UNE Biochemistry Final Test | questions with 100% Correct Answers Rated A+ The glucose -alanine cycle is a method of transferring ammonia from the skeleta l muscle to the liver. In this process the non -toxic carrier of ammonia is which of the following compounds? - Ans Alanine Which of the following enzymes is correctly paired with its activator? - Ans N -acetylglutamate synthatase; arginine The urea cycle takes place in which of the following subcellular locations? - Ans the cytosol and the mitochondria Which of the following enzymes is regulated by N -acetylglutamate (NAGs)? - Ans CPS I Which of the following enzymes is the regulatory step in the urea cycle? - Ans Carbamoyl phosphate synthetase I (CPS I) Which of the following statements is consistent with nitrogen transport in the fasted state? - Ans The urea cycle will be active A com atose 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 like ly diagnosis? - Ans Ornithine transcarbamoylase 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? - Ans Increased am ino acids in the blood The cellular uptake of LDL increases intracellular cholesterol levels. This has which of the following impacts on de novo cholesterol synthesis? - Ans Increases degradation of HMG -CoA reductase Dietary cholesterol is primarily tran sported in the body by which of the following lipoproteins? - Ans Chylomicron Secondary bile salts are generated by bacterial modification of primary bile salts in the intestinal lumen. These modifications have which of the following impacts on bile salt solubility? - Ans Decrease solubility A 47 -year -old male is prescribed a statin (HMG -CoA reductase inhibitor) to manage his elevated LDL cholesterol. What is the initial mechanism of action for obtaining the desired effect in this man? - Ans Decreasing he patic cholesterol biosynthesis A deficiency in the LDL receptor will result in an initial decrease in which of the following? - Ans Intracellular cholesterol A 45 -year -old man has a mild heart attack and a history of vascular disease. He is placed on a Mediterranean diet and statin drug therapy. Which of the following will be the most likely result of this drug therapy? - Ans Low blood LDLs A 45 -year -old man is found to have an elevated serum triglycerides of > 730mg/dL. He tells you he forgot to fast be fore his visit and he ate a full breakfast of bacon and eggs before the labs were drawn. Which of the following lipoproteins would be the largest contributors to a measurement of plasma triglycerides in this situation? - Ans Chylomicrons and VLDLs In the reaction catalyzed by cholesterol ester transfer protein (CETP), the VLDL particle receives which of the following compounds from HDL particles? - Ans Cholesterol -ester In reverse cholesterol transport HDL interacts with the ABCA1 transporter to move chol esterol from the cell to the HDL. This also requires the activity of which of the following enzyme? - Ans Lecithin cholesterol acyltransferase (LCAT) HDL particles interact with VLDL particles to exchange cholesterol ester for triacylglyerols. Which of th e following enzymes is responsible for this process? - Ans Cholesterol ester transfer protein (CETP) Which of the following is a major source of extracellular cholesterol for human tissues? - Ans LDLs An individual is suspected of having a deficiency in branched chain keto acid dehydrogenase. Supplementation of which of the following vitamins or cofactor s may help resolve this issue? - Ans Thiamine A 55 -year old man presents to his primary care physician with bouts of dizziness and confusion. He is diagnosed with hyperhomocysteinemia due to a deficiency of cystathionine -ß synthase. In this individual whi ch of the following amino acids could potentially become essential? - Ans Cysteine Phenylketonuria can be caused by an enzymatic deficiency or it can present due to a deficiency in which of the following required metabolic cofactors? - Ans Tetrahydrobiopt erin (BH4) A 17 -year old female presents to her primary care and is diagnosed with a Vitamin B12 (cobalamin) deficiency. In this individual, which of the following reactions would be compromised? - Ans Conversion of methyl malonyl -Co A to succinyl -CoA 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 deficien cy. Based on this information, metabolism of which of the following amino acids is likely impaired? - Ans Tryptophan
acetylglutamate (NAGs). Which of the following would be a consequence of this deficiency in the patient? - Ans Increased am ino acids in the blood The cellular uptake of LDL increases intracellular cholesterol levels. This has which of the following impacts on de novo cholesterol synthesis? - Ans Increases degradation of HMG -CoA reductase Dietary cholesterol is primarily tran sported in the body by which of the following lipoproteins? - Ans Chylomicron Secondary bile salts are generated by bacterial modification of primary bile salts in the intestinal lumen. These modifications have which of the following impacts on bile salt solubility? - Ans Decrease solubility A 47 -year -old male is prescribed a statin (HMG -CoA reductase inhibitor) to manage his elevated LDL cholesterol. What is the initial mechanism of action for obtaining the desired effect in this man? - Ans Decreasing he patic cholesterol biosynthesis A deficiency in the LDL receptor will result in an initial decrease in which of the following? - Ans Intracellular cholesterol A 45 -year -old man has a mild heart attack and a history of vascular disease. He is placed on a Mediterranean diet and statin drug therapy. Which of the following will be the most likely result of this drug therapy? - Ans Low blood LDLs A 45 -year -old man is found to have an elevated serum triglycerides of > 730mg/dL. He tells you he forgot to fast be fore his visit and he ate a full breakfast of bacon and eggs before the labs were drawn. Which of the following lipoproteins would be the largest contributors to a measurement of plasma triglycerides in this situation? - Ans Chylomicrons and VLDLs In the reaction catalyzed by cholesterol ester transfer protein (CETP), the VLDL particle receives which of the following compounds from HDL particles? - Ans Cholesterol -ester In reverse cholesterol transport HDL interacts with the ABCA1 transporter to move chol esterol from the cell to the HDL. This also requires the activity of which of the following enzyme? - Ans Lecithin cholesterol acyltransferase (LCAT) HDL particles interact with VLDL particles to exchange cholesterol ester for triacylglyerols. Which of th e following enzymes is responsible for this process? - Ans Cholesterol ester transfer protein (CETP) Which of the following is a major source of extracellular cholesterol for human tissues? - Ans LDLs An individual is suspected of having a deficiency in branched chain keto acid dehydrogenase. Supplementation of which of the following vitamins or cofactor s may help resolve this issue? - Ans Thiamine A 55 -year old man presents to his primary care physician with bouts of dizziness and confusion. He is diagnosed with hyperhomocysteinemia due to a deficiency of cystathionine -ß synthase. In this individual whi ch of the following amino acids could potentially become essential? - Ans Cysteine Phenylketonuria can be caused by an enzymatic deficiency or it can present due to a deficiency in which of the following required metabolic cofactors? - Ans Tetrahydrobiopt erin (BH4) A 17 -year old female presents to her primary care and is diagnosed with a Vitamin B12 (cobalamin) deficiency. In this individual, which of the following reactions would be compromised? - Ans Conversion of methyl malonyl -Co A to succinyl -CoA 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 deficien cy. Based on this information, metabolism of which of the following amino acids is likely impaired? - Ans Tryptophan
