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8.3 Coenzyme Biosynthesis (NAD/FAD/CoA) — Test 1
Q1. Which vitamin is the precursor for the synthesis of coenzyme A (CoA)?✓ Pantothenic acid (B5)
Q2. The reactive functional group of coenzyme A that carries acyl groups is:✓ A thiol (–SH) group
Q3. Which vitamin is the precursor for the synthesis of FAD and FMN?✓ Riboflavin (B2)
Q4. In the de novo synthesis of NAD⁺ in humans, the key amino-acid precursor is:✓ Tryptophan
Q5. Which vitamin (when supplied directly in the diet) is used in the salvage route for NAD⁺ synthesis?✓ Niacin (B3 / nicotinic acid / nicotinamide)
Q6. NADP⁺ differs from NAD⁺ by the presence of an additional:✓ Phosphate group on the adenine ribose (2'-position)
Q7. NAD⁺ and FAD both contain which common nucleotide component?✓ AMP (adenine nucleotide)
Q8. The committed reaction that adds the second phosphate to convert NAD⁺ into NADP⁺ is catalyzed by:✓ NAD kinase
Q9. Which coenzyme is essential as the acyl-group carrier in fatty-acid oxidation and the TCA cycle?✓ Coenzyme A
Q10. The deficiency disease pellagra results from a lack of the vitamin needed to make which coenzyme?✓ NAD⁺ / NADP⁺
Q11. The flavin coenzyme FMN is synthesized from riboflavin by the addition of:✓ A phosphate group (from ATP)
Q12. Which of the following coenzymes does NOT contain an adenine nucleotide?✓ Tetrahydrofolate (THF)
Q13. PRPP (phosphoribosyl pyrophosphate) is required in NAD⁺ synthesis to:✓ Donate the ribose-phosphate to the nicotinate/quinolinate ring
Q14. Which statement about nucleotide coenzymes is correct?✓ NAD⁺ is derived from niacin/tryptophan; FAD from riboflavin; CoA from pantothenate