UNE medical biochemistry Unit 2 Test

UNE medical biochemistry Unit 2 Test If unregulated, which of the following pairs of enzymes would represent a futile cycle? Fructose 1,6 bisphosphatase and phosphofructokinase-1 Rotenone blocks complex 1 in the ETC. This increases levels of NADH and would likely impair the function of which of the following enzymes? Pyruvate dehydrogenase complex Newborn screening shows a biotinidase deficiency in a 2-day old infant. This deficienty impairs the infant's ability to reuse and recycle biotin. Due to this enzymatic deficiency, the activity of which of the following enzymes is likely impaired? pyruvate carboxylase An individual is recently diagnosed with Type 2 diabetes. In this individual, hyperglycemia may in part be due to inactivity of which of the following glucose transporters on skeletal muscle? Glut 4 (insulin dependent) The skeletal muscle primarily provides substrate for gluconeogenesis through which of the following processes? protein catabolism Alanine can be shuttled from the skeletal muscle to the liver where it is deaminated to produce pyruvate. When glucagon is high, pyruvate is primarily used as a substrate for which of the following pathways? gluconeogenesis Aldolase B facilitaes a reaction that cleaves fructose 1-phosphate into two 3-carbon molecules that will enter glycolysis as which of the following compounds? glyceraldehyde-3-phosphate Within the RBC, NADPH is used for which of the following processes? to re-reduce glutathione Galactose-1-phosphate is initially converted to glucose-1-phosphate and requires which of the following compounds? UDP-glucose Which of the following are the two primary products of the Pentose Phosphate pathway? Ribose-5-phosphate and NADPH Which of the following enzymes is involved in the non-oxidative portion of the Pentose Phosphate Pathway? transaldolase A patient presents with a deficiency of thiamine. If this patient's liver cells are compared to normal liver cells, which of the following products would be decreased in the patient's cells (compared to the normal cells), if the cells are only given glucose as a fuel? CO2 (lack of thiamine would reduce activity of PDC - as a result, most pyruvate would be diverted to lactate instead of acetyl-CoA) Which of the following best describes the net effect of the 8 steps of the TCA cycle? The process completely oxidizes an acetyl group to carbon dioxide Which of the following compounds allosterically activates phosphofructokinase-1 (PFK1)? fructose 2,6-bisphosphate Which of the following enzymes is correctly paired with it's activator? pyruvate dehydrogenase; pyruvate A newborn male is diagnosed with congenital lactic acidosis because of a defective electron transport protein. This deficiency leads to a decrease in the rate at which NADH and FADH2 can be oxidized to produce ATP via oxidative phosphorylation and results in an increase in cytosolic AMP. Under these conditions, which glycolytic enzyme would be stimulated? phosphofructokinase-1 (PFK-1 is activated by high cytosolic AMP and inhibited by AMP) Which of the following outlines the order of prosthetic groups as they are used for catalysis within the PDC? thiamine diphosphate lipoamide FAD Which of the following intermediates of the TCA cycle is required in the cytosol for fatty acid synthesis? citrate (in the cytosol, citrate is cleaved by citrate lyase back into oxaloacetate and acetyl CoA) Which of the following enzymes is responsible for the degradation of cAMP phosphodiesterase Following insulin binding its receptor and autophosphorylation of the beta chain, what is the initial step in this cascade of events? recruitment of the insulin receptor substrate (IRS) Steroid hormones bind to which of the following types of receptors? intracellular receptorsF Shortly after a meal, there will be increased activity in which metabolic pathway as a result of increased insulin? glycolysis Order the following statements to illustrate the correct cascade of events that occurs after ligand binding of G-protein coupled receptor 3: G-protein exchanges GDP for GTP 2: dissociation of beta and gamma subunits 4: activation of adenylyl cyclase to generate cAMP 1: degredation of cAMP by phosphodiesterase Which of the following is a characteristic of all receptors? they are specific to a chemical messenger Mnemonic - TCA cycle intermediates (krebs/citric acid cycle) "Can I Keep Selling Sex for Money, Officer?" C- citrate I- isocitrate K - a-ketoglutarate S- succinyl coA S- succinate F - fumrate M - malate O - oxaloacetate Mnemonic - enzymes of Glycolysis "Harry Potter Practically Always Tries Ginny Potter's Patience Every Practice" H- hexokinase P- phosphoglucoisomerase P- PFK-1 (phosphofructokinase-1) A- aldolase