IB DP Biology B3.1 Gas exchange -FA 2025-IB Style Questions- SL Paper 1

Question

The graph shows the concentration of the lipid lecithin in the amniotic fluid surrounding the fetus during normal gestation. This lipid is produced in the lungs of the fetus and acts as a surfactant.

What problem may occur in a baby born before 34 weeks gestation?

A. Type I pneumocytes do not produce sufficient surfactant for lungs to inflate.

B. There are no type II pneumocytes.

C. The alveolar walls stick together.

D. The alveoli are too large.

Answer/Explanation

Ans:C

Question

Pressure changes inside the thorax cause the movement of air in and out of the lung alveoli
during ventilation. Alveolar pressure correlates to thoracic pressure. The diagram shows pressure
changes in lung alveoli during ventilation in relation to normal atmospheric pressure. What causes
forced movement of air out of the lungs at T?

Answer/Explanation

Ans: B

Question

Where in the body are type I pneumocytes found?

    1. Alveoli

    2. Nephrons

    3. Capillaries

    4. Trachea

Answer/Explanation

Ans: A

Question

Which is an adaptation to increase rates of gas exchange in the lung?

    1. Small surface area

    2. Dry surface

    3. High vascularization

    4. Muscular alveoli

Answer/Explanation

Ans: C

Scroll to Top