問題詳情

43. Folic acid is required for nucleotide synthesis. Which of the following statementsabout folic acid is incorrect?


(A) Folic acid is a cofactor in many metabolic reactions involving one-carbon(methyl-, methylene-, formyl-) functional groups.
(B) These one-carbon functional groups are usually modified at the N5 or NI0position of folic acid.
(C) Sulfonamide inhibits bacterial growth by inhibiting the formation of para-amino benzoic acid (PABA), a precursor of folic acid.
(D) Tetrahydrofolate is the activated form of folic acid. The hydrogens arenormally added to N5, C6, C7, and N8 of folic acid.
(E) The cancer chemotherapeutic drug methotrexate is similar in structure tofolic acid and can inhibit the synthesis of tetrahydrofolate.

參考答案

答案:C
難度:計算中-1
書單:沒有書單,新增

用户評論

【用戶】各選項詳解

【年級】小五下

【評論內容】葉酸主要參與單碳移轉反應,可作為甲基提供者,磺胺類藥物(Sulfonamide)可作為抗生素,主要是抑制微生物對於葉酸前驅物PABA的利用(utilization),而不是形成(formation)。