IB Biology HL B3.1.11 Hl Haemoglobin Adaptations Questions

Explore how haem groups and cooperative binding support oxygen loading and unloading, and why fetal haemoglobin has higher affinity for placental transfer in IB Biology HL B3.1.11.

Exam points

Explain that four haemoglobin subunits each contain a haem group that binds oxygen reversibly.
Explain cooperative binding: binding one oxygen changes haemoglobin conformation and increases affinity for subsequent oxygen molecules, supporting loading at high pO2 and unloading at low pO2.
Compare fetal and adult haemoglobin affinity using left-shifted dissociation curves and explain placental oxygen transfer.

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Study B3.1.11 (HL)—Haemoglobin adaptations conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

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Oxygen dissociation curves show the percentage of oxygen saturation of adult haemoglobin (Hb) at different oxygen concentrations, as measured in partial pressure of oxygen ( $\mathrm{pO}_{2}$ ).

Figure for Question IB Biology HL B3.1.11 Hl Haemoglobin Adaptations Questions question 1 — IB Biology HL

(a)

On the graph, sketch an oxygen dissociation curve for foetal haemoglobin.

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curve should be the sigmoidal and drawn to the left of the oxygen dissociation curve;

Labels not necessary.

Not necessary that curves meet at high $\mathrm{pO}_{2}$ .

(b)

Describe an adaptation of haemoglobin for the transport of oxygen.

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IB Biology HL B3.1.11 Hl Haemoglobin Adaptations Questions question 1

Question (a)

Question (b)