Nucleic Acids and DNA Replication Unit 1.4

Question 1

Why is DNA replication considered to be semi-conservative

Answer 1

Each DNA molecule contains:

• One strand from the original
• One new strand

Question 2

What is the role of DNA helicase in semi-conservative replication

Answer 2

• Seperates the two strands

- Breaks hydrogen bonds

Question 3

What is the role of DNA polymerase in Semi-conservative DNA replication

Answer 3

• Joins adjacent DNA nucleotides

- Forms phosphodiester bonds

Question 4

What are the steps in semi-conservative DNA replication

Answer 4

1: The double helix unwinds
2:DNA helicase separates the stands - hydrogen bonds between complimentary bases broken down
3:New nucleotides are attracted to the exposed complimentary bases on the template strand- hydrogen bonds form because of
attractions
4:DNA polymerase enzyme joins adjacent nucleotides using a condensation reaction. This forms the sugar phosphate backbone joined by phosphodiester bonds