Unit 4 test UNE medical biochemistry Exam Questions With 100% Correct Answers

Unit 4 test UNE medical biochemistry Exam Questions With 100% Correct Answers A deficiency in which of the following enzymes will NOT result in an increase in orotic acid? a. N-acetylglutamate synthetase b. Ornithine transcarbamoylase c. Argininosuccinate synthetase d. Argininosuccinate lyase - answerN-acetylglutamate synthetase (NAG synthetase Feedback: deficiencies in NAG synthetase or carbamoyl phosphate synthetase I will NOT result in an increase in orotic acid. Which of the following enzymes is correctly paired with its activator? a. N-acetylglutamate synthtase; arginine b. Carbamoyl phosphate synthetase I; ATP c. Glutaminase; citrate d. Arginase; NADH - answerN-acetylglutamate synthtase; arginine Feedback: arginine (an intermediate of the urea cycle), stimulates the synthesis of NAG by allosterically activating the enzyme N-acetylglutamate synthase Which of the following enzymes is regulated by N-acetylglutamate (NAGs)? a. Carbamoyl phosphate synthetase II b. Ornithine transcarbamoylase c. Carbamoyl phosphate synthetase I d. Arginosuccinate lyase - answerCarbamoyl phosphate synthetase I (CPS I) Feedback: CPS I is the regulatory enzyme of the urea cycle and is stimulated by NAG Your patient presents with a deficiency of the enzyme that catalyzes synthesis of N- acetylglutamate (NAGs). Which of the following will be a consequence of this deficiency in the patient? a. increased fatty acids in the blood b. increased amino acids in the blood c. decreased excretion of uric acid d. increased glucose in the blood - answerIncreased amino acids in the blood NAG is an essential activator of CPS I which catalyzes the first step in the urea cycle. Loss of this activator will decrease urea cycle activity, which will increase the amount of amino acids in the blood. The urea cycle takes place in which of the following subcellular locations? a. the cytosol and the mitochondria b. the cytosol only c. the nucleus and the mitochondria d. the mitochondria only - answerthe cytosol and the mitochondria Which of the following non-essential amino acids is synthesized as part of the urea cycle? a. Asparagine b. Aspartate c. Lysine d. Arginine e. Glutamine - answerarginine Several amino acids are intermediates of the urea cycle, having side ammonia groups that join with free Co2 and ammonia to produce net excretion of ammonia as urea. Which of the following amino acids has a nitrogen in its side chain AND is an intermediate of the urea cycle? a. asparagine