DNA replication Flashcards
(12 cards)
When does DNA replication occur?
Cell division
What is the first stage of DNA replication?
DNA helicase breaks hydrogen bonds and separates the polynucleotide strands
What does each strand act as?
A template for the formation of two new complimentary strands
What is the second stage of DNA replication?
Individual nucleotides attach with hydrogen bonding by complementary base pairing
How do the bases pair?
Adenine and thymine, guanine and cytosine
What is the third stage of DNA replication?
DNA nucleotides joined together by phosphodiester bonds in condensation reaction
What is the enzyme that catalyses DNA replication?
DNA polymerase
What does DNA replication create?
Two DNA molecules that are identical to each other
What does semi-conservative mean?
Each new molecule contains one of the original strands and a new strand
Who proved the semi-conservative theory of DNA replication?
Meselson and Stahl
What was the method used by Meselson and Stahl?
The normal 14 N isotope was replaced with 15 N
How did Meselson and Stahl’s method prove that DNA was semi-conservative?
The centrifuged product contained isotopes from 14 N and 15 N
