Key Area 1.2 DNA replication Flashcards
What are the requirements for DNA replication?
DNA template Enzymes Primers ATP Fee DNA nucleotides
What is the first thing that happens in stage 1 of DNA replication?
Hydrogen bonds break
What is a primer?
A primer is a short strand of nucleotides needed to start DNA replication
What end of the strand does the primer bind too?
3’ end (3 prime end)
What are the 2 strands in replication called?
Leading and lagging strand
What is the difference between the leading and lagging strand?
The leading strand has a free 3’ end and the lagging strand has a free 5’ end
What happens during replication at the leading strand?
DNA is replicated by the enzyme DNA polymerase, new nucleotides are added to the pre existing chain.
What way can DNA polymerase add nucleotides?
3’-5’
How is the leading strand said to be replicated?
Continuosley
What happens during replication at the lagging strand?
As DNA polymerase is only able to add nucleotides from the 3’ end the lagging strand is replicated in fragments, these fragments are then joined together by ligase.
How is the lagging strand said to be replicated?
Discontinuously
What are the 2 enzymes used in DNA replication called?
Ligase and DNA polymerase
What is the purpose of PCR?
PCR is a technique for the amplification of DNA
What are the requirements for PCR?
A sequence of DNA (template)
Primers
DNA nucleotides
Heat tolerant DNA polymerase
What is the first step in PCR?
The DNA is heated to between 90-98*C to break the hydrogen bonds between the 2 DNA strands separating them.
