8.2 Flashcards
Define leading strand.
The strand that is continuous.
Define lagging strand.
The strand that is discontinuous.
Define semi-discontinuous.
Something that is both continuous and discontinuous.
Define semiconservative replication.
Replication where the helicase splits the DNA in half, then other enzymes attach nucleotides to the two separated strands to replicate it.
Define okazaki fragments.
The fragments made by the lagging strand each time it has to go back.
What does the helicase do?
The helicase breaks hydrogen bonds connecting the two DNA strands to begin replication.
What does the DNA polymerase I do?
DNA polymerase I replaces the RNA primers with nucleotides.
What does the DNA polymerase III do?
DNA polymerase III attaches nucleotides to the separate strands.
What does the ligase do?
The ligase attaches the okazaki fragments back together.
What does the primase do?
The primase puts RNA primers in the front of the DNA strands.
What is the order of events in DNA replication?
What was Meselson and Stahl’s experiment?
Meselson and Stahl’s experiment was about figuring out how DNA replication happened. They put heavy nitrogen with an extra neutron in DNA, then they added light nitrogen. Since the replication is semiconservative, most of the DNA went to the top of the liquid as they became fully lighter nitrogen, while a couple remained in a medium level of the liquid because they are hybrid strands, half heavy nitrogen and half lighter nitrogen.
