In vivo replication (PCR)

Question 1

Is replicated DNA conservative or semi-conservative?

Answer 1

semi-conservative, consists of one newly synthesised strand and one template strand

Question 2

What does replication require?

Answer 2

enzymes (DNA polymerase) (only works in one direction)
nucleotides (dNTPs)
template (DNA to be copied)
primers (to create double-stranded regions required to initiate polymerisation)

Question 3

Only works in one direction

Answer 3

• leading strand (adding to 3’ prime end) –> direction of synthesis means continuous synthesis possible
• lagging strand = discontinuous because DNA polymerase must add to 3’ end of the newly synthesised strand.

Question 4

Replication process

Answer 4

• topoisomerase = unwinds double helix
• helicase = breaks hydrogen bonds
• DNA primase = makes RNA primers
• DNA polymerase = synthesis of new leading and lagging strands(can be alpha or delta)
• DNA ligase = joins the okazaki fragments (short lengths of DNA from discontinuous synthesis of the logging strand) together.
• double-stranded region of DNA to initiate polymerisation (found by primers)
• nucleotides added to 3’ end -must have OH group