DNA replication topic 2.7

Question 1

Semi-Conservative

Answer 1

DNA replication is semi-conservative – one strand is from an original template molecule and one strand is newly synthesised
* This occurs because each base will only pair with its complementary partner and thus ensure the sequence is conserved

Question 2

Helicase:

Answer 2

• Unwinds and separates the double stranded DNA
• Breaks the hydrogen bonds between the base pairs

Question 3

DNA Polymerase III

Answer 3

• Free nucleotides line up opposite complementary partners
• DNA Pol III covalently joins the free nucleotides together

Question 4

Polymerase Chain Reaction

Answer 4

The polymerase chain reaction (PCR) is an artificial method
of DNA replication that is used to rapidly copy sequences

Question 5

PCR occurs in a thermal cycler over three repeating steps:

Answer 5

• Denaturation: DNA heated in order to separate strands
• Annealing: Primers attach to ends of a target sequence
• Elongation: A heat-tolerant polymerase copies strands