Week 1

Question 1

What happens to fat when we lose weight?

Answer 1

CO₂ + H₂O.

Question 2

What is catabolism?

Answer 2

Breakdown of molecules to release energy and extract H/e⁻.

Question 3

What is anabolism?

Answer 3

Synthesis of larger molecules using ATP or NADPH/NADH.

Question 4

What do enzymes do in metabolism?

Answer 4

Lower activation energy and speed up reactions.

Question 5

What is ATP used for?

Answer 5

Chemical, transport, and mechanical work.

Question 6

What is the energy charge?

Answer 6

A measure of cellular energy status based on ATP/ADP/AMP.

Question 7

Why is AMP important?

Answer 7

It rises sharply when ATP falls → strong signal of low energy.

Question 8

What do kinases do?

Answer 8

Add phosphate groups using ATP.

Question 9

What do phosphatases do?

Answer 9

Remove phosphate groups.

Question 10

What do phosphorylases do?

Answer 10

Use phosphate to split molecules.

Question 11

What do synthases do?

Answer 11

Condensation reactions without ATP.

Question 12

What do synthetases do?

Answer 12

Condensation reactions requiring ATP.

Question 13

What do dehydrogenases do?

Answer 13

Catalyse redox reactions using NAD⁺ or FAD.

Question 14

What does NAD⁺ do?

Answer 14

Oxidises alcohol groups → becomes NADH.

Question 15

What does FAD do?

Answer 15

Oxidises alkane → alkene → becomes FADH₂.

Question 16

Why are NAD⁺ and FAD limited?

Answer 16

They must be regenerated in the ETC.

Question 17

What is the role of CoA?

Answer 17

Carries acyl groups and traps metabolites inside the cell.

Question 18

What are the three stages of fuel oxidation?

Answer 18

Remove H/e⁻ → oxidise acetyl‑CoA → ETC + ATP synthesis.

Question 19

Why can’t cells burn fuel without doing work?

Answer 19

No ADP use → no proton flow → ETC stops → NADH/FADH₂ can’t unload.

Question 20

Why are fatty acids energy‑dense?

Answer 20

Highly reduced carbons.

Question 21

Why can’t the brain use fatty acids?

Answer 21

They cannot cross the blood–brain barrier.

Question 22

What is the main fuel for the brain?

Answer 22

Glucose.

Question 23

What is β‑oxidation?

Answer 23

Sequential removal of 2‑carbon units as acetyl‑CoA.

Question 24

What does glycolysis produce?

Answer 24

2 ATP, 2 NADH, 2 pyruvate.

Question 25

What does the Krebs cycle produce per acetyl‑CoA?

Answer 25

3 NADH, 1 FADH₂, 1 GTP.

Question 26

What increases immediately when exercise begins?

Answer 26

ATP consumption.

Question 27

What happens when ADP rises?

Answer 27

ATP synthase speeds up → ETC speeds up → fuel oxidation increases.

Question 28

Which muscle fibres are slow‑twitch?

Answer 28

Type I.

Question 29

Which muscle fibres are fast‑twitch?

Answer 29

Type IIb.

Question 30

Which fibres have many mitochondria?

Answer 30

Type I.

Question 31

Which fibres rely on glycolysis?

Answer 31

Type IIb.

Question 32

What fuel is used first in gentle exercise?

Answer 32

Glucose.

Question 33

What hormone changes occur in gentle exercise?

Answer 33

↓ insulin, ↑ glucagon.

Question 34

What does glucagon stimulate?

Answer 34

Liver glycogen breakdown and adipose lipolysis.

Question 35

Why does lactate not accumulate in gentle exercise?

Answer 35

Liver converts it back to glucose (Cori cycle).

Question 36

What limits fatty acid oxidation in moderate exercise?

Answer 36

β‑oxidation enzymes reach Vmax.

Question 37

What fuel increases when FA oxidation maxes out?

Answer 37

Glucose oxidation.

Question 38

What is the main fuel in strenuous exercise?

Answer 38

Muscle glycogen.

Question 39

Why is muscle glycogen essential for high intensity?

Answer 39

Blood glucose supply is too slow.

Question 40

Why does lactate rise in very strenuous exercise?

Answer 40

Glycolysis exceeds mitochondrial capacity → NAD⁺ must be regenerated.

Question 41

Why is glycolysis used in sprinting?

Answer 41

Fast ATP production; Type IIb fibres have few mitochondria.

Question 42

What is creatine phosphate used for?

Answer 42

Immediate ATP buffer for first ~5 seconds.

Question 43

What causes “hitting the wall”?

Answer 43

Glycogen depletion → only fatty acids left → low power output.

Question 44

What activates fatty acids for oxidation?

Answer 44

Conversion to fatty acyl‑CoA.

Question 45

How many ATP equivalents does FA activation cost?

Answer 45

2 ATP (ATP → AMP).

Question 46

What transports FA into mitochondria?

Answer 46

Carnitine shuttle (CAT‑1 and CAT‑2).

Question 47

What does CAT‑1 do?

Answer 47

Converts FA‑CoA → FA‑carnitine.

Question 48

What does CAT‑2 do?

Answer 48

Converts FA‑carnitine → FA‑CoA.

Question 49

What are the four steps of β‑oxidation?

Answer 49

FAD oxidation → hydration → NAD⁺ oxidation → thiolysis.

Question 50

What does each β‑oxidation cycle produce?

Answer 50

1 acetyl‑CoA, 1 NADH, 1 FADH₂.

Question 51

How many acetyl‑CoA from palmitate (C16)?

Answer 51

8.

Question 52

How many β‑oxidation cycles for palmitate?

Answer 52

7.

Question 53

What traps glucose inside the cell?

Answer 53

Hexokinase (glucose → G6P).

Question 54

What is the rate‑limiting enzyme of glycolysis?

Answer 54

PFK‑1.

Question 55

What is the net ATP yield of glycolysis?

Answer 55

2 ATP.

Question 56

What are the fates of pyruvate?

Answer 56

Acetyl‑CoA (aerobic) or lactate (anaerobic).

Question 57

What does PDH produce?

Answer 57

Acetyl‑CoA + NADH.

Question 58

Where does the Krebs cycle occur?

Answer 58

Mitochondrial matrix.

Question 59

What is the carrier molecule of the Krebs cycle?

Answer 59

Oxaloacetate.

Question 60

What are the products of one Krebs cycle turn?

Answer 60

3 NADH, 1 FADH₂, 1 GTP, 2 CO₂.

Question 61

What regulates the Krebs cycle?

Answer 61

Stimulated by ADP/NAD⁺; inhibited by ATP/NADH.

Question 62

What is the main purpose of the Krebs cycle?

Answer 62

Generate NADH and FADH₂ for the ETC.