Mutations Flashcards
what is a mutation
changes in DNA that MAY OR MAY NOT affect phenotype
what are the 2 causes of mutations
- spontaneous
- arise from errors in replication - induced
- forced by mutagens
what is a mutagen
an agent that DIRECTLY causes mutations
- carcinogens, radiation
what are the common causes of DNA mutation
- base mismatch
- single-strand break
- double strand break
- interstand crosslinks
- bulky adducts/intrastrand crosslinks
what are germ line cells
cells that become gametes
what happens if a mutation occurs in a germ line cell? what is that mutation called
gametic mutation
- significant in germ line cells because it is passed down to offspring
- new allele can be created
what is an allele
a gene or different version of a gene that gives you different amino acid sequence
what type of mutations cannot be passed down
somatic mutations
- occur in NON SEX cells (body tissues)
what are the types of mutations
- point mutations
- chromosomal mutations
point mutations
occur and involve only a SMALL number of NUCLEOTIDES
- substitutions
- insertions/deletions
chromosomal mutations
- deletions of BIG CHUNKS of CHROMOSOMES
- chromosomes swapping sections
- inversions…can make a new dna
what are the outcomes of mutations
- silent
- missense
- nonsense
silent mutation
no change to amino acid sequence
missense
- conservative: amino acid seq properties conserved (dont change)
- non polar a.a switched with another non polar a.a (wont change much, conformation will be the same) - nonconservative: a.a seq properties changed
- non polar a.a switched with polar a.a
- conformation changes
nonsense
early STOP codon
- protein doesnt really do anything
