Question

Which vitamin is essential for the synthesis of blood clotting factors?

• A. Vitamin A
• B. Vitamin C
• C. Vitamin D
• D. Vitamin K

Hint:

Important clotting factors dependent on Vitamin K:

• Factor II (Prothrombin)
• Factor VII
• Factor IX
• Factor X

Mnemonic: \textbf{“1972”} → Factors \textbf{10, 9, 7, 2} depend on Vitamin K.

Answer 1

The Correct Option is D

Concept: Vitamin K is a fat-soluble vitamin that plays a crucial role in the synthesis of blood clotting factors. It is essential for the proper functioning of the coagulation system in the human body. Vitamin K is required in the liver for the synthesis of several clotting factors, including:

• Factor II (Prothrombin)
• Factor VII
• Factor IX
• Factor X

These clotting factors help in the formation of blood clots and prevent excessive bleeding when a blood vessel is injured.
Step 1: Understanding the role of Vitamin K in coagulation.
Vitamin K acts as a cofactor for the enzyme responsible for the carboxylation of glutamic acid residues in clotting factors. This modification allows the clotting factors to bind calcium ions, which is essential for the blood clotting process. Without Vitamin K, these clotting proteins remain inactive, leading to impaired blood coagulation.
Step 2: Effects of Vitamin K deficiency.
Deficiency of Vitamin K can result in:

• Prolonged bleeding time
• Hemorrhage
• Delayed blood clotting

Newborn infants are particularly at risk of Vitamin K deficiency, which is why Vitamin K injections are often given after birth to prevent hemorrhagic disease of the newborn.
Step 3: Evaluating the options.

• Vitamin A: Important for vision and immune function.
• Vitamin C: Essential for collagen synthesis and wound healing.
• Vitamin D: Regulates calcium and phosphorus metabolism.
• Vitamin K: Essential for synthesis of blood clotting factors. (Correct)

Thus, the vitamin required for the synthesis of blood clotting factors is: \[ \text{Vitamin K} \]