2. Action Of DNA Polymerase

Question 1

Define DNA polymerase.

Answer 1

Enzyme joining together the nucleotides on new strand of DNA during dna replication

Question 2

Define dna helicase

Answer 2

Enzyme breaking hydrogen bonds between 2 polynucleotide dna strands during dna replication

Question 3

How is each end of dna strand different ?

Answer 3

One end is called the 3 prime end and other end called 5 prime end.

Question 4

Why is this significant?

Answer 4

As during dna replication the active site of DNA polymerase is only complementary to 3 prime end of newly forming dna strand so enzyme only add nucleotides to new strand at 3 prime end.

Question 5

So what direction is new strand made in ?

Answer 5

5 prime to 3 prime direction as the DNA polymerase moves down the template strand in a 3 prime to 5 prime direction.

Question 6

What does it mean that the double helix of dna is antiparallel?

Answer 6

The dna polymer made working on one template strand moves in the opposite direction to DNA polymerase working on toner template strand.

Question 7

Why are 3 prime and 5 prime ends different?

Answer 7

3 prime - hydroxyl group that is attached to pentose sugar of nucleotide.
5 prime - phosphate group.