Practice Exam IIID Derived from SS13 Exam IIIA 1 Please choose the True statement a The TCA cycle produces 3 molecules of NADH for every acetyl CoA group that enters the cycle b The TCA cycle takes place in the cytosol c Three carbon Acetyl Co A condenses with 3C citrate to produce the 6C intermediate isocitrate d The intermediate fumarate is hydrated through a reaction catalyzed by fumarase to make the intermediate malate e All the above are true f Only a and d are true 2 Please choose the True statement a Two molecules of CO2 are produced by TCA cycle for every acetyl CoA group that enters the cycle b The overall rate of catalysis in the TCA cycle is up regulated by high levels of ATP c The rate of the TCA cycle is influenced primarily through regulation of the enzyme malate dehydrogenase d Only a and b are true 3 The alpha ketoglutarate dehydrogenase enzyme complex requires several cofactors which include Coenzyme A NAD and FAD True False 4 Please choose the True statement regarding the use of TCA intermediates in other pathways a Oxaloacetate is used to produce nucleotides and some amino acids b Succinyl CoA is used in heme synthesis c Alpha ketoglutarate is used to produce amino acids and nucleotides d All the above are true e Only a and c are true 5 Mammals use acetyl CoA to make which of the following a Fatty acids steroids glucose and citrate b Fatty acids glucose citrate and ketone bodies c Fatty acids and citrate only d Fatty acids citrate ketone bodies and steroids 6 Ubiquinol is formed when ubiquinone accepts electrons from Complex III True False 7 If mitochondria were poisoned by addition of cyanide which of the following would be true a Complex III would be poisoned directly b Complex II would be poisoned directly c Complex I would be poisoned directly d Complex IV would be poisoned directly 8 Please choose the True statement a Fatty acids are synthesized in the mitochondrial matrix b Citrate is an inhibitor of fatty acid synthesis c Production of acetyl CoA is the first committed step in fatty acid synthesis d There are no true answers here 9 In order reactions of fatty acid synthesis are condensation oxidation hydration oxidation True False 10 Phosphorylase a which is used in glycogen metabolism is less active than phosphorylase b True False 11 Please choose the FALSE statement a De novo glycogen synthesis requires the primer glycogenin b Glucose 6 phosphate is released from glycogen branchpoints by the debranching enzyme c Glucagon binding to its receptor results in downstream activation of adenylyl cyclase d Glucagon is a hormone produced in the pancreas 1 Practice Exam IIID Derived from SS13 Exam IIIA 2 12 Please choose the true statement a Sphingolipids glycolipids phospholipids and cholesterol are all used as membrane lipids b Cholesterol is used as a synthetic precursor of NAD c Cholesterol esters have a Coenzyme A attached to the hydroxyl group d Biosynthesis of cholesterol occurs in the mitochondrion 13 Please choose the FALSE statement a Apolipoprotein B 48 is only made in the small intestine b In individuals homozygous for familial hypercholesterolemia too much LDL remains in the blood c LDL receptor synthesis is regulated by cholesterol levels such that high serum cholesterol results in an increase in LDL receptor synthesis d The lipids in LDL particles are mainly comprised of cholesterol and cholesterol esters 14 Please choose the true statement a VLDL are formed in the liver and the lipids contained in them are mostly triacylglycerols of dietary origin b HMG CoA reductase catalyzes the first committed step in cholesterol synthesis c Glucocorticosteroids are derivatives of arachadonic acid d Bile salts are made primarily from fatty acids and are used to emulsify dietary lipids 15 Please choose the true statement a Isopentenyl pyrophosphate is made when AMP levels in the cell are high b In a series of reactions during cholesterol synthesis 3 Molecules of ATP are used to make isopentenyl pyrophosphate c Squalene is a 10 carbon intermediate used in cholesterol synthesis d Oxidoreductase cyclizes lanosterol to make farnesyl pyrophosphate 16 Please choose the true statement a Acetyl CoA carboxylase catalyzes the committed step in fatty acid beta oxidation b NADPH reduces substrates in the reductive synthetic reactions of fatty acid beta oxidation c NADPH is produced in the non oxidative pentose phosphate pathway d Glutathione is important for reducing peroxides and other reactive oxygen species 17 Glucose 6 Phosphate dehydrogenase catalyzes the first committed step of the oxidative pentose phosphate pathway True False 18 Rapidly dividing cells that need ribose 5 P for nucleotide synthesis but not NADPH would use the oxidative pathway only and would not use the non oxidative pentose pathway True False 19 Deficiency of glucose 6 phosphate dehydrogenase is often sub clinical and becomes noticeable when a person has hemolytic anemia after oxidative challenge that can be a result of a Antibiotics b Anitmalarials c Infection d Eating certain foods like fava beans e All of the above 20 During oxidation of odd numbered fatty acids propionyl CoA is catabolized to succinyl CoA in a series of reactions that require Vitamin B12 True False Practice Exam IIID Derived from SS13 Exam IIIA 3 21 Isoprene units are used for the construction of all of the following EXCEPT a Membrane lipids in archaea b Sphingomyelin in eukaryotes c Cholesterol d Lipid anchors for membrane proteins 22 Please choose the true statement regarding phosphatidate Phosphatidate a is an intermediate in cholesterol synthesis b is an intermediate in sphingolipid synthesis c is an intermediate in the synthesis of triacylglycerol d All of the above are true 23 Dipalmitoyl phosphatidylcholine can be deficient in preterm infants and lead to respiratory distress True False 24 Please choose the FALSE answer regarding the response of liver cells to glucagon Glucagon promotes an a increase in the activity of glycogen synthase b increase in the activity of glycogen phosphorylase kinase c increase in the release of free glucose d increase in the intracellular concentrations of cAMP 25 Chylomicrons are produced in the liver and contain more triacylglycerol than cholesterol or cholesterol esters True False 26 Triacylglycerol must be catabolized to monoacylglycerol and two fatty acids to pass through the cell membrane and enter cells True False 27 In which of the following processes can glycerol be used as an
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