Question

Blood doesn't clot in the absence of vitamin K because it is

• A. An essential component of the clot
• B. An essential component of the platelets
• C. Essential for synthesis of prothrombin
• D. Essential for synthesis of fibrinogen

Answer 1

Answer: (C)

Essential for synthesis of prothrombin

Blood clotting factors are needed for blood to clot (coagulation). Prothrombin, or factor II, is one of the clotting factors made by the liver. Vitamin K is needed to make prothrombin and other clotting factors. So, blood does not clot in the absence of Vitamin K because it is essential for the synthesis of prothrombin and not because it is an essential component of the clot, platelets or essential for fibrinogen.

Thus, the correct answer is option C.