mutations Flashcards
(14 cards)
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
