DNA Replication

Question 1

why is DNA replication known as semi-conservative?

Answer 1

as the DNA produced contains a strand of conservative (original) DNA and a new strand of DNA

Question 2

why does DNA replication occur?

Answer 2

so that new cells have the correct amount of DNA

Question 3

describe the process of DNA replication

Answer 3

1. DNA helicase hydrolyses the hydrogen bonds between bases on the two DNA strands, unwinding it
2. Free-floating nucleotides line up with the complimentary bases on the strand, through complimentary base pairing
3. DNA polymerase catalyses the condensation reactions that join the nucleotides of the new strand together
4. Hydrogen bonds form between the bases of the original and new strand
5. Each DNA molecule contains a conservative DNA strand and a new strand

Question 4

what direction do DNA polymerase travel?

Answer 4

• in opposite directions to each other, on a 5 to 3 prime direction
• due to site of polymerase only being complementary at the 3 prime

Question 5

which experiment supports the semi-conservative theory?

Answer 5

Meselson and Stahl’s experiment