
Cancer
