Topics:
Animal Physiology, Animal Refresher
Oxygen Molecules Carried per Hemoglobin Molecule
Number of oxygen molecules carried by each hemoglobin (Hb) molecule is:
- 2
- 4 — Correct Answer
- 6
- 8
Explanation:
Correct Answer: 4
Each hemoglobin molecule carries 4 molecules of oxygen — one per heme group (one per iron atom).
Hemoglobin Structure
- One Hb molecule = 4 polypeptide chains (2α + 2β) + 4 heme groups
- Each heme group = 1 iron atom (Fe²⁺) + porphyrin ring
- Each Fe²⁺ binds 1 O₂ → total 4 O₂ per Hb molecule
Cooperative Binding
Hemoglobin shows cooperative binding — binding of the first O₂ increases affinity for the next O₂ molecule, producing the characteristic sigmoidal (S-shaped) oxygen-hemoglobin dissociation curve.
Key Numbers
- 1 Hb molecule → 4 O₂
- 1 gram Hb → 1.34 ml O₂
- 15 g/dl Hb (normal) → ~20 ml O₂ per 100 ml blood
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
