Mutagenesis Flashcards
What does a change in genetic code result in?
Different amino acids being coded for
What does a change in primary sequence result in?
Change in shape, and therefore function, of a protein
What are point mutations?
Base mutations - transition or transversion (silent, missense, nonsense if in the coding region of the protein)
What is the result of a point mutation that is not in the coding region of a protein?
Alteration of binding sites, promoter sequences, splice sites etc
What is a frameshift mutation?
Addition or subtraction of nucleotides not in multiples of 3
What is a silent mutation?
A mutation that doesn’t alter the amino acid specified and thus doesn’t alter the sequence
What is a missense mutation?
A mutation that replaces one amino acid with another
What is a nonsense mutation?
A mutation that changed the amino acid specified to a stop codon
What is a spontaneous mutation?
Not caused by exposure to a known mutagen, errors in DNA replication, DNA bases have slight chemical instability
What determines the rate of spontaneous mutations in genes?
Size and sequence
What are induced mutations?
Mutations cause by chemicals (mutagens) or cancers caused by chemicals (carcinogens)
What do alkylating agents do?
Remove a base
What do acridine agents do?
Add or remove a base
What do X-rays do?
Break chromosomes/delete a few nucleotides
What does UV do?
B- produces vitamin D, B/C - destroy vitamin A, A/B/C - damage to collagen fibres. Creates thymidine dimers
