Vitamin K is required for

Options

A. formation of thromboplastin
B. conversion of fibrinogen to fibrin
C. conersion of prothrombin to thrombin
D. synthesis of prothrombin

Answer

**Step-by-step Solution:**

1. **Understanding Vitamin K's Role**: Vitamin K is essential for various physiological processes in the body, particularly in blood coagulation (clotting).

2. **Evaluating the Options**:
- **Option 1: Formation of thromboplastin**: This is incorrect. Thromboplastin is not formed by vitamin K; it is produced by platelets.
- **Option 2: Conversion of fibrinogen to fibrin**: This is also incorrect. The conversion of fibrinogen to fibrin is facilitated by the enzyme thrombin, not vitamin K.
- **Option 3: Conversion of prothrombin to thrombin**: This is incorrect as well. The conversion of prothrombin to thrombin is primarily carried out by the enzyme thrombokinase, not vitamin K.
- **Option 4: Synthesis of prothrombin**: This is correct. Vitamin K is crucial for the synthesis of prothrombin, which is a clotting factor present in blood plasma.

3. **Conclusion**: The correct answer is that vitamin K is required for the synthesis of prothrombin.

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