Key Area 6 Flashcards
What is a mutation
Mutations are changes in the DNA that can result in no protein or an altered protein being synthesised.
What is a single gene mutation
A Single Gene mutation involves the alteration of a DNA nucleotide sequence
What do single gene mutations result in
Substitution
Insertion
Deletion
What’s a substitution mutation
These involve one DNA nucleotide being swapped/substituted for another.
Some examples of substitution are
Missense, Nonsense and Splice-site mutations are all examples of substitution mutations.
What’s a miss ensue mutation
Missense mutations result in one amino acid being changed for another. This may result in a non-functional protein or have little effect on the protein.
What does a nonsense mutation result in
Nonsense mutations result in a premature STOP CODON being produced which results in a shorter protein
What do splice site mutations result in
Splice-site mutations result in some INTRONS being RETAINED and/or some EXONS not being INCLUDED in the mature mRNA transcript.
What do insertion mutations involve
Insertion Mutations involve an extra DNA nucleotide being added/inserted into the DNA sequence.
What do deletion mutations involve
Deletion Mutations involve a DNA nucleotide being left out/deleted from the DNA se- quence.
What mutation are frame-shift
Insertion and Deletion
What do frame-shift mutations cause
Frame-shift mutations cause ALL of the codons and all of the amino acids after the mutations to be changed. This has a major effect on the structure of the protein produced.
What’s a chromosome mutation
A Chromosome mutation involves a change in the structure or number of chromosomes.
What are the 4 types of chromosome mutations
Deletion
Inversion
Translocation
Duplication
Explain deletion
This is where a section of chromosome is removed
