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Intro to Urea Cycle quiz

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  • What is the main function of the urea cycle?
    The urea cycle converts toxic ammonium ions into urea for excretion in urine.
  • What type of pathway is the urea cycle in terms of energy?
    The urea cycle is an energy-consuming (energy-spending) pathway that uses ATP.
  • Which molecule undergoes oxidative deamination to produce ammonium ions for the urea cycle?
    Glutamate undergoes oxidative deamination to produce ammonium ions.
  • Where is urea produced in the cell during the urea cycle?
    Urea is produced in the cytosol at the end of the urea cycle.
  • Describe the structure of a urea molecule.
    Urea has a carbonyl group flanked by two NH2 (amino) groups.
  • Where are ammonium ions prepared for entry into the urea cycle?
    Ammonium ions are prepared in the mitochondrial matrix.
  • How many phases does the urea cycle have and what are they called?
    The urea cycle has two phases: Phase A (preparation) and Phase B (conversion).
  • What happens during Phase A of the urea cycle?
    In Phase A, ammonium ions are converted into carbamoyl phosphate using ATP and carbon dioxide.
  • Which organelle is involved in the preparation phase of the urea cycle?
    The mitochondrial matrix is involved in the preparation phase.
  • What is the main product of Phase B in the urea cycle?
    The main product of Phase B is urea.
  • Which two molecules are used to produce urea in Phase B?
    Carbamoyl phosphate and aspartate are used to produce urea in Phase B.
  • Does Phase B of the urea cycle require ATP?
    Yes, Phase B also consumes ATP.
  • What is the fate of the urea produced by the urea cycle?
    The urea is excreted from the body in urine.
  • What is the source of carbon dioxide used in the urea cycle?
    Carbon dioxide used in the urea cycle comes from the mitochondrial matrix.
  • Why is the urea cycle important for the body?
    The urea cycle is important because it detoxifies ammonium ions, preventing their accumulation in the body.