DNA Replication

origin of replication

specific DNA base sequence recognized by proteins involved in DNA replication

what bonds link sugar and phosphate backbones of DNA?

covalent bonds

what bonds link the nitrogenous bases?

hydrogen bonds

how many bonds between A/T

2

how many bonds between C/G

3

DNA replication is…

semi-conservative

definition of semiconservative

one strand is the template for the other strand

function of helicase

unwinds 2 DNA strands

function of single stranded binding proteins

stabilize unwound strands

function of topoisomerase

untangles unwound coils by breaking, swiveling, and rejoining DNA strands

function of primase

makes RNA primer where DNA synthesis can begin

function of DNA polymerase

adds nucleotides by dehydration-synthesis reactions

which end does DNA polymerase add bases to?

3’

what direction are new RNA strands made in?

5’ to 3’

leading strands are synthesized…

continuously 5’ to 3’

lagging strands are synthesized…

discontinuously in Okazaki fragments 5’ to 3’

function of ligase

forms covalent bonds between Okazaki fragments

mismatch repair

enzyme (not DNA polymerase) removes and replaces

incorrectly placed nucleotides

excision repair

enzyme removes and replaces damaged region of DNA