Replication of DNA Flashcards
Name the 2 enzymes involved in DNA replication.
DNA polymerase and Ligase
What do we call a short strand of nucleotides?
primers
To which end of the template strand of DNA do primers bind?
3’ end
What is added to the primer by DNA polymerase?
DNA nucleotides
To which end of the new strand are nucleotides added?
3’ end
What is the very first thing that must happen to the DNA molecule during DNA replication?
unwind the double helix
Name the bonds that are broken to separate the two template strands.
hydrogen bonds
What name is given to the strand that can be replicated continuously.
leading strand
What name is given to the strand that has to be replicated in fragments?
lagging strand
Which strand requires DNA polymerase and ligase?
lagging strand
What is the role of ligase?
To join the fragments together
What does PCR stand for?
Polymerase Chain Reaction
What is the purpose of PCR?
To amplify a section of DNA
State 3 practical uses of PCR.
solve crimes, paternity suits and diagnose genetic disorders
What are the 3 key temperatures you need to remember for PCR?
95, 55, 75
What happens when the DNA is heated to 95?
The hydrogen bonds break and the two strands are separated.
What happens during PCR when the temperature drops to 55?
The primers bind with their target sequences.
During PCR, why is it then heated to 75?
Heat tolerant DNA polymerase replicates the region of DNA by adding nucleotides
If you have one strand of DNA at the start, how many will you have at the end of one cycle?
2
If you have one strand of DNA at the start, how many will you have at the end of two cycles?
4
If you have one strand of DNA at the start, how many will you have at the end of three cycles?
8
If you have 100 strands of DNA at the start, how many will you have at the end of one cycle?
200
