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7.1 Amino Acid Catabolism β Test 1
Q1. Which statement about the carbon skeletons of amino acids is correct?β Some amino acids are both glucogenic and ketogenic
Q2. Identify the correct statements about the fate of amino-acid carbon skeletons: i) Glucogenic AAs give glucose; ii) Ketogenic AAs give acetyl-CoA; iii) Ketogenic AAs are converted to mevalonate; iv) Some AAs are both glucogenic and ketogenic.β i, ii & iv
Q3. Which statements about the carbon skeletons of amino acids are correct?β Ketogenic AAs give rise to acetyl-CoA; glucogenic AAs give glucose in starvation; some AAs are both
Q4. The coenzyme of aminotransferases (transaminases) is:β Pyridoxal phosphate
Q5. Ammonia is incorporated into biomolecules through which amino acids?β Glutamate and glutamine
Q6. Amino acid metabolism involves all the following EXCEPT:β Ξ²-oxidation
Q7. Match the enzyme with its substrate:β 1-ii, 2-i, 3-iv, 4-iii
Q8. Which amino acid furnishes carbon atoms for the synthesis of both glucose and ketone bodies?β Phenylalanine
Q9. The enzyme involved in the release of NHββΊ from glutamate is:β Glutamate dehydrogenase
Q10. Glutamate undergoes oxidative deamination by the enzyme:β Glutamate dehydrogenase
Q11. Which enzyme is involved in ammonia detoxification?β Glutamate dehydrogenase
Q12. Identify the enzyme: Ξ±-ketoglutarate + NADH + NHββΊ + HβΊ β glutamate + NADβΊ + HβO.β Glutamate dehydrogenase
Q13. Transamination of which amino acid directly gives a TCA-cycle intermediate?β Glutamate
Q14. The major pathway of ammonia detoxification is:β 2-oxoglutarate β glutamate β glutamine
Q15. Which amino acid is synthesized from ribose-5-phosphate (PRPP)?β Histidine
Q16. Which amino acids are purely ketogenic?β Leucine and lysine
Q17. The following amino acids are BOTH ketogenic and glucogenic:β Tyrosine and tryptophan
Q18. Which amino acid is NOT converted to acetyl-CoA upon metabolism?β Valine
Q19. During amino acid metabolism, amino groups are excreted in mammals in the form of:β Urea
7.1 Amino Acid Catabolism β Test 2
Q20. The compound which CANNOT be metabolized to pyruvate is:β Phenylalanine
Q21. The cofactor that participates in the conversion of phenylalanine to tyrosine in phenylketonuria is:β Tetrahydrobiopterin (BH4)
Q22. The cofactor that participates in the conversion of phenylalanine to tyrosine in phenylketonuria is (variant):β Tetrahydrobiopterin (BH4)
Q23. Deficiency of phenylalanine hydroxylase causes PKU. This enzyme converts phenylalanine to:β Tyrosine
Q24. A normal adult is placed on a diet deficient only in phenylalanine. Which statement is correct?β Tyrosine becomes an essential amino acid
Q25. The coenzyme that participates in the transamination reaction is:β Pyridoxal phosphate
Q26. An intermediate of the TCA cycle that undergoes reductive amination (with ammonia) to form an amino acid is:β Ξ±-ketoglutarate
Q27. An intermediate of the TCA cycle that undergoes reductive amination to form glutamate is (variant):β Ξ±-ketoglutarate
Q28. When proteins are hydrolyzed to amino acids and then deaminated, the carbon skeleton is fed into:β Tricarboxylic acid cycle
Q29. The transamination of glutamic acid and oxaloacetate yields:β Ξ±-ketoglutarate and aspartic acid
Q30. The reactions leading to the formation of amino acids from TCA-cycle intermediates are:β Transamination
Q31. After a high-protein meal, most amino-acid nitrogen destined for urea synthesis is transferred via transamination to:β Ξ±-ketoglutarate
Q32. The common acceptor for the amino group in transamination reactions is:β Ξ±-ketoglutarate
Q33. Which coenzyme is involved in the transamination reaction of amino-acid metabolism?β Pyridoxal phosphate
Q34. The common acceptor for the amino group in transamination reactions is (variant):β Ξ±-ketoglutarate
Q35. The catalytic Ξ²-subunit of the central core of the 20S proteasome is targeted by:β Lactacystin
Q36. Which compound serves as an amino-group acceptor in amino acid catabolism?β Ξ±-ketoglutarate
Q37. In the urea cycle, why are the enzymes split between mitochondria and cytosol?β To prevent reductive amination of Ξ±-ketoglutarate in the mitochondria