객관식
Which of the following is a reactant in cellular respiration?
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8. Respiration
Introduction to Aerobic Cellular Respiration
객관식
Which of the following is the dominant method of carbon dioxide transport in the blood during cellular respiration?
A
Bound to hemoglobin as carbaminohemoglobin
B
As carbonic acid (\(\mathrm{H_2CO_3}\)) in red blood cells
C
Dissolved directly as \(\mathrm{CO_2}\) gas in plasma
D
As bicarbonate ions (\(\mathrm{HCO_3^-}\)) dissolved in plasma
검증된 단계별 안내1
Step 1: Understand the context of the problem. Carbon dioxide (\(\mathrm{CO_2}\)) is a byproduct of cellular respiration and must be transported from tissues to the lungs for exhalation. The blood has several mechanisms to transport \(\mathrm{CO_2}\) efficiently.
Step 2: Review the methods of \(\mathrm{CO_2}\) transport in the blood. These include: (1) binding to hemoglobin as carbaminohemoglobin, (2) conversion to carbonic acid (\(\mathrm{H_2CO_3}\)) in red blood cells, (3) dissolving directly as \(\mathrm{CO_2}\) gas in plasma, and (4) conversion to bicarbonate ions (\(\mathrm{HCO_3^-}\)) dissolved in plasma.
Step 3: Focus on the dominant method of \(\mathrm{CO_2}\) transport. The majority of \(\mathrm{CO_2}\) is transported as bicarbonate ions (\(\mathrm{HCO_3^-}\)). This occurs through a chemical reaction catalyzed by the enzyme carbonic anhydrase in red blood cells: \(\mathrm{CO_2 + H_2O \rightarrow H_2CO_3 \rightarrow H^+ + HCO_3^-}\). The bicarbonate ions then diffuse into the plasma for transport.
Step 4: Compare the other methods of \(\mathrm{CO_2}\) transport. While some \(\mathrm{CO_2}\) binds to hemoglobin as carbaminohemoglobin and a small amount dissolves directly in plasma, these methods are less significant compared to the conversion to bicarbonate ions.
Step 5: Conclude that the dominant method of \(\mathrm{CO_2}\) transport in the blood during cellular respiration is as bicarbonate ions (\(\mathrm{HCO_3^-}\)) dissolved in plasma. This mechanism is efficient and plays a critical role in maintaining blood pH balance.
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