1.6 mutations Flashcards
what is a mutation?
- changes in the structure and amount of an organisms DNA
- that can result in no protein or an altered protein being synthesised.
- They are spontaneous and random. .
Name the four types of single-gene mutation
- deletion
- insertion
- substitution
what is the impact of a deletion mutation on the amino acid sequence?
- one base is deleted resulting in a shift in “reading frame”
- 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 is the impact of an insertion mutation on the amino acid sequence
- one base is inserted resulting in a shift in “reading frame”
- all codons amino acids after the mutation are changed.
- major effect on the structure of the protein produced - frame-shift
what are the possible results of nucleotide substitutions?
- missense
- nonsense
- spice-site mutations
What do missense mutations result in and what are their effect on the protein?
- one amino acid being changed for another
- may result in a non-functional protein or have little effect on the protein
what do nonsense mutations result in and what is it’s effect on the protein structure?
- premature stop codon being produced
- results in a shorter protein
what do frame-shift mutations result in?
- due to nucleotide insertions or deletions
- all of the codons and all of the amino acids after the mutation are changed
- has a major effect on the structure of the protein produced
what do splice-site mutations result in?
- an intron being retained and/or an exon not being included in the mature transcript
- results in an altered protein which would not function normally
name the 4 chromosome structure mutations
- duplication
- deletion
- inversion
- translocation
What is a duplication mutation?
a section of chromosome is added from its homologous partner, leading to repeated genes
what is a deletion (chromosome structure) mutation?
a section of a chromosome is removed
what is an inversion mutation?
a section of chromosome is reversed
what is a translocation mutation?
a section of chromosome is added to a chromosome that is not its homologous partner
What is the effect of chromosome mutations?
the substantial changes in chromosome mutations often make them lethal