Topics:
Animal Nutrition, Animal Refresher
Conditions for Kreb’s Cycle
Kreb's cycle takes place in mitochondria under:
- Aerobic condition only — Correct Answer
- Anaerobic condition only
- Both a & b
- None
Explanation:
Correct Answer: Aerobic condition only
The Krebs Cycle (Citric Acid Cycle / TCA cycle) occurs in the mitochondrial matrix and requires oxygen — it is strictly an aerobic process. Without oxygen, NADH and FADH₂ produced cannot be reoxidized by the electron transport chain, so the cycle cannot continue.
Kreb's Cycle vs Glycolysis — Comparison
| Feature | Glycolysis | Kreb's Cycle |
|---|---|---|
| Location | Cytoplasm | Mitochondrial matrix |
| Oxygen requirement | Not required (runs anaerobically too) | Required (strictly aerobic) |
| Substrate | Glucose | Acetyl CoA |
| ATP yield per turn | 2 ATP (net) | 1 GTP + 3 NADH + 1 FADH₂ per turn |
Why Kreb's Cycle is Aerobic Only
- NADH and FADH₂ generated by the cycle must be reoxidized by the Electron Transport Chain (ETC).
- ETC uses O₂ as the final electron acceptor → produces H₂O.
- Without O₂, NADH accumulates → Krebs cycle intermediates back up → cycle stops.
Why Other Options Are Wrong
- Anaerobic only → incorrect; the TCA cycle cannot function without oxygen.
- Both aerobic and anaerobic → incorrect; only glycolysis can function anaerobically.
- None → aerobic only is the correct answer.
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
