BRAINCAKEHaemoglobin
Haemoglobin (Hb) is the protein in red blood cells that carries oxygen. It is a globular, conjugated protein with a quaternary structure.
Each haemoglobin molecule is made of four polypeptide chains: two α-globin chains and two β-globin chains. Each chain is folded into a compact shape and is attached to a haem group, which is a non-protein prosthetic group. Each haem group contains an iron ion (Fe2+).
Each Fe2+ ion can combine reversibly with one oxygen molecule (O2), so one haemoglobin molecule can carry four oxygen molecules (eight oxygen atoms). Haemoglobin combined with oxygen is called oxyhaemoglobin:
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Key terms in this lesson
- conjugated protein
- A protein combined with a non-protein prosthetic group that is necessary for its function.
More in Transport in Animals
- Basic Rhythm of the Heart
- Electrocardiograms
- Aortic Aneurysms
- Red Blood Cells
- Oxygen Loading and Unloading
- The Oxygen Dissociation Curve
- Partial Pressure of Oxygen
- The Bohr Effect
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