2) Nucleic Acids

Question 1

What are the 3 parts of a DNA and an RNA molecule?

Answer 1

• Phosphate group
• Pentose Sugar
• Base

Question 2

What is the pentose sugar in DNA?

Answer 2

Deoxyribose

Question 3

What are always the same in each DNA and RNA molecule?

Answer 3

The phosphate group and pentose sugar

Question 4

How many carbon atoms are in a deoxyribose?

Answer 4

5

Question 5

What are the 4 bases in DNA?

Answer 5

• adenine
• thymine
• cytosine
• guanine

Question 6

What are the 2 purines?

Answer 6

Guanine and Adenine

Question 7

What are the 2 pyramidines?

Answer 7

Cytosine and Thymine

Question 8

What bonds pair the bases?

Answer 8

Hydrogen

Question 9

How many hydrogen bonds between adenine and thymine?

Answer 9

2

Question 10

How many hydrogen bonds between cytosine and guanine?

Answer 10

3

Question 11

What is stored by DNA?

Answer 11

Genetic information

Question 12

What does the genetic information do?

Answer 12

Provides instructions for growth and development

Question 13

Describe the form of DNA (3 points)

Answer 13

• double stranded molecule
• 2 polynucleotides form a double helix
• polynucleotide chains are antiparallel

Question 14

What does DNA stand for?

Answer 14

Deoxyribonucleic acid

Question 15

What is the bond between the phosphate and the pentose sugar called?

Answer 15

Phosphodiester bond

Question 16

Explain the transforming principle in terms of pneumonia and mice (3 points)

Answer 16

S-strain = harmful form of bacteria
R-strain = safe form of bacteria

1) Griffith injected mice with the bacteria and had different results:
- s-strain = mice died
- r-strain = mice lived
- s-strain killed by heat = mice lived

2) He then mixed the r-strain (safe) with the heat killed s-strain (supposedly safe)
- they died
- the information from the dead s-strain had been passed to the live r-strain

3) This is because the DNA survived the heating but the bacteria didn’t, so it was able to replicate with the necessary information to become harmful again

Question 17

What does RNA stand for?

Answer 17

Ribonucleic acid

Question 18

What is the role of RNA?

Answer 18

Transfer genetic information from the DNA to the ribosomes

Question 19

What are the ribosomes?

Answer 19

The body’s ‘protein factories’

Question 20

What do ribosomes do?

Answer 20

Read RNA to make polypeptides during translation

Question 21

What are 2 differences between DNA and RNA?

Answer 21

• RNA is made from a single polynucleotide chain

- RNA is much shorter than DNA

Question 22

What is the pentose sugar in RNA?

Answer 22

Ribose

Question 23

What are the 4 bases in RNA?

Answer 23

• adenine
• urasil
• thymine
• guanine

Question 24

What base is replaced by urasil in RNA?

Answer 24

Thymine

Question 25

What is the process of semi-conservative replication?

Answer 25

1) DNA helicase breks hydrogen bondss and unwinds DNA strands 2) Free floating nucleotides pair with complementary bases - A+T - C+G 3) Condensation reactions join the nucleotides of the new strands together to form hydrogen bonds between the base pairs - this reaction is catalysed by DNA polymerase 4) Each new molecule contains one new and one old strand

Question 26

What is the proof of semi conservative replication?

Answer 26

1) Two bacteria samples grown then spun in centrifuge - light nitrogen (DNA) settled at top - heavy nitrogen (DNA) settled at bottom 2) Sample of heavy bacteria grown with the light nitrogen was left to replicate once and then spun on centrifuge - if it was conservative, they would settle at separate ends 3) DNA settled in the middle, showing the DNA molecule contained a mixture of both nitrogens - bacterial DNA replicated semi-conservatively in the light nitrogen

Question 27

What are the 5 parts of an ATP molecule?

Answer 27

- adenine base - ribose sugar - 3 phosphate groups

Question 28

What is adenine+ribose called?

Answer 28

Adenosine

Question 29

When can ADP+inorganic phosphate be formed?

Answer 29

When ATP is hydrolysed

Question 30

What catalysis the hydrolysis of ATP?

Answer 30

The enzyme ATP hydrolase

Question 31

Where is ATP made?

Answer 31

In the mitochondria

Question 32

Why does ATP have to be constantly made?

Answer 32

- cannot be stored in the cell | - immediate source of energy

Question 33

Why is ATP better than glucose? (5 points)

Answer 33

- small amounts are ideal for body reactions - single reaction produces energy instantly - small amounts of energy are released - can be quickly regenerated from ADP (condensation) - the doses of energy are more manageable

Question 34

What are the 2 types of phosphorylation?

Answer 34

- substrate level | - oxidative

Question 35

What is phosphorylation?

Answer 35

Adding an inorganic phosphate to ADP during respiration to form ATP

Question 36

What is substrate level phosphorylation?

Answer 36

The direct transfer of a phosphate group from a donor molecule to ADP

Question 37

What is oxidative phosphorylation?

Answer 37

Production of sufficient energy to form ATP from ADP and phosphate

Question 38

How many reactions occur in oxidative phosphorylation?

Answer 38

A series of oxidation reactions

Question 39

How many reactions occur in substrate level phosphorylation?

Answer 39

1 single reaction

Question 40

In what part of respiration does oxidative phosphorylation occur?

Answer 40

Electron Transport Chain

Question 41

In what part of respiration does substrate level phosphorylation occur?

Answer 41

Glycolysis and Krebs cycle

Question 42

What are the 5 main uses of ATP?

Answer 42

- active transport - secretion - metabolic processes - movement - molecule activation

Question 43

How is ATP used in movement?

Answer 43

Muscle ontraction

Question 44

How is ATP used in metabolic processes?

Answer 44

Provides energy to make larger maromolecules

Question 45

How is ATP used in secretion?

Answer 45

To make lysozymes

Question 46

How is ATP used in molecule activation?

Answer 46

- inorganic phosphates can phosphorylate other molecules | - lowers the activation energy and makes them more reactive

Question 47

What catalyses the condensation of ADP and an inorganic phosphate to form ATP?

Answer 47

Enzyme ATP synthase