23% amount of `CO_2` is transported in the blood as

Options

A. bicarbonate ions
B. carbaminohaemoglobin
C. carboxyhaemoglobin
D. carbonates

Answer

To solve the question regarding how 23% of carbon dioxide (CO₂) is transported in the blood, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding CO₂ Transport**:
- Carbon dioxide is a waste product of cellular metabolism and needs to be transported from tissues to the lungs for exhalation.

2. **Forms of CO₂ Transport**:
- CO₂ is transported in the blood in three main forms:
- Dissolved in plasma
- As bicarbonate ions (HCO₃⁻)
- Bound to hemoglobin as carbamino compounds (Carbo-Amino-Hemoglobin)

3. **Percentage Breakdown**:
- Approximately 7% of CO₂ is transported dissolved in plasma.
- About 23% of CO₂ is transported as bicarbonate ions.
- Roughly 70% of CO₂ is transported as bicarbonate ions, which is the most significant form.

4. **Identifying the Correct Answer**:
- Since the question specifically asks about the 23% of CO₂ transport, the correct answer is that this percentage is transported as bicarbonate ions (HCO₃⁻).

5. **Conclusion**:
- Therefore, the answer to the question is that 23% of CO₂ is transported in the blood as bicarbonate ions.