DNA

Question 1

What is the difference between purine and pyrimidine?

Answer 1

Purine refers to there being 2 nitrogenous bases compared to pyrimidine having one nitrogenous base.

Question 2

What are the three components of a nucleotide?

Answer 2

It has a phosphate group, a pentose sugar, and a nitrogenous base.

Question 3

What is the pentose sugar in DNA?

Answer 3

Deoxyribose

Question 4

What is the pentose sugar in RNA?

Answer 4

Ribose

Question 5

Name the bases that have a purine ring?

2

Answer 5

Adenine & Gaunine

Question 6

Name the bases that have a Pyrimidine ring?

Answer 6

Cytosine, Uracil and Thymine

Question 7

What does ATP stand for?

Answer 7

Adenosine Triphophate

Question 8

What is ATP composed of?

Answer 8

Base - Adenine
Sugar - Ribose
Three phosphate groups

Question 9

What enzyme hydrolyses ATP?

Answer 9

ATPase

Question 10

What happens when ATP is hydrolysed?

Answer 10

An inorganic ion and ADP form

Question 11

How many kilojouls do 1 mole of ATP release?

Answer 11

30.6KJ

Question 12

What reaction is it called when energy is released e.g when ATP is hydrolysed?

Answer 12

An exergonic reaction

Question 13

How is the reaction reversable?

Answer 13

Because ADP can combine with an inorganic phosphate ion to form ATP and water

Question 14

What is it called when a phosphate is added to ADP?

Answer 14

Phosphorylation

Question 15

When ADP and an inorganic phosphate ion combine, there needs to be an input of energy. What is the reaction called?

Answer 15

Endergonic

Question 16

Why is it important that energy e.g from glucose is released gradually?

Answer 16

Because too much heat can be released and wasted as heat, destroying cells

Question 17

Name five important roles of ATP?

Answer 17

• Nerve Transmisson
• Required for metabolic processes
• Active transport (change shape of carrier proteins)
• Secretion
• Movement (muscle contraction)

Question 18

How is DNA composed?

Answer 18

Two polynucleotide strands, wound around eachother in a double helix

Question 19

What are the complementary base pairings?

Answer 19

Adenine with Thymine (2 Hydrogen Bonds)

Cytosine with Guanine (3 Hydrogen Bonds)

Question 20

Why is DNA antiparallel?

Answer 20

Because one strand is arranged in the opposite direction of the other

Question 21

Why is DNA such a good molecule?

4

Answer 21

• The genetic information is protected by the “backbone”
• The genetic information is stable and goes unchanged from generation to generation
• A large molecule that can hold a lot of information
• The stands are able to separate due to the hydrogen bonds