Both vitamin K and vitamin C are involved in
**Core Concept**
Vitamins K and C play crucial roles in various bodily functions, including bone health, blood clotting, and collagen synthesis. Both vitamins are essential for maintaining optimal health and preventing deficiencies.
**Why the Correct Answer is Right**
Vitamin K is a fat-soluble vitamin that serves as a cofactor for the enzyme gamma-glutamyl carboxylase, which is necessary for the activation of clotting factors II, VII, IX, and X in the liver. This process is essential for the blood clotting cascade. On the other hand, vitamin C, a water-soluble vitamin, is a cofactor for the enzyme prolyl hydroxylase, which is involved in the hydroxylation of proline residues in collagen. This hydroxylation is necessary for the stabilization of collagen fibers, which provide structure and elasticity to connective tissue.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while both vitamins are involved in bone health, this is not the primary function they share.
**Option B:** Incorrect because although both vitamins are essential for overall health, this is too broad and does not accurately describe their shared function.
**Option C:** Incorrect because vitamins K and C do not have a direct role in the synthesis of fatty acids.
**Clinical Pearl / High-Yield Fact**
Vitamin K deficiency can lead to bleeding disorders, while vitamin C deficiency can result in scurvy, characterized by connective tissue weakness and poor wound healing.
**Correct Answer:** D.