Final Exam Review UNE medical biochemistry Questions & Answers Rated 100% Correct!!

Final Exam Review UNE medical biochemistry Questions & Answers Rated 100% Correct!! Under fasting conditions (ratio of insulin: glucagon 1), elevated glucagon will activate which of the following enzymes? hormone sensitive lipase Ketonuria, hypoglycemia, 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 of urine of a patient in this condition? D-3-hydroxybutyrate and acetoacetate What is the purpose of cholesterol esterification within the cell? (the conversion of cholesterol to cholesteryl ester) a. this modification makes cholesterol more soluble in the plasma membrane b. this modification does not change the chemical properties of cholesterol c. esterification is the first step in the synthesis of cortisol d. esterification traps cholesterol in the cell esterification traps cholesterol in the cell 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 in the skeletal muscle? a. free fatty acids b. glycogen c. amino acids d. lactate free fatty acids A 22-year-old woman engaging in a political protest goes on a hunger strike on a prominent corner in a city park. She refuses all offers of food for except for water through the first 2 weeks. Under these conditions there is a decreased reliance on which of the following pathways for fuel? a. β-oxidation b. ketogenesis c. gluconeogenesis d. lipolysis gluconeogenesis In reverse cholesterol transport HDL interacts with the ABCA1 transporter to move cholesterol from the cell to the HDL. This also requires the activity of which of the following enzyme? a. lipoprotein lipase b. cholesteryl ester transfer protein (CETP) c. lecithin cholesterol acyltransferase (LCAT) d. LDL receptor lecithin cholesterol acyltransferase (LCAT) A 16-year-old woman presents to her primary care physician for a follow up visit. At her initial visit, 3 months ago, her serum cholesterol was 255 mg/dL (above normal). She finds this very disappointing as she started a strict dietary regime reducing all fats and cholesterol, replacing them with a high carbohydrate diet. You tell her that high carbohydrate diets can increase serum triglyceride levels in some individuals. This can be attributed in an increase in the synthesis of which of the following lipoproteins? a. chylomicrons b. VLDL c. IDL d. HDL e. LDL VLDL a 5-year-old presents to her primary care physician. Her mother is concerned due to persistent diarrhea which is worse when eating fatty foods. The child also has some clinical signs of a deficiency in fat-soluble vitamins. Based on this information the child likely has a deficiency in the ability to synthesize which of the following lipoproteins? a. chylomicrons b. VLDLs c. LDLs d. HDLs chylomicrons The interaction of chylomicorns with lipoprotein lipase is stimulated by which of the following Apo proteins? a. ApoB 100 b. Apo B 48 c. Apo C II d. Apo E Apo C II A defect in the thioesterase subunit of fatty acid synthase would impair which of the following activities of the enzyme complex? a. liberation of newly assembled palmitate from the enzyme b. priming of the enzyme iwth acetyl-CoA c. Liberation of Co2 from 3-ketoacyl synthase d. binding of malonyl-CoA to an SH group liberation of newly assembled palmitate from the enzyme An increase in the ratio of insulin to glucagon leads to which of the following metabolic shifts? a. acetyl-CoA carboxylase will become dephosphorylated and active b. cytosolic levels of malonyl-CoA will decrease c. hormone sensitive lipase will become dephosphorylated and active d. VLDL synthesis will decrease acetyl-CoA carboxylase will become dephosphorylated and active HDL particles interact with VLDL particles to exchange cholesterol ester for triacylglyerols. Which of the following enzymes is responsible for this process? a. cholesterol ester transfer protein (CETP) b. LCAT (lecithin cholesterol acyltransferase) c. ABCA 1 trasnporter d. HMG CoA reductase cholesterol ester transfer protein (CETP) The LDL receptor is also highly regulated in the cell. Which of the following proteins targets the LDL receptor for degradation? a. proprotein convertase subtilisin/kexin type 9 (PSK9) b. Acyl-CoA: cholesterol acyltransferase (ACAT) c. Cholesterol esterase transfer protein (CETP) d. AMPK kinase PSK 9 Feedback: PSK9 is a regulator of LDL receptor recycling. IT targets the receptors for degradation rather than allowing them to be recycled to the cell surface. 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? a. malonyl-CoA b. acyl-CoA c. acetyl-CoA d. succinyl-CoA malonyl-CoA Secondary bile salts lack a hydroxyl group when compared to primary bile salts. What is the consequence of the loss of the OH group? a. secondary bile salts are more soluble b. secondary bile salts are more readily resorbed in the intestinal lumen c. the loss of the OH group does not change their functionality d. secondary bile salts are less soluble secondary bile salts are less soluble 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? a. have no change on solubility b. increase solubility c. decrease solubility decrease solubility The cellular uptake of LDL increases intracellular cholesterol levels. This has which of the following impacts on de novo cholesterol synthesis? increases degredation of HMG CoA reductase Which of the following enzymes is correctly paired with its allosteric inhibitor? Acetyl-CoA carboxylase; palmitoyl-CoA Which of the following is the regulated step of lipogenesis in eukaryotes? carboxylation of acetyl-CoA The regulation of PRPP synthetase is critical in the production of both purines and pyrimidines. This enzyme is inhibited under which of the following conditions? When both GDP and ADP are elevated Which of the following enzymes is correctly paired with its activator?