IB Biology HL B3.1.11 Hl Haemoglobin Adaptations Questions

Explore how haem groups and cooperative binding shape oxygen loading and unloading, and how higher foetal haemoglobin affinity enables placental oxygen 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 how cooperative oxygen binding raises affinity at high pO₂ and lowers it for release at low pO₂.
Compare foetal and adult oxygen dissociation curves to explain higher affinity and placental transfer.

[Maximum number: 2]

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.

[ 1 ]

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

Question (a)

Question (b)