B₁₂/Folate Problem set

Question 5: Folate in the synthesis of DNA

Correct!

Folate derivatives are required for the synthesis of which DNA nucleotides?

A.	adenylate and guanylate
B.	cytidylate and thymidylate
C.	all four nucleotides
D.	thymidylate only
E.	adenylate, guanylate, and thymidylate It is easy to see why rapidly proliferating cells such as fetuses, reticulocytes or tumors are so sensitive to folate deprivation. A folate derivative (N10-formyl-THF) is needed at an early stage for the synthesis of all purines (e.g., adenylate and guanylate), including those in RNA as well. In contrast, the only pyrimidine that requires folate for its synthesis is thymidine. More about this reaction in the next question...