171 Biochemistry Exam 1 Questions with correct answers 2023/2024

171 Biochemistry Exam 1 Questions with correct answers 2023/ Biochemistry Exam 1 Questions with correct answers 2023/2024 Myoglobin >>What protein is used for storage? Myoglobin Hemoglobin Collagen Transferrin It's a covalent interaction >>What is NOT TRUE of antibodies with respect to protection? It is a covalent interaction It's a noncovalent interaction; hydrogen bonding Aspartic acid pKa=3.9 >>What is the amino acid that would dissociate a proton and make it ionizable in physiological pH? Aspartic acid pKa= 3.9 Histidine pKa= 6 Lysine Planar >>What is the configuration of a peptide bond? Peptide bonds need to be intact >>What do you have to have to make a protein denaturation reversible? Peptide bond needs to be intact Hydrogen bonds Disulfide Bonds Quaternary structure KEY WORD: SUBUNITS >>What is the spatial arrangement of amino acids and functional subunits? Tertiary structure Primary structure Secondary structure Quaternary structure Primary structure >>Which structure is predominantly responsible for a protein's 3D structure of amino acids and provides protein with function? Primary structure Secondary structure Tertiary structure Quaternary structure Insulation >>What is NOT considered one of the characteristics of amino acids? Support Protection Insulation High binding affinity and the amino group is . Protonated, Deprotonated Deprotonated, Protonated As pH decreases, the charge will become negative >>What is NOT TRUE of the pH and charge complementarity? Changes in charge affects protein function. As pH decreases, the charge will become negative As pH decreases, the charge will become more positive As pH increases, the charge will become more negative. Hydrophobic >>The interior of the protein is? None of these Hydrophobic Polar Glutamic acid >>What is the amino acid at the N-terminus, EGAK? Lysine Glutamic Acid Disulfide bonds >>What covalent interaction is the primary structure of proteins stabilized by? Hydrogen Bonding Ionic interactions Van der Waals Disulfide Bonds Phenylalanine, Tyrosine >>What 2 amino acids are considered aromatic? Hemoglobin >>What contains a quaternary protein structure? -1/km >>The x axis of a Lineweaver Burk plot is? • -1/km • Km • Vmax • The effect is facilitated by more oxygen binding >>The positive cooperativity of oxygen and hemoglobin is best described as • The effect is facilitated by more oxygen binding • Oxygen has no effect • Oxygen affinity decreases Methotrexate >>The reversible inhibitor in this group is? • Methotrexate • Cyanide • Organophosphates • Km is increased and Vmax is unchanged >>In Competitive inhibition, what happens to the Km and Vmax? • Km is increased and Vmax is unchanged • Km is decreased and Vmax is unchanged • Km and Vmax are both decreased • Km and Vmax are both increased • Km is unchanged Vmax is reduced >>In Noncompetitive inhibition, what happens to the Km and Vmax? • Km is unchanged Vmax is reduced • Vmax is increased and Km is unchanged • Km and Vmax are both decreased • Km and Vmax are both unchanged Would reduce the inhibitor action. >>Adding substrate in Competitive inhibition • Would reduce the inhibitor action. • Would enhance the inhibitor action. • Would have no effect on the inhibitor action. Inactive lacking a cofactor >>The definition of an apoenzyme is? • Inactive lacking a cofactor • Active lacking a cofactor • Inactive with a cofactor • Active with a cofactor The substrate concentration of ½ vmax >>Km is defined as • The substrate concentration of ½ vmax • ½ Vmax • Substrate concentration of Vmax • Substrate concentration Protein kinases >>The attachment of phosphoryl groups is by • Protein kinases • Protein phosphatases Zero kinetic order >>At high [S], what reaction order are you in? • Zero kinetic order • 1st Kinetic order • Subtrate has no effect on reaction order Irreversible inhibitor >>Organophosphates are considered what kind of inhibitor? • Irreversible inhibitor • Reversible inhibitor • Natural irreversible inhibitor • Competitive inhibitor • Reversible binds noncovalently and irreversible binds covalently >>The difference between reversible and irreversible is? • Reversible binds noncovalently and irreversible binds covalently • Reversible binds covalently and irreversible binds noncovalently • If a reaction will be endergonic, exergonic, or equilibrium >>Gibbs free energy best demonstrates • If a reaction will be endergonic, exergonic, or equilibrium • A negative entropy • A positive temperature Ligase >>The reaction A + B -> AB is best described as a? • Ligase • Lyase • Transferase • Hydrolase • Lowers the activation energy and facilitates the reaction to proceed >>The enzyme in a reaction? Galactose >>1. Which of the following is an example of a monosaccharide? a. Galactose b. Sucrose c. Lactose d. Maltose Maltose >>2. Which of the following is an example of a disaccharide? a. Glucose b. Fructose c. Galactose d. Maltose Homoglycan >>3. When all the monosaccharides in a polysaccharide are of the same type, such a type of a polysaccharide is called a? a. Glycogen b. Homoglycan c. Heteroglycan d. Oligosaccharide Starch >>4. In which of the following forms is glucose stored in plants? a. Glycogen b. Starch c. Dextrin d. Cellulose Glycogen >>5. In which of the following forms is glucose stored in the liver? a. Glycogen b. Starch c. Dextrin d. Cellulose Glycogen >>6. Which of the following is analogous to starch? a. Cellulose b. Glycogen c. Sucrose d. Chitin Hexokinase >>7. Which of the following enzyme catalyzes the first step of glycolysis? a. Hexokinase b. Pyruvate Kinase c. Glucokinase d. Phosphofructokinase I Fermentation >>8. The general term used for the anaerobic degradation of glucose to obtain energy is? a. Anabolism b. Oxidation c. Fermentation d. Metabolism Phosphofructokinase 1 (It is a regulatory enzyme and a major point of regulation) >>9. Whenever the cell's ATP supply is depleted, which of the following enzyme's activity is increased? a. Hexokinase b. Pyruvate kinase c. Glucokinase d. Phosphofructokinase I c. An aldose and a ketose (Glyceraldehyde 3-phosphate & dihydroxyacetone phosphate) >>10. Cleavage of Fructose 1,6-biphosphate yields a. Two aldoses b. Two ketoses c. An aldose and a ketose (Glyceraldehyde 3-phosphate & dihydroxyacetone phosphate) d. Only a ketose b. Oxidation of glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate >>11. The first step in the payoff phase of glycolysis is? a. Reduction of 1,3-biphosphoglycerate to glyceraldehyde 3-phosphate b. Oxidation of glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate c. Reversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3- phosphate d. Irreversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3- phosphate Hexokinase >>12. High concentration of glucose 6-phosphate is inhibitory to? a. Hexokinase b. Pyruvate kinase c. Glucokinase d. Phosphofructokinase I 3-phosphoglycerate >>13. The product formed in the first substrate level phosphorylation in glycolysis is? a. Pyruvate b. 3-phosphoglycerate c. 1,3-biphosphoglycerate d. 2-phosphoglycerate Glucose into pyruvate >>14. Glycolysis converts? a. Glucose into pyruvate b. Glucose into phosphoenolpyruvate c. Fructose into pyruvate d. Fructose into phosphoenolpyruvate Pyruvate dehydrogenase >>15. Enzyme involved in the pathway of synthesis of acetyl- CoA a. Hexokinase b. Pyruvate decarboxylase c. Pyruvate dehydrogenase d. Pyruvate kinase NAD+ >>16. In the reduction of pyruvate to lactate, which of the following is regenerated? a. H+ b. NADH c. NAD+ d. Na+ Gluconeogenesis >>17. When blood sugar levels fall, glycolysis is halted in liver to allow? a. Homeostasis b. Anaerobic respiration c. Aerobic respiration d. Gluconeogenesis It is stimulated by AMP and ADP >>18. Which of the following statements is true about PFK-1? a. It is stimulated by AMP and ADP b. It is stimulated by citrate and ATP c. It is inhibited by AMP and ADP d. It is stimulated by citrate and ADP a. From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a carbon source >>1. Which of the following statements is FALSE about gluconeogenesis? a. From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a carbon source. b. From red blood cells, lactate can be used as a carbon source c. From the hydrolysis of tri-acyl-glycerol, glycerol is converted to glucose in gluconeogenesis d. From muscle vigorous muscle activity, lactate can be used as a carbon source Malate dehydrogenase >>2. Oxaloacetate is reduced to malate by a. Pyruvate carboxylase b. Malate dehydrogenase c. Pyruvate kinase d. Phosphofructokinase-1 Pyruvate to glucose >>3. Gluconeogenesis involves conversion of a. Glucose to pyruvate b. Pyruvate to glucose c. Phosphoenolpyruvate to glucose d. Pyruvate to fructose a. 4 ATP, 2 GTP, and 2 NADH >>4. Formation of one molecule of glucose from pyruvate requires a. 4 ATP, 2 GTP, and 2 NADH b. 3 ATP, 2 GTP, and 2NADH c. 4 ATP, 1 GTP, 2 NADH d. 2 ATP, 2 GTP, and 2 NADH Alanine >>5. The main source of glucose carbons for glucose carbons for gluconeogenesis is a. Guanine b. Alanine c. Cysteine d. Threonine c. Glucose-6-phosphatase hydrolyzes glucose 6-phosphate to release glucose into the blood >>6. Which of the following statements about gluconeogenesis is correct? a. Pyruvate is first converted to phosphoenolpyruvate by phosphoenolpyruvate b. Fructose 1,6-biphosphatase converts fructose 1,6-biphosphate into fructose c. Glucose-6-phosphatase hydrolyzes glucose 6-phosphate to release glucose into the blood d. Glucose 6-phosphatase hydrolyzes glucose 6-phosphate and is found in liver and muscle True >>7. Anaerobic glycolysis can produce ATP at a much faster rate than aerobic oxidative phosphorylation. a. True b. False Aldol condensation >>8. Which of the following types of reaction does NOT occur in glycolysis? a. Isomerization b. Nucleophilic attack c. Aldol condensation d. Oxidation e. Dehydration Three strongly exergonic, nonequilibrium reactions >>9. Glycolysis is regulated primarily by: a. The availability of glucose-6-phosphate b. Three strongly endergonic, nonequilibrium reactions c. Three strongly exergonic, nonequilibrium reactions d. Allosteric effectors of pyruvate kinase e. Phosphorylation of phosphofructokinase e. ATP decreases the Km for its substrate fructose-6-phosphate >>10. Which of the following statements about regulation of phosphofructokinase is FALSE? a. AMP is an activator b. ADP is an activator c. Citrate is an inhibitor d. Fructose 2,6-biphosphate is an activator e. ATP decreases the Km for its substrate fructose-6-phosphate False >>11. All of the reactions of both glycolysis and gluconeogenesis occur in the cytosol. a. True b. False False >>12. The flux rate through the gluconeogenic pathway is directly proportional to the amount of carbohydrate in the diet. a. True b. False True >>13. Much of the regulation of gluconeogenesis is a result of the inhibition of glycolysis. a. True b. False Leucine >>14. Which of the following cannot be used as a precursor for gluconeogenesis? a. Glycerol b. Pyruvate c. Lactate d. Leucine e. Alanine Liver >>15. The primary gluconeogenic organ in animals is: a. Skeletal muscle b. Kidney medulla c. Kidney cortex d. Liver e. Heart muscle Lactate >>16. from muscle working anaerobically is released to blood and can be taken up by liver where it is converted to pyruvate by the enzyme lactate dehydrogenase. a. Lactate b. Pyruvate c. Glucose True >>Both glycolysis and gluconeogenesis are controlled by fructose-2,6-biphosphate in response to hormones. a. True b. False True >>Glycogen is a major energy source for skeletal muscle contraction a. True b. False Hormonal control >>Gluconeogenesis responds to which of the following? a. Hormonal control b. pH control c. Temperature control d. Blood control Gluconeogenesis >>When blood sugar levels fall, glycolysis is halted in liver to allow a. Homeostasis b. Anaerobic respiration c. Aerobic respiration d. Gluconeogenesis 7 >>How many steps are catalyzed by same enzymes in both glycolysis and gluconeogenesis? a. 6 b. 7 c. 8 d. 9 3 >>22. How many steps are catalyzed by different enzymes in glycolysis and gluconeogenesis? a. 2 b. 3 c. 4 d. 5 Stimulated by AMP and ADP >>23. Which of the following statements is true about PFK-1? a. It is stimulated by AMP and ADP b. It is stimulated by citrate and ATP c. It is inhibited by AMP and ADP d. It is stimulated by citrate and ADP Fructose 2,6-biphosphate >>24. Which of the following is a potent regulator of glycolysis and gluconeogenesis? a. Fructose 2,6-biphosphate b. Fructose 1,6-biphosphate c. Fructose 6-phosphate d. Glucose 1,6-biphosphate Muscle phosphorylase >>1. McArdle's disease is due to the deficiency of? a. Glucose-6-phosphatase b. Phosphofructokinase c. Liver phosphorylase d. Muscle phosphorylase All of the above >>2. Uridine diphosphate glucose (UDPG) is? a. Required for metabolism of galactose b. Required for synthesis of glucuronic acid c. A substrate for glycogen synthase d. All of the above c. Protein primer for glycogen synthesis >>3. Glycogenin is? a. An uncoupler of oxidative phosphorylation b. Polymer of glycogen molecules c. Protein primer for glycogen synthesis d. Intermediate in glycogen breakdown 6 and 11 >>4. The branching enzyme acts on the glycogen when the glycogen chain has been lengthened to between glucose units: a. 1 and 6 b. 2 and 7 c. 3 and 9 d. 6 and 11 Glucokinase >>5. Hexokinase has a high affinity for glucose than? a. Fructokinase b. Galactokinase c. Glucokinase d. All of the above Phosphorylase >>6. Glycogen is converted to glucose-1-phosphate by? a. UDPG transferase b. Branching enzyme c. Phosphorylase d. Phosphatase UDP glucose >>7. The tissues with the highest total glycogen content are? a. Glucuronic acid b. Pyruvic acid c. UDP glucose d. Sorbitol Pyruvate >>8. A regulator of the enzyme glycogen synthase is? a. Citric acid b. 2,3-biphosphoglycerate c. Pyruvate d. GTP UTP >>9. An essential component for converting glucose to glycogen in liver is? a. Lactic acid b. GTP c. CTP d. UTP Brain >>10. Glycogen is present in all body tissues except? a. Liver b. Brain c. Kidney d. Stomach Dextrin >>11. A polysaccharide which is often called animal starch is? a. Glycogen b. Starch c. Insulin d. Dextrin Cyclic AMP >>12. Glycogen synthetase activity is depressed by? a. Glucose b. Insulin c. Cyclic AMP d. Fructokinase Glycogen phosphorylase a >>13. One of the following enzymes does NOT change glycogen synthase a to b. a. Glycogen synthase kinases 3,4,5 b. Ca2+ calmodulin phosphorylase kinase c. Ca2+ calmodulin dependent protein kinase d. Glycogen phosphorylase a 300 >>14. The total glycogen content of the body is about grams. a. 100 b. 200 c. 300 d. 500 Glycogen >>15. During starvation, the 1st reserve nutrient to be depleted is? a. Glycogen b. Proteins c. Triglycerides d. Cholesterol Glycogenolysis >>16. The process of breakdown of glycogen to glucose in the liver and pyruvate and lactate in the muscle is known as? a. Glycogenesis b. Glycogenolysis c. Gluconeogenesis d. Cellular degradation UDP >>17. The pathway of glycogen biosynthesis involves a special nucleotide of glucose. In the reaction below, NuDP stands for NuDP Glucose + glycogen NuDP + glycogen+1 a. ADP b. GDP c. UDP d. CDP a. Amylo [14][16] transglucosidase >>18. In glycogenesis, a branch point in the molecule is established by the enzyme a. Amylo [14][16] transglucosidase b. Alpha 14 glucan transferase c. Amylo 16 glucosidase d. Glycogen synthase b. Glucose 6-phosphate glucose 1-phosphate >>19. In the synthesis of glycogen from glucose the reversible step is? a. Glucose glucose-6-phosphate b. Glucose 6-phosphate glucose 1-phosphate c. Glucose 1-phosphate UDP d. UDP glucose glycogen a. Glucose 6-phosphatase >>20. Von gierke's disease is characterized by the deficiency of? a. Glucose 6-phosphatase b. Alpha 14 glucosidase c. 16 glucosidase d. Liver phosphorylase b. Glucose 6-phosphate >>21. Allosteric activator of glycogen synthase is? a. Glucose b. Glucose 6-phosphate c. UTP d. Glucose 1-phosphate Mg2+ >>22. Action of glycogen synthase is inhibited by? a. Insulin b. Glucose c. Mg2+ d. Cyclic AMP Insulin >>23. The hormone activating the glycogen synthase activity is? a. Insulin b. Glucagon c. Epinephrine d. ACTH a. Alpha 1,4-glycosidic bonds >>24. Glycogen synthetase catalyzes the formation of? a. Alpha 1,4-glycosidic bonds b. Alpha 1,6-glycosidic bonds c. Both A & B d. None of the above Glucagon >>25. Glycogenolysis is increased by? a. Glucagon b. Insulin c. Epinephrine d. cAMP Glucagon >>26. hepatic glycogenolysis is increased by? a. Insulin b. Glucagon c. Epinephrine d. Glucocorticoids c. Glucose 1-phosphate >>27. Glycogen phosphorylase liberates the following from glycogen a. Glucose b. Glucose 6-phosphate c. Glucose 1-phosphate d. Maltose Muscles >>28. Glucose 1-phosphate liberated from glycogen cannot be converted into free glucose in? a. Liver b. Kidneys c. Muscles d. Brain Succinate dehydrogenase >>1. The only membrane bound enzyme in the citric acid cycle is a. Succinate dehydrogenase b. NADH dehydrogenase c. ATP synthase d. Acyl co-A dehydrogenase FMN >>2. Which of the following is the prosthetic group of NADH dehydrogenase? a. NADH b. FAD c. NADPH d. FMN a. Same as that normally produced by succinate >>3. If mitochondria were blocked at the site of NADH oxidation and were treated with succinate as substrate, what would the P:O ratio be? a. Same as that normally produced by succinate b. One more than normally produced by succinate c. One less than normally produced by succinate d. Zero c. Increased inorganic phosphate in the mitochondria >>4. If the oxidative phosphorylation was uncoupled in the mitochondria then there is a/an? a. Decreased concentration of ADP in the mitochondria b. Decreased oxidative rate c. Increased inorganic phosphate in the mitochondria d. Decreased production of heat a. Succinate oxidation remains normal >>5. If rotenone is added to the mitochondrial electron transport chain a. Succinate oxidation remains normal b. P:O ratio of NADH is reduced from 3:1 to 2:1 c. Oxidative phosphorylation is uncoupled at site 1 d. Rate of NADH oxidation is diminished to 2/3 of its initial value d. Substrate reacts to form a product containing a high energy bond >>6. Which of the following takes place in substrate level phosphorylation? a. Oxidation of one molecule of substrate is linked to synthesis of more than one ATP molecule b. High energy intermediate compounds cannot be isolated c. Only mitochondrial reactions participate in ATP formation d. Substrate reacts to form a product containing a high energy bond a. Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane >>7. Chemiosmotic hypothesis does not involve a. Only proton transport is strictly regulated, other positively charged ions can diffuse freely across the mitochondrial membrane b. ATPase activity is reversible c. Proton flow in to the mitochondria depends on the presence of ADP and Pi d. Electron transport by the respiratory chain pumps protons out of the mitochondria O2 >>8. Out of the following, the one having the highest redox potential is? a. Ubiquinone b. O2 c. FMN d. NAD ATP synthase >>9. ATP synthesis by chemiosmosis by? a. ATP dehydrogenase b. Gyrase c. ATP synthase d.Dehydrogenase Proton motive force >>10. The measure of potential energy stored as combination of proton and voltage gradients across membrane is termed as? a. Proton motive force b. Electron motive force c. Molecule motive force d. Ion motive force Acyl cartinine >>11. The transport of acyl co-A for oxidation using a shuttle involves formation of the intermediate a. Acyl coenzyme A b. 3 acetyl co-A c. Acyl cartinine d. None Mitochondrial matrix >>12. The acyl co-A formed in the cytosol is transported to a. Mitochondrial matrix b. Microsomes c. ER d. Remains in cytosol Are required to make ATP >>13. Membrane potential and proton gradient a. Cancel one another when uncouplers are present b. Reinforce one another when respiratory inhibitors are present c. Are sufficient, separately to make ATP from ADP + Pi d. Are required to make ATP Mitochondria >>14. Where does oxidative phosphorylation take place? a. Ribosomes b. Nucleus c. Mitochondria d. Cell membrane 60% >>15. What is the proportion of ATP produced by oxidative phosphorylation? a. 60% b. 70% c. 80% d. 90% NADH and FADH2 >>16. Products of glucose oxidation essential for oxidative phosphorylation are a. Pyruvate b. Acetyl co-A c. NADPH and ATP d. NADH and FADH2 Increase ATP production >>17. The effect of increased levels of hydrogen ions in the inter-membrane space of the mitochondria is a. Increase ATP production b. Decreased levels of oxidative phosphorylation c. Increased levels of water in inter-membrane space d. Decreased levels of chemiosmosis a. NAD-linked dehydrogenases >>1. In mitochondria, hydride ions are removed from substrates by? a. NAD-linked dehydrogenases b. NADP-linked dehydrogenases c. ATP synthase d. Succinate dehydrogenases 13 >>2. How many human mitochondrial proteins are encoded in the mitochondrial genome and synthesized within mitochondria? a. 11 b. 12 c. 13 d. 14 a. Absence of genetic recombination of mt-DNA >>3. Mitochondrial DNA is one of the best marker tools for population biologists and evolutionary biologists because a. Absence of genetic recombination of mt-DNA b. Mitochondrial genes are specific to mt-DNA c. It can be easily isolated d. It undergoes spontaneous mutation d. NADH and FADH2 >>4. Products of glucose oxidation essential for oxidative phosphorylation are a. Pyruvate b. Acetyl CoA c. NADPH and ATP d. NADH and FADH2 Inner mitochondrial membrane >>5. Enzymes catalyzing electron transport are present mainly in the a. Ribosomes b. Endoplasmic reticulum c. Lysosomes d. Inner mitochondrial membrane NADP >>6. Mitochondrial alpha-ketoglutarate dehydrogenase complex requires all the following to function except a. CoA b. FAD c. NAD d. NADP Mitochondria >>7. Enzymes responsible for ketone body formation are associated mainly with the a. Mitochondria b. Endoplasmic reticulum c. Nucleus d. Golgi apparatus Malate >>8. Mitochondrial membrane is freely permeable to a. Pyruvate b. Malate c. Oxaloacetate d. Fumarate d. Glucose 6-phosphate dehydrogenase >>9. A deficiency in which enzyme of the pentose phosphate pathway leads to hemolytic anemia and favism? a. Lactonase b. Transaldolase c. Transketolase d. Glucose 6-phosphate dehydrogenase Ribulose and NADPH >>10. In the pentose phosphate pathway, the major products are a. Ribulose and NADPH b. Ribulose and NADH c. Ribulose and NAD+ d. Ribulose and ATP c. The pathway supplies ribose 5-phosphate and NADPH in the quantities the cell requires >>11. Which of the following statements is correct about oxidative pentose phosphate pathway? a. It generates NADH b. It oxidizes NADPH to NADP+ c. The pathway supplies ribose 5-phosphate and NADPH in the quantities the cell requires d. Glucose 6-phosphatase catalyzes the rate limiting reaction of the pathway a. 3 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2 >>12. Oxidation of 3 molecules of glucose by pentose phosphate pathway results in the production of a. 3 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2 b. 4 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2 c. 4 molecules of pentose, 3 molecules of NADPH and 3 molecules of CO2 d. 3 molecules of pentose, 4 molecules of NADPH and 3 molecules of CO2 d. Supply pentose and NADPH >>13. The main function of the pentose phosphate pathway is to a. Supply NADP+ b. Supply NADH c. Supply energy d. Supply pentose and NADPH NADPH for reductive synthesis >>14. Pentose phosphate pathway is of significance because it generates a. NADPH for reductive synthesis b. Regenerates glucose 6-phosphate c. Generates fructose 6-phosphate d. Forms glyceraldehyde 3-phosphate NADP >>15. The hydrogen acceptor used in pentose phosphate pathway is a. NAD b. NADP c. FAD d. FMN Cytosol >>16. The enzymes of the pentose phosphate pathway are found in the a. Cytosol b. Mitochondria c. Nucleus d. Endoplasmic reticulum c. Glutathionic peroxidase >>17. The pentose phosphate pathway protects erythrocytes against hemolysis by assisting the enzyme: a. Superoxide dismutase b. Catalase c. Glutathionic peroxidase d. Cytochrome oxidase a. Glucose 6-phosphate dehydrogenase >>18. Hemolytic anemia is caused by the deficiency of certain enzymes of the pentose phosphate pathway, the principal enzyme involved is a. Glucose 6-phosphate dehydrogenase b. Aldolase c. Fructose 1,6-biphosphatase d. Phosphohexose isomerase Pentose phosphate pathway >>19. The main source of reducing equivalents (NADPH) for lipogenesis is a. Pentose phosphate pathway b. Citric acid cycle c. Glycolysis d. Glycogenolysis d. Reduce oxidizing agents such as H2O2 >>20. Reduced glutathione functions in red blood cells to a. Produce NADPH b. Reduce methemoglobin to hemoglobin c. Produce NADH d. Reduce oxidizing agents such as H2O2 Tripeptide >>21. Glutathione is a a. Dipeptide b. Tripeptide c. Polypeptide d. None of the above Adenine >>1. Identify the purine base of nucleic acids in the following: a. Cytosine b. Thymine c. Uracil d. Adenine c. The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage >>2. Which of the following statements is true? a. Sugar component of a nucleotide is ribose b. Sugar component of a nucleotide is deoxyribose c. The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage d. The sugar molecule of the nucleotide is in L-configuration A base + a sugar >>3. What is the composition of a nucleoside? a. A sugar + a phosphate b. A base + a sugar c. A base + a phosphate d. A base + a sugar + a phosphate A base + a sugar + a phosphate >>4. What is the composition of a nucleotide? a. A sugar + a phosphate b. A base + a sugar c. A base + a phosphate d. A base + a sugar + a phosphate Phosphodiester bond >>5. Group of adjacent nucleotides are joined by? a. Phosphodiester bond b. Peptide bond c. Ionic bond d. Covalent bond a. 5' phosphate group of one nucleotide unit is joined to the 3' hydroxyl group to the next nucleotide >>6. Which of the following is true about phosphodiester linkage? a. 5' phosphate group of one nucleotide unit is joined to the 3' hydroxyl group to the next nucleotide b. 3' phosphate group of one nucleotide unit is joined to the 5' hydroxyl group to the next nucleotide c. 5' phosphate group of one nucleotide unit is joined to the 5' hydroxyl group to the next nucleotide d. 3' phosphate group of one nucleotide unit is joined to the 3' hydroxyl group to the next nucleotide GMP and AMP >>9. An allosteric inhibitor of PRPP glutamyl amido transferase is a. AMP b. ADP c. All of these d. GMP AND AMP c. Aspartate, glutamine and glycine >>15. The nitrogen atoms for de novo synthesis of purine nucleotides are provided by a. Aspartate and glutamate b. Aspartate and glycine c. Aspartate, glutamine and glycine d. Aspartate, glutamate, and glycine d. One nitrogen and two carbon atoms >>16. For de novo synthesis of purine nucleotides, glycine provides a. One nitrogen atom b. One nitrogen and one carbon atom c. Two carbon atoms d. One nitrogen and two carbon atoms Both >>17. 5-phosphoribosyl-1-pyrophosphate is required for the synthesis of a. Purine nucleotides b. Pyrimidine nucleotides c. Both d. None of these d. Adenine, guanine, and hypoxanthine >>18. Free purine bases which can be salvaged are a. Adenine and guanine b. Adenine and hypoxanthine c. Guanine and hypoxanthine d. Adenine, guanine, and hypoxanthine Uric acid >>21. The end product of purine catabolism in man is a. Inosine b. Hypoxanthine c. Xanthine d. Uric acid Aspartate >>1. Which of the following is an important precursor in the pyrimidine pathway? a. Glycine b. Aspartate c. Glutamine d. Leucine a. Thymidylate synthase >>4. Conversion of dUMP to dTMP is catalyzed by? a. Thymidylate synthase b. Dihydrofolate reductase c. Dihydroorotase d. Cytidylate synthase Gout >>5. A synthetic nucleotide analogue, 4-hydroxypyrazolopyrimidine is used in the treatment of? a. Acute nephritis b. Gout c. Cystic fibrosis d. Multiple myeloma Purine >>6. Gout is a metabolic disorder of catabolism of? a. Pyrimidine b. Purine c. Alanine d. Phenylalanine Uric acid >>7. Gout is characterized by increased plasma levels of? a. Urea b. Uric acid c. Creatine d. Creatinine b. Thymidylate synthetase >>8. Conversion of deoxyuridine monophosphate to thymidine monophosphate is catalyzed by the enzyme? a. Ribonucleotide reductase b. Thymidylate synthetase c. CTP synthetase d. Orotidylic acid decarboxylase d. Lesch-Nyhan syndrome >>9. Complete absence of hypoxanthine guanine phospharibosyl transferase causes? a. Primary gout b. Immunodeficiency c. Uric acid stones d. Lesch-Nyhan syndrome c. Carbamoyl phosphate >>12. Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of? a. Carbamoyl aspartate b. Orotate c. Carbamoyl phosphate d. Dihydroorotate d. Dihydro-orotate dehydrogenase >>1. All the enzymes required for de novo synthesis of pyrimidine nucleotides are cytosolic except? a. Carbamoyl phosphate synthetase b. Aspartate transcarbamoylase c. Dihydro-orotase d. Dihydro-orotate dehydrogenase c. The presence of a double bond in the hydrocarbon chain >>1. Unsaturated fatty acids and saturated acids are distinguished based on: a. The length of the hydrocarbon chain b. The number of carbons in the fatty acid chain c. The presence of a double bond in the hydrocarbon chain d. The lack of a hydrophilic phosphate group None of the above >>2. Which of the following is NOT a function of fatty acids: a. Immune regulation b. Cell membrane c. Gene expression d. B and C only e. None of the above Biotin >>3. Conversion of acetyl CoA to malonyl coA requires which of the following? a. NADPH b. H2O c. Folic acid d. Biotin Liver >>4. Where does triacylglycerol form? a. Liver b. Kidneys c. Adipose tissue d. Heart Carbohydrates >>5. Glucose will be converted into fatty acids if the diet has excess of? a. Carbohydrates b. Proteins c. Fat d. Vitamins c. Transformation of acetyl coA to pyruvate >>6. Fatty acids cannot be converted into carbohydrates in the body as the following reaction is not possible. a. Conversion of glucose 6-phosphate into glucose b. Fructose 1,6-biphosphate to fructose 6-phosphate c. Transformation of acetyl coA to pyruvate d. Formation of acetyl coA from fatty acids Combined with albumin >>7. Free fatty acids are transported in the blood a. Combined with albumin b. Combined with fatty acid binding protein c. Combined with beta-lipoprotein d. In unbound free salts Cytosol >>8. Long chain fatty acids are first activated to acetyl coA in a. Cytosol b. Microsomes c. Nucleus d. Mitochondria Cytosol >>9. De novo synthesis of fatty acids occurs in a. Cytosol b. Mitochondria c. Microsomes d. All of these ATP >>10. De novo synthesis of fatty acids requires all of the following except? a. Biotin b. NADH c. Panthothenic acid d. ATP All of these >>11. Which of the following can be oxidized by beta-oxidation pathway? a. Saturated fatty acids b. Monosaturated fatty acids c. Polyunsaturated fatty acids d. All of these c. It is required for transport of short chain fatty acids into mitochondria >>12. All of the following statements about carnitine are true except? a. It can be synthesized in the human body b. It can be synthesized from methionine and lysine c. It is required for transport of short chain fatty acids into mitochondria d. Its deficiency can occur due to hemodialysis