dna replication Flashcards
why are the 2 strands of dna complementary?
if you know half of it, you know the rest. Each strand has the info to construct the other.
Why is DNA semiconservative?
each new molecule is composed of one NEW strand and one OLD strand from og molecule
why are the strands of DNA antiparallel?
the strands are side by side , but replicate in opposite directions
replication is always
5’ to 3’
where does repair and replication begin
begins at origins of replication, creating replication bubbles
what are replication bubbles
where DNA opens up to replicate
first step of replication
DNA helix is unzipped (hydrogen bonds need to open) by helicase enzyme and H bonds are broken
what is helicase
an enzyme that keeps helix open for new dna to be added
second step
single strand binding proteins prevent binding of the unzipped base pairs so they can be a template
what does the second step create
produces replication fork
which produce a new leading strand (5’ end)
and a new lagging strand (new 3’ end)
step 3
DNA polymerase speeds up the addition of new nucleotides to the new strands of DNA
how does replication of the 2 strand occur?
At the same time, one continuously and one discontinuously.
the leading strand is synthesized in the…
same direction as the movement of the replication fork
the lagging strand is synthesized in the…
opposite direction
what is the synthesizing of the lagging strand called
okazaki fragments
how are the short fragments stitched together
with an enzyme called DNA ligase
How does proofreading DNA occur?
DNA polymerase: self correcting enzyme
how are damaged segments cut out?
Nuclease: an enzyme that acts like chemical scissors
