本题目来源于试卷: Form and Function B.6 Gas Exchange，类别为 IB生物学
[单选题]
Ventilation is importafn dq6 2sjm+a,p ./3wevqemz+ nt in mainoyhk u*8vvp49h*xzu2ft(4ytdl) 2a itaining the concentration gradients of oxygen and carbon dioxidt d82yuufx oyvt94l * *p2ahk (v)hz4ie between the air in the alveoli and blood flowing in adjacent capillaries.
Which of the following shows the correct concentration gradients when the diffusion of gases is taking place?
A. Diffusion of oxygen into the blood is Higher oxygen concentration in alveoli;Diffusion of carbon dioxide into the alveoli is Lower carbon dioxide concentration in the alveoli
B. Diffusion of oxygen into the blood is Higher oxygen concentration in alveoli;Diffusion of carbon dioxide into the alveoli is Lower carbon dioxide concentration in the blood
C. Diffusion of oxygen into the blood is Lower oxygen concentration in the blood;Diffusion of carbon dioxide into the alveoli is Higher carbon dioxide concentration in the alveoli
D. Diffusion of oxygen into the blood is Lower oxygen concentration in the alveoli;Diffusion of carbon dioxide into the alveoli is Higher carbon dioxide concentration in the blood
参考答案: A
本题详细解析:
For oxygen to diffuse into the blood, there must be a higher concentration of oxygen in the alveoli than in the blood (Choice D). This is because gases only diffuse down their concentration gradients. Similarly, for carbon dioxide to diffuse into the alveoli, there should be a lower concentration of carbon dioxide in the alveoli (Choice C) and a higher concentration of carbon dioxide in the blood (Choice B).
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