NEET Biology: Exchange gases Practice Questions
14 free multiple-choice questions on Exchange gases (Respiration) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. The respiratory membrane in the lungs is composed of which two main layers?
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Correct answer: B — Alveolar epithelium and capillary endothelium
The respiratory membrane consists of the thin layer of alveolar epithelium and the thin layer of capillary endothelium, which is the site of gas exchange.
Q2. Which part of the respiratory system is responsible for the mechanical process of breathing (inhalation and exhalation)?
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Correct answer: B — Diaphragm
The diaphragm is the principal muscle responsible for changing the volume of the thoracic cavity, which drives the inhalation and exhalation process.
Q3. The driving force for the diffusion of oxygen from the alveoli into the blood is the difference in:
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Correct answer: B — Pressure
Diffusion is driven by the difference in partial pressure; oxygen moves from the area of higher partial pressure (alveoli) to the area of lower partial pressure (blood).
Q4. The movement of respiratory gases (oxygen and carbon dioxide) from the alveoli into the pulmonary capillaries is primarily driven by which principle?
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Correct answer: A — Diffusion
Gas exchange across the respiratory membrane occurs via simple diffusion, which is driven by the difference in partial pressures of the gases between the alveolar air and the blood in the capillaries.
Q5. What is the primary gas that is absorbed from the atmosphere into the blood through the lungs?
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Correct answer: D — Oxygen
Oxygen (O₂) is the essential gas taken in from the atmosphere by the lungs to be transported to the body tissues.
Q6. The fundamental principle governing the exchange of gases (O2 and CO2) between the alveolar air and the blood is:
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Correct answer: D — Diffusion
Gas exchange across the alveolar membrane and capillary wall occurs solely by the process of diffusion, driven by the partial pressure gradient of the gases.
Q7. The process by which oxygen moves from the blood into the tissues relies on the difference in:
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Correct answer: B — Partial pressure of oxygen
Oxygen moves from an area of higher partial pressure to an area of lower partial pressure. In tissues, the partial pressure of O2 is higher than in the blood flowing through the capillaries, driving O2 diffusion into the cells.
Q8. Which structure is responsible for the transport of oxygen from the lungs to the rest of the body via the bloodstream?
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Correct answer: D — Blood vessels
Oxygen is transported via hemoglobin within the blood vessels.
Q9. Which statement accurately describes the relationship between ventilation and gas exchange?
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Correct answer: A — Adequate ventilation ensures that the partial pressure gradients are maintained for efficient exchange.
Effective gas exchange relies on maintaining the necessary partial pressure gradients across the respiratory surfaces. Proper ventilation ensures these gradients exist for efficient diffusion.
Q10. The movement of gases into the bloodstream is fundamentally driven by which principle?
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Correct answer: A — Diffusion
Gas exchange and transport rely on the principle of diffusion, where gases move from an area of higher partial pressure to an area of lower partial pressure.
Q11. During external respiration, the process of gas exchange occurs across which specific barrier separating the inhaled air and the blood?
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Correct answer: B — Capillary walls of the alveoli
The exchange of gases occurs across the extremely thin walls of the pulmonary capillaries and the alveolar membrane, which form the barrier for gas transfer.
Q12. What is the primary function of the respiratory pigments (like hemoglobin) in the blood during gas exchange?
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Correct answer: C — To bind and transport respiratory gases from the lungs to the body tissues
Respiratory pigments, primarily hemoglobin in red blood cells, are essential for binding oxygen in the lungs and transporting it throughout the circulatory system to the body's tissues.
Q13. Which factor is primarily responsible for the rate of diffusion of oxygen from the alveoli into the pulmonary capillaries?
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Correct answer: D — The partial pressure difference
According to Fick's law of diffusion, the rate of diffusion is directly proportional to the partial pressure difference across the membrane. A larger partial pressure difference leads to faster diffusion.
Q14. Which of the following factors primarily determines the rate of gaseous exchange across the respiratory membrane in the lungs?
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Correct answer: C — The partial pressure gradient of the gases
The rate of gas exchange is fundamentally governed by Fick's law of diffusion, which states that the rate of diffusion is proportional to the surface area and the partial pressure gradient. The partial pressure gradient (the difference in partial pressures of the gas between the alveoli and the blood) is the driving force for the exchange.
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