UNE Biochem Final Exam 2023/2024

UNE Biochem Final Exam 2023/2024 A 3-year-old male is brought to the emergency department by his parents. He is unconscious on admittance and his blood glucose was 15 mg/dl, ( normal 75 - 105 mg/dl). Further testing showed this individual had a deficiency in carnitine. Based on this diagnosis you would also expect which of the following to be true with regards to metabolism: This patient would have elevated levels of circulating free fatty acids. A 7-year old female is recently diagnosed with type 1 diabetes. Laboratory testing shows elevated urinary glucose and ketones. Blood glucose levels were 250 mg/dL (normal range 90 -120 mg/dL). The increase in blood glucose in this individual is primarily due to increased activity of which of the following enzymes? Fructose 1,6 bisphosphatase Ketonuria, hyperglycemia and severe acidosis are diagnostic indicators of the presentation of type 1 diabetic ketoacidosis. Which of the following compounds are "ketone bodies" that would be elevated in serum and urine from a patient in this condition? Beta-Hydroxybutyrate and acetoacetate In the fasted state, fatty acyl-CoA is transported across the mitochondrial membrane. The transport of fatty acids via carnitine palmitoyltransferase I (CPTI) can be directly inhibited by which of the following compounds? Malonyl-CoA An individual goes to bed around 8 pm and doesn't wake up until 9 am the next morning. During this time, which of the following is the primary oxidizable substrate for skeletal muscle? Free fatty acids The process of ketogenesis refers to the conversion of acetyl-CoA to which of the following compounds? beta-hydroxybutyrate A 3-year-old male is brought to the emergency department with hypoglycemia following a brief seizure. His parents put him to bed the night before and he had not eaten much dinner. His urine tested positive for dicarboxylic acids, serum-free fatty acids are elevated and there were no detectable ketones in his blood or urine. In this individual, at the time of presentation his ratio of insulin to glucagon is: 1 The processes of -oxidation and fatty acid synthesis are regulated in such a manner that neither process is active at the same time. Which of the following enzymes required for fatty acid synthesis is paired with the correct activator? Acetyl-CoA carboxylase; citrate Following a meal, the ratio of insulin to glucagon will be 1. Which of the following compounds will be elevated to inhibit carnitine palmitoyltransferase I? Malonyl-CoA Which of the following enzymes require thiamine as a cofactor for activity? (yes, indicates cofactor is required for activity; no, indicates cofactor is not required) 2: No Yes Yes No Which of the following enzymes is correctly paired with its allosteric inhibitor? Acetyl-CoA carboxylase: palmitoyl-CoA Which of the following is the regulatory enzyme for fatty acid synthesis? Acetyl-CoA carboxylase Under conditions when glucose oxidation is elevated, the acetyl-CoA produced will allosterically activate which of the following enzymes leading to an increase in the production of oxaloacetate? Pyruvate carboxylase Acetyl-CoA Carboxylase will be active when which of the following hormones is elevated? Insulin During fatty acid synthesis, after the initial step involving acetyl-CoA, the fatty acid chain is elongated by the addition of which of the following compounds? Malonyl-CoA When citrate is shuttled out of the mitochondria for fatty acid synthesis, the initial reaction by citrate lyase generates which of the following products? Acetyl-CoA and oxaloacetate Which of the following best defines the role of an HDL? A lipoprotein responsible for the reverse transport of cholesterol to the liver Which of the following best describes the role of HDL particles? HDL particles are required for the transport of cholesterol from peripheral tissues to the liver Which lipoproteins is responsible for the process of reverse cholesterol transport (the movement of cholesterol from the peripheral tissues back to the liver)? HDL Synthesis of which of the following lipoproteins would be elevated after a carbohydrate-rich meal? VLDL In the reaction catalyzed by cholesteryl ester transfer protein (CETP), the VLDL particle receives which of the following compounds from HDL particles? Cholesteryl-ester Which of the following compounds is the primary component of a mature HDL? Cholesteryl-ester What is the primary lipid component of a nascent HDL particle? Phospholipids VLDL particles have which of the following combinations of apoproteins in their mature form? ApoB100, ApoCII, ApoE A patient's triglyceride levels are within normal limits, but their cholesterol is 350 mg/dl (normal: 200 mg/dl). The physician prescribes medication for this patient, which he states inhibits the enzyme HMG CoA reductase. The drug that was prescribed lowers circulating levels of cholesterol by: Decreasing hepatic cholesterol biosynthesis Cholesterol stimulates the activity of which of the following proteins required for bile acid synthesis? 7 alpha-hydroxylase Secondary bile salts lack a hydroxyl (OH) group when compared to primary bile salts. What is the consequence of the loss of this group? Secondary bile salts are less soluble Under fasted conditions, (glucagon is elevated), which of the following enzymes will be phosphorylated and inactive? HMG-CoA reductase In the event of a deficiency in ApoCII on VLDLs, which of the following processes would be impaired? Interaction of VLDL with lipoprotein lipase Which of the following compounds is not synthesized from cholesterol? Guanine A 45-year-old male has a mild heart attack and a history of vascular disease. He is placed on a Mediterranean diet and statin therapy. Which of the following will be the most likely result of this therapy? Low blood LDLs HMG CoA reductase is highly regulated within the cell. Which of the following will reduce the activity of HMG-CoA reductase? Phosphorylation by an insulin-activated protein kinase Which of the following statements is consistent with nitrogen transport in the fasted state? The urea cycle will be active A newborn infant was resuscitated at birth and was found to be neurologically compromised, with marked flaccidity (lack of muscle tone), and also to have cardiac insufficiency. Glutamine was largely absent from the serum, ammonia levels were excessively elevated and urea production was otherwise not impaired. Based on this information which of the following enzymes is likely deficient in this infant? Glutamine synthetase Which of the following statements is consistent with protein catabolism in the fed state? High levels of arginine will stimulate the activity of urea synthesis Which of the following enzymes is the regulatory step in the urea cycle? Carbamoyl phosphate synthetase I (CPS I) Consider the reaction shown below. Which stage of urea biosynthesis does the figure highlight? Transamination An infant starts to show signs of lethargy rapidly after birth. Upon evaluation, he is determined to have a deficiency in N-acetyl glutamate synthetase. Based on this information, which of the following would be consistent with this diagnosis? Decreased levels of carbamoyl phosphate Which of the following amino acids has a nitrogen in its side chain (R-group) and is an intermediate of the urea cycle? Arginine Which of the following is the primary role of glutaminase in the liver? To free an amine group from glutamine