alleryStart learning →How many oxygen molecules can one haemoglobin molecule carry?
AUp to four
BUp to two
CUp to six
DUp to one
Answer & Solution
Correct answer: A. Up to four
1. Haemoglobin is built from four subunits arranged in a ring.
2. Each subunit carries an iron atom bound to heme at its centre.
3. Each heme binds one oxygen molecule, so one haemoglobin carries up to four.
4. That is why full occupancy of all four sites is what defines saturation.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 22 "The Respiratory System", section 22.5 Transport of Gases_
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