DNA Replication Flashcards
Who proved that DNA replicates semiconservatively
Meselson Stahl
What does the process of DNA replication being described as semi-conservative mean
Each daughter duplex has one parental strand (old strand) & one new strand
What is the enzyme that catalyses the polymerisation of deoxyribonucleotides into DNA strand
DNA polymerase
Where can DNA polymerase only add nucleotides to
To the free 3’ OH of the new strand
In what direction does DNA polymerase extend the strand
Strand extends from the starting point in a 5’ to 3’ direction
Why is DNA polymerase referred to as “template dependent”
As it reads the sequence of bases on the template strands & inserts the appropriate complementary base into the new strand
Where does the process of replication begin at in the DNA
At sites in the DNA called origins of replication
What must happen for DNA replication to occur
The double helix must unwind
The process of unwinding the double helix is done by what
helicase enzymes
What does the unwinding of the DNA create
A replication fork exposing two strands of parental DNA
In what way is the leading strand of the replication fork being synthesised
Continuously in the 5’ to 3’ direction as the fork opens
In what way is the lagging strand of the replication fork being synthesised
Discontinuously as short segments of DNA (in 5’ to 3’ direction) that will be joined together to make the completed new strand
What are the short segments of the lagging strand called
Okazaki fragments
For initiation of DNA synthsis, what must be supplied
A DNA primer
What does the primer do
The primer provides the free 3’OH onto which nucleotides are added at the 3’ end
