DNA Replication Written Exam .
DNA replication steps
1) Helicase- unwinds the parental double helix
2) DNA topoisomerase - upstream of helices
... [Show More] alleviating torsional strain
3) Single-strand binding proteins (SSBP) stabilize unwound DNA, aided by DNA gyrase (topoisomerase).
4) Primase synthesizes a short RNA primer for DNA polymerase to bind to in the 5' to 3' direction to start replication on each strand.
5) DNA polymerase synthesizes the leading strand in 5' to 3' direction while the lagging strand is made discontinuously by primase making short pieces and then DNA polymerase extending these to make Okazaki fragments.
6) DNA ligase joins the Okazaki fragments together
semiconservative replication
Method of DNA replication in which parental strands separate, act as templates, and produce molecules of DNA with one parental DNA strand and one new DNA strand
conservative replication
A disproved model of DNA synthesis suggesting that one-half of the daughter DNA molecules should have both strands composed of newly polymerized nucleotides.
dispersive replication
a disproved model of DNA synthesis suggesting more or less random interspersion of parental and new segments in daughter DNA molecules
origin of replication
a particular sequence in a genome at which replication is initiated
replication bubble
Segment of a DNA molecule that is unwinding and undergoing replication.
a region of DNA, in front of the replication fork, where helicase has unwound the double helix
replication fork
A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized.
template strand
The DNA strand that provides the template for ordering the sequence of nucleotides in an mRNA transcript.
leading strand
The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction. [Show Less]