mutations Flashcards
what are mutations?
changes in the DNA that can result in no protein or an altered protein being synthesised.
what are single gene mutations?
the alteration of a DNA nucleotide sequence for example, substitution, insertion or deletion of nucleotides.
what are the 3 types of
Nucleotide substitutions
missense, nonsense and splice-site mutations.
describe a missense mutation
one amino acid being changed for another. This may result in a non-functional protein or have little effect on the protein.
describe a nonsense mutation
result in a premature stop codon being produced which results in a shorter protein.
describe a splice-site mutation
result in some introns being retained and/or some exons not being included in the mature transcript.
what do nucleotide insertions or deletions result in?
frame shift mutations
what do
Frame-shift mutations cause?
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 they types of chromosome mutations?
duplication, deletion, inversion and translocation.
describe a duplication mutation
where a section of a chromosome is added from its homologous partner.
describe a deletion mutation
where a section of a chromosome is removed.
describe a inversion mutation
where a section of chromosome is reversed.
describe a translocation mutation
where a section of a chromosome is added to a chromosome, not its homologous partner.
what is the importance of mutations and gene duplication in evolution.
Duplication allows potential beneficial mutations to occur in a duplicated gene whilst the original gene can still be expressed to produce its protein
