UNE FINAL BIOCHEM TEST QUESTIONS WITH CORRECT SOLUTIONS, GRADED A+

What are the main products of beta oxidation? - 1 NADH, 1 FADH, 1 Acetyl CoA So in the case of an 11-year-old girl brought to the emergency department by her father, he's reporting that she's been very thirsty and needing to make frequent strips to the bathroom. Today, she reported lightheadedness during a soccer game and symptoms did not resolve after drinking a power beverage. A rapid dipstick test revealed glucose in her urine and further diagnosis are consistent with a diagnosis of type I diabetes. So evaluation of this girl's liver would reveal an increased rate in which of the following processes? A. Fatty Acid Synthesis B. Glycogenesis C. Glycolysis D. Ketogenesis E. Protein Synthesis - D. Ketogenesis A 5 year old female brought to the Emergency Department by her mother, and she's a Type 1 diabetic and has not taken her insulin while she's been away, the child is unresponsive, and we ask the question, which of the following enzymes is phosphorylated and active under these conditions? A. Acetyl- CoA Carboxylase B. Hormone Sensitive Lipase C. Glycogen Synthase D. Phosphofructokinase 2 E. Pyruvate Kinase - B. Hormone Sensitive Lipase An individual goes to bed around 8pm and doesn't wake up until 9am the next morning. During this time, which of the following is the primary oxidizable substrate in the skeletal muscle? - Free Fatty Acids During the fasted state, lipolysis is facilitated by the action of hormone sensitive lipase. This enzyme requires which of the following modifications for activation? - Phosphorylation A well, 2-year-old girl presents to the clinic with symptoms of a viral illness. Her parents report she has had bouts of vomiting and diarrhea over the last 24 hours. This morning they could barely wake her from her crib and she was very weak. Laboratory tests show low blood glucose (hypoglycemia) and elevated liver enzymes. There are no ketones in her urine. The child is hospitalized and glucose is administered by I.V. Additionally laboratory analysis showed elevated medium-chain fatty acyl carnitines in blood and 6-8 carbon dicarboxylic acids in the urine. What is her diagnosis? - defect of medium-chain coenzyme A dehydrogenase Under fasting conditions (ratio of insulin to glucagon 1), elevated glucagon will activate which of the following enzymes? - Hormone Sensitive Lipase Ketonuria, hyperglycemia and severe acidosis are prime 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 of a patient in this condition? - D-3-hydroxybutyrate and acetoacetate In liver, which of the following key inhibitory events ensures that newly synthesized palmitoyl-CoA is not immediately oxidized? - Inhibition of acyl-CoA by malonyl-CoA In the fasted state, fatty acyl-CoAs are transported across the mitochondrial membrane. The transport of fatty acids via carnitine palmitoyl transferase I (CPTI) can be directly inhibited by which of the following compounds? - Malonyl-CoA An individual is on a hunger strike and has not eaten in 13 days. Which of the following best describes their metabolic state? - The brain will be preferentially oxidizing ketones An increase in the ratio of insulin to glucagon will increase the activity of which of the following enzymes (+ indicates activity is increased; - indicates activity is not increased by insulin)? 1.Hormone sensitive lipase 2. Acetyl-CoA carboxylase 3. Phosphofructokinase-2 (PFK2) 4. Glycogen synthase - (-) hormone sensitive lipase (+) acteyl- CoA Carboxylase (+) phosphofructokinase -2 (+) Glycogen synthase Fatty acid synthase is a multimeric enzyme complex. Which of the following subunits contains pantothenic acid as a cofactor? - Acyl Carrier Protein (ACP) Malate can be converted to pyruvate in the cytosol. Which of the following compounds is directly generated in this conversion and is essential for fatty acid synthesis? - NADPH NADPH is essential for fatty acid synthesis and can be generated by which two enzymes? (+ indicates NADPH can be produced by the enzyme; - indicates the enzyme does not produce NAPDH) 1. Glucose 6-phosphate dehydrogenase 2. Malic enzyme 3. Pyruvate dehydrogenase complex - (+) Glucose 6-phosphate dehydrogenase (+) Malic enzyme (-) Pyruvate dehydrogenase complex