3.1.5.2 DNA Replication

Question 1

In the first stage of DNA replication the enzyme…causes the DNA double helix to … into 2 separate strands by breaking the … bonds between the … base pairs

Answer 1

DNA helicase
Unwind
Hydrogen
Complementary

Question 2

In the process of DNA replication once the 2 strands have separated each exposed strand acts as a…for DNA replication to occur. Activated free…in the nucleoplasm are attracted to and…bond specifically to their complementary bases on the exposed template strands by….base pairing

Answer 2

Template
Nucleotides
Hydrogen
Complementary

Question 3

In the 3rd stage of the DNA replication process once the newly added nucleotides have lined up they are joined together by the enzyme…which catalyses the formation of …bonds forming a newly synthesised …chain

Answer 3

DNA protease
Phosphodiester
Polynucleotide

Question 4

In the final stage of the DNA replication process 2…DNA molecules are produced each of which contains one of the original DNA strands and one newly…DNA strand.

Answer 4

Identical
Synthesised

Question 5

At the end of DNA replication… identical DNA molecules are produced

Answer 5

2

Question 6

DNA replication involves 2 enzymes: DNA…and DNA …

Answer 6

Helicase (causes DNA double helix to unwind and separate into 2 strands by breaking the hydrogen bonds between the complementary base pairs)

Polymerase (Once the nucleotides have lined up it catalyses the formation of Phosphodiester bonds to form a newly synthesised polynucleotide chain)

Question 7

The…replication of DNA ensures genetic continuity between generations of cells

Answer 7

Semi-conservative

Question 8

The semi conservative replication of DNA ensures…

Answer 8

Genetic continuity between generations of cells
(As one original DNA strand is always retained whilst the other strand in the molecule is newly synthesised)

Question 9

In a DNA strand, the …’ end is the end where the deoxyribose is attached to the hydroxyl group and the…‘end is the end where the deoxyribose is attached to the phosphate group

Answer 9

3’= hydroxyl group (the flatter bit of the pentagon is on the end)
5’= phosphate group (the pointed bit of the pentagon is on the end)

Question 10

DNA replication occurs in the …’ to…’ direction

Answer 10

5’ to 3’
(It first adds the nucleotides to the 3’ end so adds them going away from the 5’ which is why it’s a 5’ to 3’ direction)