DNA replication

Question 1

Which bases are involved in DNA?

Answer 1

ACTG

Question 2

What type of structure is DNA?

Answer 2

Double helix structure

Question 3

Where are bases joined to in DNA?

Answer 3

Joined from 3’ to 5’ OH’s of the sugar by a phosphate group

Question 4

What are genes?

Answer 4

The chunks of the DNA code when it has been split

Question 5

What do genes control?

Answer 5

Much of who we are, eg, height and eye colour

Question 6

How many nucleotides are in the complete human genome?

Answer 6

3 billion

Question 7

How many genes are in the complete human genome?

Answer 7

31,000

Question 8

Which bases pair together?

Answer 8

Thymine and adenine

Cytosine and guanine

Question 9

How many hydrogens between thymine and adenine?

Answer 9

2

Question 10

How many hydrogens between cytosine and guanine?

Answer 10

3

Question 11

What is the base pairing always like?

Answer 11

Purine to pyrimidine

Question 12

Which bases are purines?

Answer 12

Adenine

Guanine

Question 13

Which bases are pyrimidine?

Answer 13

Thymine

Cytosine

Question 14

What does the base pairing mean?

Answer 14

The DNA strands are complimentary to each other

Question 15

When the double stranded DNA splits, was are the two strands formed?

Answer 15

Leading strand

Lagging strand

Question 16

Why does DNA replicate?

Answer 16

When a cell divides each cell needs a full set/copy of the DNA

Question 17

What type of replication is DNA replication? What does this mean?

Answer 17

Semi-conservative

The strands formed are half new and half old

Question 18

What was Watson and Cricks experiment?

Answer 18

They had a N15 and an N14 isotopes in bacteria

Then the first generation produced contained half of each isotope

Question 19

What does DNA helices do?

Answer 19

Unwinds the DNA strand

Question 20

What does DNA polymerase do?

Answer 20

Makes new DNA strand

Question 21

What does RNA primate do?

Answer 21

Makes RNA primers for the lagging strand

Question 22

What does RNase H do?

Answer 22

Removes RNA primers

Question 23

What does DNA ligase do?

Answer 23

Joins the Okazaki fragments to create one continuous strand

Question 24

What does DNA polymerase catalyse?

Answer 24

the step by step addition of deoxyribonucleotide units to a growing DNA chain

Question 25

Which 4 activated precursors does DNA polymerase need to work?

Answer 25

dATP
dGTP
dTTP
dCTP + Mg2+

Question 26

Where does DNA polymerase add the deoxyribonucleotides to ?

Answer 26

the 3’-hydroxyl group of a DNA chain called the primer

Question 27

What type of reaction is the one involving DNA polymerase?

Answer 27

Nucleophilic attack of the 3’OH terminus of the primer DNA on the innermost phosphorus atom of a deoxynucleoside triphosphate

Question 28

What provides the energy for the DNA polymerase chain elongation reaction?

Answer 28

The nucleophilic attack releases a diphosphate unit which Is hydrolysed by inorganic pyrophosphatase

Question 29

How often does DNA polymerase make a mistake?

Answer 29

Once every 10,000,000 base pairs

Question 30

What does PCR do?

Answer 30

Amplifies specific DNA sequences

Question 31

What are the three steps of PCR?

Answer 31

Denaturation
Annealing
Elongation

Question 32

What happens in denaturation?

Answer 32

Strand separation

Two strands of DNA are separated by heating

Question 33

What happens during annealing?

Answer 33

Hybridisation of primers

Short strands of DNA flanking the 3’ ends of both strands of DNA are hybridised to the sequences

Question 34

What happens during elongation?

Answer 34

DNA synthesis

DNA polymerase is added and elongation of both primers occurs