DNA and RNA Flashcards
(53 cards)
people involved with semi conservative dna replication
meselson and stahl
what is semi conservative dna replication
(copying process of dna) half old dna half new dna for each cell
cell cycle
g1-s-g2-m
what is the arrangement of the two polynucleotides in dna
antiparallel
what is the direction of synthesis
5-3
what is helicase
unzips helix (unwinds dna) and breaks hydrogen bonds
DNA polymerase discoverer
kornberg, won nobel prize
describe dna polymerase
(copies the dna): binds and adds complementary nucleotide & repeats (making the strand on opp side) it follow helicase
what are okazaki fragments
a gap on the lagging strand without a phosphodiester bond
what does ligase do
(seals fragments on the lagging strand) creates phosphodiester bind between okazaki fragments
what happens in g1
growing and regular functions
what happens in s of interphase
synthesis, where the replication takes place. 46 to 92 chromosomes
what happens in g2
growth phase, preparing to divide
what are DNA repair proteins
fix mutations in the strand and chops of mutated strand to allow dna polymerase to come and fix it
what is apoptosis
“cell suicide” if dna is damaged, will pick up signal and programs cell death
where does apoptosis take place
mitochondria
mutation
permanent change that passes repair and apoptosis
what are most mutations caused by
random copying mistakes
3 other causes of mutations
radiation, chemicals, infectious agents
how do cells deal with copying mistakes during replication
dna repair, apoptosis
benefits of not having a perfect dna replication system
evolution and variety; adaptation
normal use of apoptosis in the body
shape of organs
if no apoptosis, example of something that could happen
auto-immune disease, brain growing out of head, tumor
what organelle does transcription take place in
nucleus
