বহুনির্বাচনি (MCQ)
১. Methotrexate acts mainly by inhibiting:
ক) Thymidylate synthase directly
খ) Dihydrofolate reductase
গ) DNA polymerase
ঘ) Topoisomerase II
ঙ) Ribonucleotide reductase
উত্তর দেখুন
সঠিক উত্তর: খ) Dihydrofolate reductase
ব্যাখ্যা: Methotrexate inhibits dihydrofolate reductase, reducing tetrahydrofolate for purine and thymidine synthesis. Leucovorin (folinic acid) rescue bypasses the block.
📖 রেফারেন্স: Katzung, Basic & Clinical Pharmacology · Cancer chemotherapy: antimetabolites
