Question

Majority of CO₂ is carried in the form of

• A. Bicarbonates
• B. Carboxyhemoglobin
• C. Plasma
• D. None of these

Answer 1

The correct option is A

Bicarbonates

The correct option is (A).

Explanation for the correct option:

1. The transport of carbon dioxide from the cells in the body to the lungs occurs majorly through bicarbonates present in the blood plasma.
2. They are transported to the lungs and are converted to carbon dioxide for release by expiration.
3. About 70-90 % of carbon dioxide is transported in the form of bicarbonate ions.

Explanation for the incorrect options:

Option (B):

1. Carbon dioxide binds reversibly to the hemoglobin present in the RBCs and forms carboxyhemoglobin, which transports it to the lungs.
2. About 10 % of carbon dioxide is transported through carboxyhemoglobin.

Option (C):

1. Plasma is defined as the part of the blood which has no blood cells but consists of blood proteins.
2. Approximately 10% of carbon dioxide is transported to the lungs dissolved in the plasma.

Final answer: The majority of CO₂ is carried in the form of bicarbonates.