Topics:
Animal Nutrition, Animal Refresher
Energy Yield of ATP Hydrolysis
1 mole of ATP on hydrolysis yields ______ energy.
- 7.3 kcal — Correct Answer
- 14.8 kcal
- 30.5 Kcal
- None
Explanation:
Correct Answer: 7.3 kcal
Under standard physiological conditions, the hydrolysis of one mole of ATP → ADP + Pᵢ releases 7.3 kcal (30.5 kJ) of free energy. This is the standard free energy of hydrolysis (ΔG°') used in biochemistry. Note: 7.3 kcal/mol = 30.5 kJ/mol.
Energy Currency of the Cell — ATP
| Reaction | Energy Release |
|---|---|
| ATP → ADP + Pᵢ | 7.3 kcal/mol (30.5 kJ/mol) |
| ADP → AMP + Pᵢ | 7.3 kcal/mol |
| Phosphocreatine → Creatine + Pᵢ | 10.3 kcal/mol (higher energy) |
| Glucose (aerobic oxidation) | 38 ATP produced |
| 1 kg TDN | 4.4 Mcal digestible energy |
ATP Production from Different Substrates
- 1 mol Glucose (aerobic) → 38 ATP
- 1 mol Glucose (anaerobic) → 2 ATP
- 1 mol Palmitic acid → 129 ATP (highest per mole)
- 1 mol Acetate (VFA) → 10 ATP
- 1 mol Propionate (VFA) → 17 ATP
- 1 mol Butyrate (VFA) → 25 ATP
Why Other Options Are Wrong
- 14.8 kcal → approximately double the correct value; no biochemical basis.
- 30.5 kcal → confusion with kJ value (30.5 kJ = 7.3 kcal); units are mixed up.
- None → 7.3 kcal/mol is the standard free energy of ATP hydrolysis.
📚 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.
