Overview of DNA replication Flashcards
What is a germ cell? why is it significant?
transmit genetic info from parent to offspring; contains heritable info, therefore if there is a mutation in DNA it will affect offspring.
what is a somatic cell? why is it significant?
cells that form the body; mutations that occur in these cells only affect the body not the offspring
what is a mutation?
permanent change in DNA
what is a replication fork? how is it formed?
active region of replication; formed as helicase unwinds the strands.
what does DNA polymerase do?
recognizes RNA primers and makes the fragments
what is a leading strand?
strand that is continuously synthesized by DNA polymerase (quicker)
what is a lagging strand?
synthesized discontinuously in fragments
what does DNA primase do?
adds RNA primer
what does DNA ligase do?
joins new okazaki fragments to the growing strand
in what direction is DNA built?
5’ - 3’
what does helicase do?
unwinds DNA and breaks hydrogen bonds
what does topoisomerase do?
keeps DNA double strand from becoming tangled as it unwinds
what are okazaki fragments?
fragments that make up the lagging strand; synthesized discontinuously
what is the pre-replicative complex?
a protein complex that forms at the origin of replication during the initiation step of DNA replication
what does telomerase do? what kind of activity does it have?
replicates the ends of the chromosomes; reverse transcriptase
what does pol y (gamma) do? what family does it belong to?
replicates and repairs mitochondrial DNA; family A
what does pol a (alpha) do? what family does it belong to?
forms complex with pol subunits to act as primase (synthesizing an RNA primer) then elongates that primer and starts the process; family B
what does pol (delta) do? what family does it belong to?
exonuclease function; involved in lagging strand synthesis; takes over from Pol alpha (a); family B
what does pol (epsilon) do? what family does it belong to?
exonuclease function; synthesizes the leading strand, corrects errors; family B
what does pol B (beta) do? what family does it belong to?
DNA repair (base-excision and gap-filling); family X
what does pol (lambda and mu) do? what family does it belong to?
non-homologous end-joining repair; family X
what does pol n, I, K (eta, iota, kappa) do? what family does it belong to?
translesion synthesis; not best at incorporating correct base, will replicate through damaged DNA
