DNA Replication

Question 1

Describe DNA replication x7

Answer 1

Enzyme DNA helicase attaches onto DNA molecule
This causes the complementary bases paid to break
Two polynucleotide strands separate
Free (activated) nucleotides line up with complementary base pairs
The nucleotides are only held in place by hydrogen bonds between complementary base pairs (no phosphodiester bonds)
Second enzyme attaches DNA polymerase
Catalyses the formation of phosphodiester bonds between activated nucleotides

Question 2

Difference between normal nucleotides and free nucleotides
(+name)

Answer 2

Activated nucleotides
Contains three phosphate groups (normally only one)

Question 3

What does DNA polymerase do

Answer 3

Moves down the molecule and catalyses the formation of a phosphodiester bond between the activated nucleotides

Question 4

What type of reaction does DNA polymerase do + when

Answer 4

Condensation reaction
When it catalyses reaction between adjacent nucleotides

Question 5

Where does the energy for the DNA polymerase condensation reaction come from

Answer 5

When the two extra phosphate groups leave

Question 6

What is semi-conservative replication

Answer 6

When there are two copies of a double stranded DNA molecule but each molecule contains one strand from the original DNA molecule and one strand which is brand new.

Question 7

What is semi-conservative replication

Answer 7

When 2 new strands of DNA are formed
1 strands contains all the originals DNA
And the 2nd contains none of the original DNA

Question 8

What is the role of DNA polymerase in DNA replication

Answer 8

Joins nucleotides

Question 9

Why does DNA polymerase work in opposite directions

Answer 9

1 strands anti parallel
The shape of the nucleotides is different
Enzyme/ DNA polymerase have active site with specific shape
Only binds with the 3’ end