UNE Biochem 1005 Unit 2 Exam Latest Questions With Correct Solutions.

UNE Biochem 1005 Unit 2 Exam Latest Questions With Correct Solutions. 1. Pyruvate dehydrogenase kinase catalyzes a reaction that results in which of the following? The phosphorylation and inactivation of E1 subunit (pyruvate dehydrogenase complex 1. Which of the following intermediates is an allosteric activator of pyruvate kinase? a. Fructose 1.6 bisphosphate 1. Which of the following is the initial second messenger in the signaling cascade initiated by glucagon? a. cAMP 1. Hereditary fructose intolerance in caused by a deficiency in aldolase B. These individuals may present with hypoglycemia due to an accumulation of fructose 1-P in the cell and inhibition of which of the following pathways? a. Gluconeogenesis and glycogenolysis 1. Following insulin binding its receptor and autophosphorylation of the beta chain, what is the initial step in the cascade of events? a. Recruitment of the insulin receptor substrate 1. What sequence of enzymes allows for the synthesis of glycogen from glucose 6-P? Phosphoglucomutase, UDP-glucose phosphorylase, glycogen synthase amylo-(1,4a1,6)-transglycosylase 1. Complex II, succinate dehydrogenase, is not considered to be part of the process of oxidative phosphorylation because it is unable to do which of the following activities? a. Pump protons from the mitochondrial matrix to the intermembrane space 1. Which of the following is the primary GLUT transporter in skeletal muscle and adipose tissue? GLUT 4 1. Which of the following best describes the net effect of the 8 steps of the TCA cycle? a. This process completely oxidizes an acetyl group to carbon dioxide 1. Which of the following enzymes is correctly paired with this activator? a. Pyruvate dehydrogenase complex, pyruvate 1. ATP is a high energy molecule that is often hydrolyzed during reactions. The energy within ATP is stored primarily in which of the following compounds of the molecule? a. In the high energy phosphate bonds 1. Which of the following is a key inhibitor of the a-ketoglutarate dehydrogenase? NADH 1. As electrons flow through complexes in the inner mitochondrial membrane, protons are pumped from the matrix to the intermembrane space. Which of the following statements is most reflective of the pH in the intermembrane space? a. The pH is higher in the matrix when compared to the intermembrane space 1. Pyruvate dehydrogenase complex is highly regulated. The enzyme will be most active when which of the following compounds is high? Pyruvate 1. TCA cycle intermediates are always being removed for various metabolic processes. One example of this is the removal of succinyl CoA which is used for the synthesis of which of the following compounds? Heme 1. The fully reduced quinol form of CoQ contains which of the following combinations of electrons and protons? 2 e- and two protons 1. Individuals with a deficiency in glucose 6-P dehydrogenase often present with hemolytic anemia. This is primarily due to a deficiency in which of the following metabolic products? NADPH 1. Within the red blood cell, glucose can be oxidized to which of the following products? lactate and ribose 5- phosphate 1. Which of the following is an inhibitor of isocitrate dehydrogenase and a-ketoglutarate dehydrogenase? a. NADH 1. The non-oxidative stage of the pentose phosphate pathway produces substances that are intermediates of ____? Glycolysis 1. The glycerol 3-P shuttle is the major shuttle of most tissues. Which of the following best describes the transfer of electrons by this shuttle? a. Electrons are directly transferred from glycerol 3-P to an FAD containing glycerol phosphate dehydrogenase 1. Glycogen degradation in the liver can be enhanced by the activation of alpha-adrenergic receptors by epinephrine. The initial step in this cascade involves which of the following second messengers or active enzymes? a. Phospholipase C 1. Which of the following enzymes is involved in the non-oxidative portion of the pentose pathway? Transketolase 1. Heme can inhibit its own synthesis by inhibiting the activity of which of the following enzymes? a. Aminolevulinic acid synthase 1. Under low energy conditions, AMP will bind to phosphofructokinase-1 and glycogen phosphorylase. This is an example of which of the following types of enzyme regulation? a. Allosteric activation 1. Activation of glycogen phosphorylase is regulated in several manners. In skeletal muscle, which of the following compounds can allosterically activate the enzyme? a. AMP 1. Insulin stimulates fatty acid synthesis in the liver. These fatty acids are transported to the adipose tissue as which of the following? VLDL particles 1. Calcium can increase flux thru the TCA cycle by stimulating the activity of the following enzymes except? succinate thiokinase 1. A deficiency in the enzyme fructokinase will lead to all of the following clinical presentations except: hypoglycemia 1. Under anaerobic conditions, glucose is primarily oxidized to which of the following compounds? Lactate 1. The order of prosthetic groups as they act in the three proteins of the PDC is: TPP, lipoid acid (lipoate), FAD 1. Which of the following describes the correct and complete electron transfer pathway necessary for oxidative phosphorylation? a. NADH - complex I - CoQ- complex III cyt c- complex IV 1. Which of the following allosterically activates mammalian isocitrate dehydrogenase? ADP 1. Cortisol is a steroid hormone and it signals via which of the following mechanisms? a. Nuclear receptor 1. In the malate aspartate shuttle, glutamate is converted to ___ in the mitochondria while aspartate is converted to __ in the cytosol? alpha-ketoglutarate; oxaloacetate 1. The last cytochrome in the ETC, cytochrome oxidase, passes electrons to molecular oxygen. Cytochrome oxidase is able to do this because it has: Lower Km for oxygen than hemoglobin 1. Which of the following reactions is commonly used to replenish intermediates of the TCA cycle? a. Glutamate a ketoglutarate 1. Glucagon binds a G-Protein coupled receptor. Which of the following second messengers is generated by this cascade of events? cAMP 1. A deficiency in glucose 6-p dehydrogenase reduces the levels of NADPH in the red blood cell. This leads to an increase in which of the following compounds of the cell? a. Oxidized glutathione 1. Dinitrophenol is an uncoupler of the ETC. The addition of dinitrophenol will have which of the following impacts? increased oxygen consumption 1. The malate aspartate shuttle is used to move reducing equivalents from cytosolic NADH into the mitochondria where it can be oxidized. Which of the following compounds is used to move the reducing equivalents from cytosolic NADH into the mitochondria? malate Heme synthesis requires succinyl CoA as a substrate. The end product of this pathway is heme which can regulate its own synthesis by having which of the following impacts on the regulatory enzyme? functioning as a feedback inhibitor of the enzyme 1. What is the primary oxidized fuel in skeletal muscle in the fasted state? a. Free fatty acids 1. Sucrase is the digestive enzyme for metabolizing sucrose. It does this by cleaving the bonds between dimers of which monosaccharides? a. Glucose and fructose 1. Heat can be generated in the brown adipose tissue of hibernating mammals due to which of the following processes? uncoupling of the ETC by thermogenin 1. When glucagon binds to its receptor on a liver cell, which of the following sequence of events occurs to activate protein kinase A? a. Activation of G protein, activation of adenylate cyclase, production of cAMP 1. The synthesis of large molecules from smaller compounds is an example of what type of work? biochemical 1. Which of the following directly provides oxidizable substrate to RBCs during the fasted state? a. Glycogenolysis 1. Which step in the citric acid cycle is a rearrangement reaction? citrate to isocitrate 1. Cortisol is a steroid hormone that increases protein catabolism from skeletal muscle. It does this through which of the following mechanisms? transcriptional regulation 1. Pyruvate dehydrogenase kinase will facilitate which of the following reactions? the pyruvate dehydrogenase kinase will phosphorylate and inactivate the pyruvate dehydrogenase complex 1. A-ketoglutarate dehydrogenase is the enzyme responsible for one of the irreversible reactions in the TCA cycle. The enzyme catalyzes which of the following conversions? a-ketoglutarate to succinyl coA 1. The major regulatory step pf the pentose phosphate pathway is catalyzed by which enzyme? a. Glucose 6 phosphate dehydrogenase 1. Aldolase B facilitates a reaction that cleaves fructose 1-phosphate into dihydroxyacetone-phosphate and what other glycolytic intermediate? a. Glyceraldehyde 3-Phosphate 1. The reduction of NAD+ is often coupled to the oxidation of an alcohol. In this reaction, NAD+ obtains which of the following from the oxidized compound? a. Two electrons as a hydride ion 1. In the case of an exothermic reaction: Delta G0 would be negative