Chapter 18: Amino Acid Oxidation Ad The Production Of Urea

27 Questions | Total Attempts: 478

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Oxidation Number Quizzes & Trivia

Questions and Answers
  • 1. 
    Which of these is not a protease that acts in the small intestine?
    • A. 

      Chymotrypsin

    • B. 

      Elastase

    • C. 

      Enteropeptidase

    • D. 

      Secretin

    • E. 

      Trypsin

  • 2. 
    In the digestion of protein that occurs in the small intestine, which enzyme is critical in the activation of zymogens?
    • A. 

      Enteropeptidase

    • B. 

      Hexokinase

    • C. 

      Papain

    • D. 

      Pepsin

    • E. 

      Secretin

  • 3. 
    Which of the following is a zymogen that can be converted to an endopeptidase that hydrolyzes peptide bonds adjacent to Lys and Arg residues?
    • A. 

      Chymotrypsinogen

    • B. 

      Pepsin

    • C. 

      Pepsinogen

    • D. 

      Trypsin

    • E. 

      Trypsinogen

  • 4. 
    In amino acid catabolism, the first reaction for many amino acids is a(n):
    • A. 

      Decarboxylation requiring thiamine pyrophosphate (TPP).

    • B. 

      Hydroxylation requiring NADPH and O2.

    • C. 

      Oxidative deamination requiring NAD+.

    • D. 

      Reduction requiring pyridoxal phosphate (PLP).

    • E. 

      Transamination requiring pyridoxal phosphate (PLP).

  • 5. 
    The coenzyme required for all transaminations is derived from:
    • A. 

      Niacin.

    • B. 

      Pyridoxine (vitamin B6).

    • C. 

      Riboflavin.

    • D. 

      Thiamin.

    • E. 

      Vitamin B12.

  • 6. 
    The coenzyme involved in a transaminase reaction is:
    • A. 

      Biotin phosphate.

    • B. 

      Lipoic acid.

    • C. 

      Nicotinamide adenine dinucleotide phosphate (NADP+).

    • D. 

      Pyridoxal phosphate (PLP).

    • E. 

      Thiamine pyrophosphate (TPP).

  • 7. 
    Transamination from alanine to alpha-ketoglutarate requires the coenzyme:
    • A. 

      Biotin.

    • B. 

      NADH.

    • C. 

      No coenzyme is involved.

    • D. 

      Pyridoxal phosphate (PLP).

    • E. 

      Thiamine pyrophosphate (TPP).

  • 8. 
    Pyridoxal phosphate is a cofactor in this class of reactions:
    • A. 

      Acetylation.

    • B. 

      Desulfuration.

    • C. 

      Methylation.

    • D. 

      Reduction.

    • E. 

      Transamination.

  • 9. 
    Which of the following is not true of the reaction catalyzed by glutamate dehydrogenase?
    • A. 

      It is similar to transamination in that it involves the coenzyme pyridoxal phosphate (PLP).

    • B. 

      NH4+ is produced.

    • C. 

      The enzyme can use either NAD+ or NADP+ as a cofactor.

    • D. 

      The enzyme is glutamate-specific, but the reaction is involved in oxidizing other amino acids.

    • E. 

      Alpha-Ketoglutarate is produced from an amino acid.

  • 10. 
    Glutamate is metabolically converted to alpha-ketoglutarate and NH4+ by a process described as:
    • A. 

      Deamination.

    • B. 

      Hydrolysis.

    • C. 

      Oxidative deamination.

    • D. 

      Reductive deamination.

    • E. 

      Transamination.

  • 11. 
    The conversion of glutamate to an alpha-ketoacid and NH4+:
    • A. 

      Does not require any cofactors.

    • B. 

      Is a reductive deamination.

    • C. 

      Is accompanied by ATP hydrolysis catalyzed by the same enzyme.

    • D. 

      Is catalyzed by glutamate dehydrogenase.

    • E. 

      Requires ATP.

  • 12. 
    Which of the following conversions require more than one step? 1. Alanine --> pyruvate 2. Aspartate --> oxaloacetate 3. Glutamate --> ketoglutarate 4. Phenylalanine --> hydroxyphenylpyruvate 5. Proline --> glutamate
    • A. 

      1 and 4

    • B. 

      1, 2 and 4

    • C. 

      1, 3 and 5

    • D. 

      2, 4 and 5

    • E. 

      4 and 5

  • 13. 
    Urea synthesis in mammals takes place primarily in tissues of the:
    • A. 

      Brain.

    • B. 

      Kidney.

    • C. 

      Liver.

    • D. 

      Skeletal muscle.

    • E. 

      Small intestine.

  • 14. 
    Which substance is not involved in the production of urea from NH4+ via the urea cycle?
    • A. 

      Aspartate

    • B. 

      ATP

    • C. 

      Carbamoyl phosphate

    • D. 

      Malate

    • E. 

      Ornithine

  • 15. 
    Which of these directly donates a nitrogen atom for the formation of urea during the urea cycle?
    • A. 

      Adenine

    • B. 

      Aspartate

    • C. 

      Creatinine

    • D. 

      Glutamate

    • E. 

      Ornithine

  • 16. 
    Conversion of ornithine to citrulline is a step in the synthesis of:
    • A. 

      Aspartate.

    • B. 

      Carnitine.

    • C. 

      Pyruvate.

    • D. 

      Tyrosine.

    • E. 

      Urea.

  • 17. 
    In the urea cycle, ornithine transcarbamoylase catalyzes:
    • A. 

      Cleavage of urea to ammonia.

    • B. 

      Formation of citrulline from ornithine and another reactant.

    • C. 

      Formation of ornithine from citrulline and another reactant.

    • D. 

      Formation of urea from arginine.

    • E. 

      Transamination of arginine.

  • 18. 
    Which of the following statements is false in reference to the mammalian synthesis of urea?
    • A. 

      Krebs was a major contributor to the elucidation of the pathway involved.

    • B. 

      The amino acid arginine is the immediate precursor to urea.

    • C. 

      The carbon atom of urea is derived from mitochondrial HCO3–.

    • D. 

      The precursor to one of the nitrogens of urea is aspartate.

    • E. 

      The process of urea production is an energy-yielding series of reactions.

  • 19. 
    Which of the following amino acids are essential for humans?
    • A. 

      Alanine

    • B. 

      Aspartic acid

    • C. 

      Asparagine

    • D. 

      Serine

    • E. 

      Threonine

  • 20. 
    If a person's urine contains unusually high concentrations of urea, which one of the following diets has he or she probably been eating recently?
    • A. 

      High carbohydrate, very low protein

    • B. 

      Very high carbohydrate, no protein, no fat

    • C. 

      Very very high fat, high carbohydrate, no protein

    • D. 

      Very high fat, very low protein

    • E. 

      Very low carbohydrate, very high protein

  • 21. 
    Which of these amino acids can be directly converted into a citric acid cycle intermediate by transamination?
    • A. 

      Glutamic acid

    • B. 

      Serine

    • C. 

      Threonine

    • D. 

      Tyrosine

    • E. 

      Proline

  • 22. 
    Which of these amino acids are both ketogenic and glucogenic? 1. Isoleucine 2. Valine 3. Histidine 4. Arginine 5. Tyrosine
    • A. 

      1 and 5

    • B. 

      1, 3, and 5

    • C. 

      2 and 4

    • D. 

      2, 3, and 4

    • E. 

      2, 4, and 5

  • 23. 
    Tetrahydrofolate (THF) and its derivatives shuttle ______________ between different substrates.
    • A. 

      Electrons

    • B. 

      H+

    • C. 

      Acyl groups

    • D. 

      One carbon units

    • E. 

      NH2 groups

  • 24. 
    The amino acids serine, alanine, and cysteine can be catabolized to yield:
    • A. 

      Fumarate.

    • B. 

      Pyruvate.

    • C. 

      Succinate.

    • D. 

      Alpha-ketoglutarate.

    • E. 

      None of the above.

  • 25. 
    Serine or cysteine may enter the citric acid cycle as acetyl-CoA after conversion to:
    • A. 

      Oxaloacetate.

    • B. 

      Propionate.

    • C. 

      Pyruvate.

    • D. 

      Succinate.

    • E. 

      Succinyl-CoA