U1 - Mutations Flashcards
what is a mutation?
Random and spontaneous changes in genetic material that affect the production of proteins. (2 consequences: no protein is produced or an altered protein is produced)
state the three types of single gene mutation
substitution, insertion, deletion
what is a single gene mutation
when only one nucleotide is altered
state the three types of substitution
missense, nonsense, splice site
explain missense substitution
one amino acid is changed for another. this can result in a non-functional protein or may have little effect on the protein
explain nonsense substitution
a normal codon is replaced by a premature stop codon. may result in an abnormally short codon which cannot function properly
explain splice site substitution
a mutation which occurs at the site of mRNA splicing. can result in some introns being retained / some exons lost. may result in a non-functioning protein
describe the effect of frame shift mutations
causes all of the codons and amino acids following the mutation to be altered
what are chromosome structure mutations?
mutations which alter the number or order of genes on a chromosome
explain translocation
a section of chromosome is added to another chromosome which is not its homologous partner
explain inversion
a section of chromosome is reversed
explain deletion
a section of chromosome is removed
explain duplication
a section of chromosome is added to another chromosome which is its homologous partner
describe the importance of mutations in evolution
mutations are the only source of new alleles and therefore the only source of variation
What is polyploidy
Polyploidy is a condition in which an individual has sets of chromosomes greater than the normal diploid number
