Nucleotides

Question 1

What are the three main components of nucleotides?

Answer 1

1) nitrogenous base
2) a pentose sugar
3) 1, 2 or 3 phosphate groups

Question 2

What is the structural difference between RNA and DNA?

Answer 2

RNA has an OH group on carbon 2, whereas in DNA this is replaced with a single hydrogen (deoxy)

Question 3

Describe the structure of pyrimidines. Which bases are pyrimidines?

Answer 3

Single ring, with 4 carbon atoms and 2 nitrogen atoms. Includes cytosine, thymine and uracil

Question 4

Describe the structure of purines. Which bases are purines?

Answer 4

Double ring structure, including guanine and adenine

Question 5

Describe the general structure of ATP.

Answer 5

Adenine, ribose and triphosphate

Question 6

Which bonds lie between the phosphates in ATP?

Answer 6

Phosphoanhydride bonds

Question 7

What bond is between the first phosphate and the 5th carbon atom of ATP? How much energy does it yield?

Answer 7

Ester bond, yielding 14kJ/mol

Question 8

How much energy does each phosphoanhydride bond yield?

Answer 8

30kJ/mol

Question 9

Where does glycolysis occur?

Answer 9

In the cytosol

Question 10

How many ATP molecules are used per glucose unit in glycolysis?

Answer 10

2

Question 11

How many ATP molecules are regenerated per glucose unit in glycolysis?

Answer 11

4 (2 per pyruvate)

Question 12

How many NADH molecules are produced per glucose unit in glycolysis?

Answer 12

2

Question 13

Where does oxidative phosphorylation occur?

Answer 13

In the mitochondria (matrix)

Question 14

How many ATP molecules are produced per NADH in oxidative phosphorylation?

Answer 14

3

Question 15

How many ATP molecules are produced per FADH2 in oxidative phosphorylation?

Answer 15

2

Question 16

Where do NADH and FADH2 donate electrons to in oxidative phosphorylation?

Answer 16

The electron transport chain

Question 17

What does NAD+ stand for and where is it derived from?

Answer 17

Nicotinaminde adenine dinucleotide, derived from B3

Question 18

How many ATP molecules does NAD+ produce?

Answer 18

3

Question 19

What does FADH2 stand for and where is it derived from?

Answer 19

Flavin adenine dinucleotide is derived from B2

Question 20

How many ATP molecules does FADH2 produce?

Answer 20

2

Question 21

Give 2 routes for pyruvate molecules after glycolysis.

Answer 21

1) enters the krebs cycle, 2) is reduced to lactate via the cori cycle

Question 22

What is oxidised as pyruvate is reduced?

Answer 22

NADH

Question 23

Which enzyme is required for the pyruvate-NADH redox reaction?

Answer 23

Lactate dehydrogenase

Question 24

What is lactate production important for?

Answer 24

1) high intensity exercise 2) anoxia/hypoxia 3)erythrocytes

Question 25

What is the term for the production of gluose in the liver?

Answer 25

Gluconeogenesis

Question 26

What is GDV and why is lactate production useful in practise?

Answer 26

Gastric dilation volvulus. The stomach bloats and twists, causing anoxia in vital organs, buildup of lactate in the blood is measurable, indicating extent of damage

Question 27

What is the difference between NADP+ and NAD+?

Answer 27

NADP+ has a phosphate group on the 2'C OH group

Question 28

Give some uses of NADPH

Answer 28

1) reductive biosynthesis 2)phagocytosis-enzyme called NADPH oxidases 3) drug metabolism 4) nitric oxide synthesis

Question 29

What is reductive biosynthesis?

Answer 29

Synthesis of fatty acids and cholestrol

Question 30

How is NADPH regenerated?

Answer 30

By the oxidative phase of the pentose phosphate pathway

Question 31

Give two molecules formed with coenzyme A

Answer 31

1) acetyl coA 2) fatty acyl coA

Question 32

What is cellular respiration?

Answer 32

The process by which cells consume O2 and produce CO2

Question 33

Describe acetyl coA production from glucose.

Answer 33

Glucose converted to pyruvate in glycolysis, 2C is converted to acetyl coA

Question 34

Describe acetyl coA production from fatty acids.

Answer 34

Long chain of carbons and a carboxylic acid is metabolised by beta-oxidation, removing 2C at a time. These are converted to acetyl coA

Question 35

Describe acetyl coA production from amino acids.

Answer 35

Amino group is removed. In mammals, ammonia is converted to urea. In birds and reptiles, ammonia is converted to uric acid, in fish it is excreted directly. Remaining carbon skeleton can be converted to acetyl coA

Question 36

What happens to O2 in oxidative phosphorylation?

Answer 36

It is reduced to H2O

Question 37

What is cAMP?

Answer 37

Cyclic AMP is a second messenger produced in response to hormomes and other chemical signals

Question 38

How is cAMP formed?

Answer 38

From ATP in a reaction catalysed by adenylate cyclase (AC)