Formative Practice 8.3 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
What is the value of the partial pressure of oxygen in the atmospheric pressure?

The partial pressure of oxygen is 160 mm Hg.

Question 2:
In what form is carbon dioxide transported in human blood circulatory system?

Carbon dioxide is transported in the form of bicarbonate ion, carbonic acid and carbaminohaemoglobin.

Question 3:
Explain how carbon dioxide is transported from the lung capillaries to the alveolus.

• When bicarbonate ions (HCO3) in the blood plasma reach the lung capillaries, they diffuse again into the erythrocytes.

• The bicarbonate ions combine with hydrogen ions (H+) to form carbonic acid (H2CO3).

• Carbonic acid (H2CO3) then dissociates into carbon dioxide and water.

• Carbon dioxide diffuses out from the lung capillaries into the alveoli, and is expelled during exhalation.

Question 4:
In what form is oxygen carried to the tissues?

Oxygen is transported in the form of oxyhaemoglobin.

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