Mutations and Cancer. Flashcards
mutations can occur at which level?
at the chromosomal level or the nucleotide level.
a mutation in a germ cell is serious . why?
germ cells give rise to many cells ! can be very serious for offspring as well.
mutations can be spontaneous and …
induced! - caused by mutagens.
what is a point mutation?
if a mutation changes a single base pair of nucleotides
base pair substitution mutation?
when one base pair is replaced by another!
transition mutation
sub a purine for a purine
transversion mutation
sub a purine for a pyrimidine
what is a missense mutation?
base pair mutation that occurs in the aa coding seq of a gene. a missense mutation may or may not alter the aa sequence of a protein , and an alteration of a single aa may or may not have serious effects on the function of the protein.
neutral mutation
if there is no change in protein function
silent mutation
if the aa is not changed.
frameshift mutation
can be caused by an insertion or deletion of a base pair
normally if they occur in multiples other then 3
- frameshift mutations often result in a completely non functional protein, whereas nonframeshift mutations may still result in a partially or even completely active protein.
nonsense mutation
if a base pair substitution or an insertion or deletion mutation creates a stop codon.
these are very serious bc they prevent translation of a functional protein
chromosomal mutations
structural changes may occur to a chromosome in the form of deletions, duplications, translocations and inversions
what are transposons and transposable elements?
DNA segments called transposable elements or transposons can excise themselves from a chromosome and reinsert themselves at another location.
forward mutation or a backward mutation
term refers to an already mutated organism that is mutated again.
backward is reverting the organism back to its original state.
