What is the function of folic acid in the body?

• A. Calcium absorption
• B. Blood pressure regulation
• C. Antioxidant activity
• D. Coenzyme and neural tube formation

Answer: (D)

Folic acid acts as a coenzyme in one-carbon transfer reactions that are essential for making DNA and RNA and for proper amino acid metabolism. This coenzyme role, in the form of tetrahydrofolate, provides single-carbon units needed to synthesize thymidine and purines, which are the building blocks of DNA. Because fetal neural tissue is rapidly dividing early in pregnancy, adequate folate is crucial for neural tube formation and closure, helping to prevent neural tube defects.

This function is why this vitamin is specifically tied to development and nucleotide synthesis. It isn’t primarily involved in calcium absorption (that’s vitamin D), blood pressure regulation, or antioxidant activity, so those roles don’t best describe folic acid’s main action in the body.