alleryStart learning →What happens to haemoglobin after the first oxygen molecule binds?
AIt stiffens so further binding becomes harder
BIt changes shape so the next binds more readily
CIt releases its remaining iron atoms into plasma
DIt binds carbon dioxide at the same heme site
Answer & Solution
Correct answer: B. It changes shape so the next binds more readily
1. Binding the first oxygen molecule causes a conformational change in haemoglobin.
2. That change lets the second oxygen molecule bind more readily, and each further binding eases the next.
3. The same works in reverse: once the first oxygen is dropped off, the next dissociates more readily.
4. The first option describes the opposite behaviour, which would flatten the loading curve rather than steepen it.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 22 "The Respiratory System", section 22.5 Transport of Gases_
Keep practising The Respiratory System
Browse all The Respiratory System questions for NEET PG, or explore more Physiology topics.
Related questions
Why is survival low for a baby born before 26 weeks?By how much has surfactant therapy reduced death from respiratory distress syndrome?What proportions of preterm infants are quoted as developing respiratory distress syndromeWhat happens to the fluid left in the lungs after delivery?How soon after birth does the first inhalation occur?What does the fetus move in and out during fetal breathing movements?Around which week do fetal breathing movements begin?When does a full complement of functional alveoli appear?