in which of the following forms ,CO_2 is not transported in the blood?

Options

A. carbaminohaemoglobin
B. in dissolved state through plasma
C. carboxyhaemoglobin
D. Bicarbonates

Answer

To solve the question "In which of the following forms, CO₂ is not transported in the blood?", we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding CO₂ Transport**:
- Carbon dioxide (CO₂) is transported in the blood in three main forms: as bicarbonate ions (HCO₃⁻), bound to hemoglobin as carbaminohemoglobin, and dissolved in plasma.

2. **Analyzing the Options**:
- **Option A: Carbaminohemoglobin**:
- This is a complex formed when CO₂ binds to hemoglobin. Approximately 20-25% of CO₂ is transported in this form. Thus, this option is incorrect as CO₂ is indeed transported as carbaminohemoglobin.

- **Option B: Dissolved State through Plasma**:
- About 7% of CO₂ is transported in a dissolved state in the plasma. Therefore, this option is also incorrect as CO₂ is transported in this form.

- **Option C: Carboxyhemoglobin**:
- This term refers to the complex formed when hemoglobin binds with carbon monoxide (CO), not carbon dioxide. Therefore, this option is correct as CO₂ is not transported in the form of carboxyhemoglobin.

- **Option D: Bicarbonates**:
- The majority of CO₂ (about 70%) is transported in the form of bicarbonate ions. Thus, this option is incorrect as CO₂ is indeed transported as bicarbonates.

3. **Conclusion**:
- The only form in which CO₂ is not transported in the blood is **Carboxyhemoglobin** (Option C).

### Final Answer:
**Carboxyhemoglobin** is the form in which CO₂ is not transported in the blood.

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