IB Biology Topic B3.1.13 Oxygen Dissociation Curves Revision Notes (HL)

IB Biology Topic B3.1.13 Oxygen Dissociation Curves Revision Notes (HL) | RevisionDojo

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The Oxygen Dissociation Curve Links pO2 to Haemoglobin Saturation

An oxygen dissociation curve plots partial pressure of oxygen (pO2) on the x-axis against percentage saturation of haemoglobin on the y-axis.
It shows how haemoglobin loads and unloads oxygen across the range of lung and tissue oxygen pressures.

Reading the Curve: Loading in the Lungs, Unloading in Tissues

At high pO2 in the lungs (about 13 kPa), haemoglobin reaches roughly 100% saturation, so nearly every haem group is loaded with oxygen.
At low pO2 in respiring tissues (about 5 kPa), saturation falls sharply, so haemoglobin unloads oxygen for aerobic respiration.
The steep middle section matters most, because a small drop in pO2 causes a large release of oxygen where tissues need it.

Cooperative Binding Makes the Curve S-Shaped

The curve is sigmoid (S-shaped) rather than a straight line because of cooperative binding.
When the first oxygen molecule binds, haemoglobin changes shape and raises its affinity for the next oxygen molecules.

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The Oxygen Dissociation Curve Links pO2 to Haemoglobin Saturation

An oxygen dissociation curve plots partial pressure of oxygen (pO2) on the x-axis against percentage saturation of haemoglobin on the y-axis.
It shows how haemoglobin loads and unloads oxygen across the range of lung and tissue oxygen pressures.

Reading the Curve: Loading in the Lungs, Unloading in Tissues

At high pO2 in the lungs (about 13 kPa), haemoglobin reaches roughly 100% saturation, so nearly every haem group is loaded with oxygen.
At low pO2 in respiring tissues (about 5 kPa), saturation falls sharply, so haemoglobin unloads oxygen for aerobic respiration.
The steep middle section matters most, because a small drop in pO2 causes a large release of oxygen where tissues need it.

Cooperative Binding Makes the Curve S-Shaped

The curve is sigmoid (S-shaped) rather than a straight line because of cooperative binding.
When the first oxygen molecule binds, haemoglobin changes shape and raises its affinity for the next oxygen molecules.

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Duis aute irure dolor in reprehenderit

Note

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Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic B3.1.13: Oxygen Dissociation Curves Notes

The Oxygen Dissociation Curve Links pO2 to Haemoglobin Saturation

Reading the Curve: Loading in the Lungs, Unloading in Tissues

Cooperative Binding Makes the Curve S-Shaped

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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The Oxygen Dissociation Curve Links pO2 to Haemoglobin Saturation

Reading the Curve: Loading in the Lungs, Unloading in Tissues

Cooperative Binding Makes the Curve S-Shaped

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics