UNE biochem unit 4 multiple choice questions and answers correctly explained.

UNE biochem unit 4 multiple choice questions and answers correctly explained. Which of the following non-essential amino acids is synthesized as part of the urea cycle? - correct answers.Arginine Which of the following reactions of the urea cycle takes place in the mitochondria? - correct answers.The synthesis of carbamoyl phosphate The transamination of all amino acids requires which of the following cofactors? - correct answers.Pyridoxal phosphate (PLP) A comatose infant is brought to the ER. In the course of the examination, plasma ammonia was found to be elevated 20-fold over normal values. Urine orotic acid and uracil were both greater than normal. A defect of which of the following enzymes is the most likely diagnosis? - correct answers.Ornithine transcarbamoylase Which of the following enzymes is likely to be active in both the fed and fasted states? - correct answers.Glutaminase The reaction of ammonia with α-ketoglutarate is catalyzed by _________ and requires _________ as a reactant. - correct answers.Glutamate dehydrogenase; NADH or NADPH Which of the following enzymes is regulated by N-acetylglutamate (NAGs)? - correct answers.Carbamoyl phosphate synthetase I (CPS I) Your patient presents with a deficiency of the enzyme that catalyzes synthesis of N-acetylglutamate (NAGs). Which of the following would be a consequence of this deficiency in the patient? - correct answers.Increased amino acids in the blood Homocystinuria can be caused by several different enzyme or vitamin deficiencies. An elevation of homocysteine and a decrease in cysteine would most likely present due to which of the following deficiencies? - correct answers.Loss of function of cystathionine-β synthase A 15-year-old female presents to her pediatrician with concerns over her inability to sleep, increased feelings of depression and generalized fatigue. A full laboratory work-up is ordered and based on these findings she is diagnosed with a melatonin deficiency. Based on this information, metabolism of which of the following amino acids is likely impaired? - correct answers.Tryptophan In an individual with a deficiency in the branched chain ketoacid dehydrogenase complex, metabolism of which of the following amino acids would not likely be impaired? - correct answers.Tyrosine A 52-year- old male sought medical help complaining about progressive appearance of hyperchromic (hyper pigmented) papules on the edge of the second finger of both hands. He also complained about darkening of urine. Incisional biopsy of one of the spots on his hands and urine sample tested positive for or homogentisic acid. Based on these findings a diagnosis of alkaptonuria is made. This diagnosis is consistent with a deficiency in which of the following enzymes? - correct answers.Homogentisate oxidase Which of the following compounds or substrates is required for the synthesis of tyrosine? (+ indicates the compound is required; - indicates the compound is not required) (THF) (BH4) Tryptophan Phenylalanine 1. + + + - 2. - + + - 3. + - - + 4. - + - + - correct answers.4 An individual is suspected of having a deficiency in branched chain keto acid dehydrogenase. Supplementation of which of the following vitamins or cofactors may help resolve this issue? - correct answers.Thiamine A 2-day-old infant test positive for hyperphenylalaninemia. This is most likely caused by a heritable defect in which of the following enzymes? - correct answers.Phenylalanine hydroxylase A deficiency in B6 (pyridoxal phosphate) would negatively impact which of the following pathways: 1. Metabolism of homocysteine to cysteine 2. Metabolism of phenylalanine to tyrosine 3. Conversion of methyl malonyl-CoA to succinyl-CoA - correct answers.1 only