lecture 12 - DNA replication Flashcards
What are the 2 strands called in DNA synthesis.
leading and lagging
Which enzyme unwinds the DNA to give two parental templates.
helicase
What is the enzyme that makes an RNA primer called.
primase
Which enzyme synthesises a new DNA strand by adding nucleotides complementary to the parental template strand.
DNA polymerase III
The release of tension generated by unwinding DNA is by which enzyme?
topoisomerase
What are some functions of the single-stranded DNA binding protein.
prevent unwounded DNA from reforming and to protect it from degrading
Which enzyme removes RNA primer and fills gap with DNA nucleotides.
DNA polymerase I
What is the function of DNA ligase.
joins ends of replication bubbles, as well as the okazaki fragments in the lagging strand
When can DNA errors be repaired .
during: exonuclease
after: endonuclease
How do DNA errors repair during DNA replication.
DNA polymerase III has a proofreading mechanism so incorrect bases nuclease are removed by a 3’5’ exonuclease activity
How do DNA errors repair after DNA replication.
the region with the incorrect pair is removed by an endonuclease, a DNA polymerase makes new DNA and DNA ligase joins it together
What are the 3 steps in PCR.
denaturation, annealing, extension
What occurs in denaturation.
temperature is increase 94-98 degrees to separate DNA strands (acts as helicase)
What occurs in annealing.
temperature is decreased to 45-70 degrees to allow DNA primers to base pair complementary DNA template
What occurs in extension.
polymerase extends primer to form nascent DNA strand
