16. Test 3_3.04.2013 Test 088 E) Is preceded by synthesis of a hig...

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16. Test 3_3.04.2013 Test 088 E) Is preceded by synthesis of a high energy intermediate A) + 46) 2 During NADPH the biosynthesis 1 ATP of saturated fatty acids, the addition of every two-carbon unit requires: B) 2 NADH + 1 ATP C) I NADPH + 1 FADH2 + 1 ATP D) 1 NADH + 1 FADH2 + 1 ATP E) 1 NADPH + 1 ATP 47) In muscle cells, high [Ca²"]: A) Stimulates glycogen synthesis B) Activates gluconeogenesis C) Activates glycogen degradation D) Inhibits glycolysis E) Inhibits the Krebs cycle 48) Classical galactosemia is caused by inherited deficieney of galactose 1-phosphate uridylyItransferase activity. The consequences of this defect are all EXCEPT: A) Accumulation of alactose-1-phosphate and free galactose in tissues B) The inability to produce UDP-galactose from UDP-glucose C) Depletion of inorganic phosphate levels in the liver which can interfere with normal cell function D) Conversion of galactose to galactitol, leading to the increased risk of cataracts E) The inability to convert dietary galactose to glucose 49) Electrons from cytosolic NADH produced in glycolysis may be transported to mitochondrial NAD* through which of the following compounds: A) malate B) lactate C) oxaloacetate D) glutamate E) pyruvate 50) (1) Lactose is hydrolyzed in the gastrointestinal tract by a brush-border disaccharidase; (2) The major transport system for glucose to the intestinal epithelial cells is a secondary active transport; (3) structure of - correct is(are): starch (especially amylopectin) resembles that of glycogen, and both can be hydrolyzed by pancreatic amylase A) Only 1 and 2 B) Only 1 and 3 C) All D) Only 2 E) Only 1 A) The apoB-100 protein cannot be synthesized (ACAT) is deficient B) Defects in the LDL receptor acyl transferase gene are responsible for steroids the elevated blood level of LDL C) D) HMG-CoA reductase is not feedback inhibited by elevated 39) E) Which of the compounds presented in FIGURE 2 are classified as "high energy compounds": The HDL fraction of blood cholesterol is markedly A) All except 5 B) All C) Only 1. 2 and 4 D) Only I and 2 E) Only 1. 2 and 3 40) Compound No 3 in FIGURE 1 CAN NOT be converted in a single step (reaction) into: A) a-ketoglutarate B) citrate C) phosphoenopyruvate D) aspartate E) malate A) 41) One isoform of the enzyme catalyzing this reaction - COX-1 is constitutively expressed in many tissues, while Choose the INCORRECT statement concerning the reaction shown in Figure 5: COX-2 is induced in the inflammatory state. B) Inhibitor x could be an anti-inflammatory steroid C) The dietary precursor of the substrate is the essential fatty acid, linoleic acid; D) Inhibitor x could be a nonsteroidal anti-inflammatory drug (NSAID) E) Product of the reaction can be converted to a variety of prostaglandins and tromboxanes A) Different metabolic fates of glucose released and the allosteric effect of AMP on glycogen phopshorylase b 42) The difference in glycogen degradation in liver and muscle cell concerns: B) None of the answers is correct C) Different effect of phosphorylation of the key enzyme on its activity D) The key reactions that brake down glycosidic bonds are: phosphorolysis in muscle cells and hydrolysis in hepatocytes E) Different effect of the increased cAMP levels on the rate of the process 43) The disaccharide lactose is composed of: A) glucose and mannose B) glucose and galactose C) glucose and fructose D) two molecules of glucose E) galactose and mannose 44) Choose the correct statement concerning the reaction shown in FIGURE 3: A) Product of this reaction is a substrate for the Complex II of the respiratory chain B) It can serve as a source of ATP under anaerobic conditions C) It takes place in hepatocytes only D) It takes place in the cytoplasm E) x is FAD 45) The production of ATP in glycolysis: A) Takes place in four different reactions B) Is a major ATP source for most cells C) Requires formation of acetyl-CoA D) Gives rise to the net production of four ATP per each glucose C) Lactate, alanine and glycerol can serve as substrates D) ATP is not required E) It releases glucose from glycogen stores A) 1 molecule of 2-monoacylglycerol and 2 molecules of acyl-CoA are necessary to resynthesize 1 molecule of 24) Choose the INCORRECT: B) Chylomicron remnants are taken up by the liver, this involves interaction of the apoE protein with a specific triacylglycerol in intestinal epithelial cells C) Medium chain fatty acids absorbed from the intestine into the blood are transported by plasma albumin receptor D) Lipid-soluble vitamins absorbed in the intestine are transported by chylomicrons E) B-100 is a major structural protein of chylomicrons 25) Lipoprotein lipase: A) is a lysosomal enzyme B) is the main enzyme that breaks down dietary fats in the human digestive system C) is activated when the body needs to mobilize energy stores D) is an intracellular lipase E) is attached to the luminal surface of endothelial cells in capillaries 26) In some countries newborn screening exams include testing for an inherited disease - methylmalonic acidemia. The disease can lead to progressive encephalopathy and death when untreated, and is caused by deficiency of the enzyme involved in: A) metabolism of leucine B) degradation of aromatic amino acids vitamin B12 dependent conversion of methylmalonyl-CoA to succinyl-CoA D) degradation of sphingolipids E) carboxylation of propionyl-CoA 27) The first step of ß oxidation is a(n) A) NAD' -dependent oxidation of acyl-CoA: B) biotin C) NADP D) FAD E) FMN A) thiamine pyrophosphate 28) Which coenzyme is NOT required for the activity of the pyruvate dehydrogenase complex: B) flavin adenine dinucleotide C) lipoic acid D) biotin E) coenzyme A 29) Which of the redox pairs has the most POSITIVE reduction potential: A) FAD/FADH2 B) Oxidized coenzyme Q/reduced coenzyme Q C) IAD'/NADH D) Oxidized cytochrome c/reduced cytochrome e E) OyHo 30) Free fatty acids released from adipose are transported in blood: A) as complexes with plasma albumins B) by HDL particles C) by chylomicrons D) by LDL particles E) by VLDL particles 31) Acetyl-CoA can serve as a substrate for all of the following reactions EXCEPT: A) Biotin and ATP dependent carboxylation to pyruvate B) Condensation with acetyl-CoA to form acetoacetyl-CoA C) The ATP dependent carboxylation to form malonyl-CoA D) Condensation with oxaloacetate to form citrate E) Condensation with acetoacetyl-CoA to form 3-hydroxy-3-methyl glutaryl-CoA (HMGCoA) 32) Glucokinase and hexokinase are isoenzymes. Choose the correct description of differences/similarities between them: A) Glucokinase is a constitutive enzyme, while hexokinase is an inducible one - its activity changes in response to hormonal signals B) Glucokinase has lower affinity for glucose than hexokinase C) The activity of both is allosterically regulated by feedback inhibition by the product D) Both catalyze reversible reactions E) Both are found in almost all types of cells 33) A reaction that DOES NOT take place in the pentose phosphate pathway is: A) Dephosphorylation B) Decarboxylation C) Two-carbon transfer D) Oxidation/reduction E) Three-carbon transfer 34) The beta-oxidation of fatty acids: A) Is inhibited by increased level of cytoplasmic malonyl-CoA B) Requires both mitochondrial and cytoplasmic enzymes C) Can proceed both under aerobic and anaerobic conditions D) Produces NADPH for various biosyntheses E) Degrades acyl-CoA into two-carbon units, leading to the reduction of 2 NAD' per each unit released 35) What is the approximate yield of ATP (from ADP) when one molecule of the direct product of muscle glycogen phosphorylase is converted to lactic acid under anaerobic conditions: A) B)4 C)3 D) 1 E): 2 36) Which of the following reactions generate CO2: (1) oxaloacetate^ phosphoenolpyruvate; (2) isocitrate a-ketoglutarate; (3) a-ketoglutarate succinyl-CoA; (4) 6-phosphogluconate>ribulose-5-phosphate: A) All B) Only 1 and 4 C) All except 2 D) Only 3 and 4 E) All except 1 37) The activity of pyruvate dehydrogenase complex (PDH) decreases: A) as the concentration of acetyl CoA decreases B) as the concentration of AMP increases C) as the concentration of pyruvate increases D) when the dephospho-enzyme is converted to its phosphorylated form E) as the concentration of NAD' increases 38) In familial hypercholesterolemia: coo- FIGURE 1 1 COO C-O COO COO" o o 1 - C CH CH2 HO C-H C=O Il 1 - C=0 HC CH2 CH2 CH2 I I CH3 COO COO COO" COO 1 2 3 4 5 O FIGURE 2 NH N G o of o OE 11 NH2 o o ago N HO P O P O N 1 o O : o C o P o HCOH OHOH CH2 o CH,OPO," 1 2 3 CH2OPO}- o o CH3 H HO S CoA H OH OH H 4 5 FIGURE 4 FIGURE 3 COO O coo' CH2 o CH3 + H-C" II II I CH2 ÇH2 ÇH2 C-0-P-0° C=O I 1 I I - - C=0 H-C-OH - C-S-CoA CH2 COO o COO I I i COO CH2OPO}- o X Y COO 1 2 3 4 FIGURE 5 FIGURE 6 coo' 202 R x o. OH coo" HOOM OH 1 OOH 2 FIGURE 7 1 a CH2OH CH2 CH2OH ***** a OH 1. o o OH OH II OH CH3-CH-CH,-COO- CH3-C-CH--COO- OH OH OH

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24. E
25. E
26. C
27. D...

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