Replication of DNA

Flashcards by , created about 6 years ago

AS Biology2 (The Cell Cycle) Flashcards on Replication of DNA, created by sammi_taylor01 on 05/29/2013.

Created by sammi_taylor01 about 6 years ago
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Question Answer
What are the two main stages of cell division? nuclear division and cell division
What must occur before a cell divides? It's DNA must be replicated in order for the daughter cells to contain enough genetic information to produce enzymes and other substances they may need.
Why is DNA semi-conservative? 50% is from the original DNA strand and 50% is from a new DNA strand
What type of bonds are between the four organic bases hydrogen bonds between A and T as well as between G and C
What enzyme is used to break down the hydrogen bonds and which enzyme is used to put them base pairs together again? DNA helicase- unzips the genes DNA polymerase- puts the genes back together
Explain the steps to DNA replication. helicase breaks down hydrogen bonds, double helix separates, polynucleotide strand is then joined with other nucleotides via DNA polymerase to form 50% new and 50% original strand.
If an inhibitor of DNA polymerase were introduced into a cell, explain what the effect would be on DNA replication. The linking together of new nucleotides could not take place. While the nucleotides would match up to be complementary, they would not join together to form new strands.
What's the evidence for semi-conservative replication Watson and Crick used DNA that contained Nitrogen- some 14N and some 15N
Why was bacteria chosen to be used for this experiment? It divides rapidly and you can extract their DNA easily (via centrifugation)
What happens with the medium containing 14N and 15N bacteria 14N is light so will float 15N is heavier so will be closer to the bottom
What happens when 14N and 15N grow and allow to replicate once? They are bound together and form in between where the 15N and the 14N formed.