CR2 - Krebs Cycle

Question 1

What are the 4 steps of aerobic respiration?

Answer 1

1. Glycolysis (cytoplasm, anaerobic).
2. Pyruvate Oxidation (mitochondrial matrix).
3. Krebs Cycle (mitochondrial matrix).
4. Electron Transport Chain (ETC) (inner mitochondrial membrane).

Question 2

What happens during pyruvate oxidation?

Answer 2

1 CO₂ is removed from each pyruvate.
NAD⁺ → NADH.
CoA binds to 2-carbon molecule → Acetyl-CoA.

Question 3

Where does the Krebs Cycle occur?

Answer 3

Mitochondrial matrix.

Question 4

What is produced per Acetyl-CoA in the Krebs Cycle?

Answer 4

1 ATP, 3 NADH, 1 FADH₂, 2 CO₂.

Question 5

Why does the Krebs Cycle run twice per glucose?

Answer 5

Each glucose produces 2 Acetyl-CoA.

Question 6

What is the total ATP gain from the Krebs Cycle?

Answer 6

2 ATP per glucose.

Question 7

Where does the Electron Transport Chain (ETC) occur?

Answer 7

Inner mitochondrial membrane (cristae).

Question 8

What happens to NADH & FADH₂ in the ETC?

Answer 8

They donate high-energy electrons.

Question 9

How does the ETC generate ATP?

Answer 9

Electrons move through the chain, pumping H⁺ into intermembrane space, creating a concentration gradient.

Question 10

What is chemiosmosis?

Answer 10

H⁺ diffuses back into matrix through ATP synthase, producing ATP.

Question 11

What is oxidative phosphorylation?

Answer 11

The process of ATP production in the ETC using oxygen.

Question 12

What is the final electron acceptor in the ETC?

Answer 12

O₂ → Combines with H⁺ & e⁻ to form H₂O.

Question 13

How much ATP does NADH and FADH₂ produce?

Answer 13

NADH → 3 ATP
FADH₂ → 2 ATP.

Question 14

How much ATP does aerobic respiration generate in total?

Answer 14

36-38 ATP per glucose.

Question 15

How does cyanide affect the ETC?

Answer 15

Prevents O₂ from accepting electrons, stopping ATP production.