Cell structure and function: mutations and cancer Flashcards
Small scale mutation
substitutions - single base replaced
insertions/deletions (indels)- can cause frame shift
types of mutations
germ line - passed to progeny
somatic - local effects, tumors
large - chromosomal rearrangements
small scale - one or few nucleotides
substitutions
silent
missense
nonsense
indels
cause frameshift if 1 or 2 nt
can maintain frame if 3 nt
Silent mutation
single point or base. no effect on protein
Missense mutation
single point and it changed the amino acid, impact depends of the importance of that residue on the protein.
nonsense mutation
not being read so results in truncated protein. Premature stop, impact depends on where stop is
Insertion frame shift
addition causes everything to shift down so codons won’t be read they way they are meant to be read effectively changed the protein entirely
Frame shift via deletion
everything shifts back and codons won’t have their bases read in the threes they were meant to. effectively changed the protein entirely
G2 checkpoint
dictates whether mitosis will start
cyclin and cyclin dependant kinase form a complex called MPF that signals for the mitosis to occur.
Stop/go molecules
stop: keep proliferation in check
go: stimulate proliferation
if mutation, can cause cancer
How do cancer mutations arise
genetic predisposed: all body cells. inherited. issue or deficiency. multiple need to accumulate
acquired: UV damage, carcinogens, cause multiple mutations
–> loss of cell cycle control
Proto -oncogenes
stimulate cell proliferation
become oncogene with mutation = increased function over activatio
tumor suppressor
keep proliferation in check
when deactivated, loss of brakes so inhibitory proteins not created and cell cycle continues when it shouldn’t
