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BBL EXAM STUDY GUIDE
Starting with glyceraldehyde 3-phosphate and synthesizing one molecule of pyruvate, the net yield of ATP and NADH would be which of the following? A. 1 ATP, 4 NADH B. 2 ATP, 1 NADH C. 1 ATP, 2 NADH D. 2 ATP, 2 NADH E. 1 ATP, 1 NADH - Answer B. 2 ATP, 1 NADH Which of the following compounds does NOT contain a high-energy bond? A. Phosphoenolypyruvate B. ATP C. Glucose 6-phosphate D. Acetyl CoA E. UDP-glucose - Answer C. Glucose 6-phosphate Sodium fluoride inhibits glycolysis by affecting A. hexokinase B. phosphatase C. amylase D. enolase E. phosphorylase - Answer D. enolase Which of the following liver enzymes, absent from other tissues, gives the liver an advantage over other cells in taking up glucose after a meal? A. Aldolase B. Hexokinase C. Glucokinase D. Enolase E. Glucose 6-phosphatase - Answer C. Glucokinase
All of these compounds are intermediates of glycolysis except A. Glyceraldehyde 3-phosphate B. Glycerol 6-phosphate C. Fructose 6-phosphate D. Fructose 1,6-bisphosphate E. Glucose 6-phosphate - Answer B. Glycerol 6-phosphate Anaerobic metabolism refers to the generation of ATP A. without the use of oxygen B. by the conversion of pyruvate to lactate C. without the use of glycogen D. without the involvement of ADP E. in the absence of available oxygen - Answer A. without the use of oxygen
- The most rapid method to re-synthesize ATP during exercise is through: A. tricarboxylic acid cycle (Krebs' cycle) B. glycogenolysis C. phosphocreatine breakdown D. gluconeogenesis E. glycolysis - Answer C. phosphocreatine breakdown Which of the following enzymes is essentially absent from normal mammalian muscle? A. Glucokinase B. Phosphorylase C. Glucose-6-phosphatase D. Glucose-6-phosphate isomerase E. Glucose-6-phosphate dehydrogenase - Answer C. Glucose-6-phosphatase Which of the following is glucogenic amino acid? A. Leucine B. Isoleucine
- Fructose-2, 6-biphosphate is formed by the action of A. Phosphofructokinase- B. Phosphofructokinase- C. Fructose biphosphate isomerase D. Fructose-1, 6-biphosphatase E. Fructose-2, 3-biphosphate - Answer B. Phosphofructokinase- Which of the following is unique to α-keto acid dehydrogenase complexes? A. Lipoic acid B. GDP C. H2O D. NAD+ E. FAD - Answer A. Lipoic acid Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It contains Fe-S centers B. It is inhibited by NADH C. It is regulated by a kinase D. It contains bound FAD E. It is embedded in the inner mitochondrial membrane - Answer E. It is embedded in the inner mitochondrial membrane How many moles of ATP are generated by the complete aerobic oxidation of 1 mole of glucose to 6 moles of CO2? A. 30 to 32 B. 10 to 12 C. 18 to 22 D. 60 to 64 E. 2 to 4 - Answer A. 30 to 32 The TCA cycle is an oxidative pathway requiring oxygen for operation. The enzyme which consumes oxygen during the operation of the cycle is
A. Isocitrate dehydrogenase B. Alpha-ketoglutarate dehydrogenase C. Aconitase D. Cytochrome c oxidase E. None of the above - Answer E. None of the above The tricarboxylic acid cycle is initiated by the condensation of which of the following pair of molecules? A. Acetyl coenzyme A and oxalosuccinate B. NAD+ and oxaloacetate C. Pyruvate and malate D. Acetyl coenzyme A and oxaloacetate E. NAD+ and oxalosuccinate - Answer Acetyl coenzyme A and oxaloacetate Enzymes concerned with the citric acid cycle are found in the A. nucleus B. ribosomes C. mitochondria D. nonparticulate cytoplasm E. none of the above - Answer C. mitochondria
- Which of the following intermediary metabolites of the TCA cycle is formed, in part, by the removal of a CO2 molecule? A. Lactate B. Citrate C. Malate D. α-ketoglutarate E. Oxaloacetate - Answer D. α-ketoglutarate Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It contains Fe-S centers
C. The formation of thioesters in the matrix D. A conformational change in the inner membrane E. None of the above - Answer B. An H+ gradient across the inner membrane Aerobic resynthesis of ATP occurs A. in the cytosol B. in the sarcoplasmic reticulum C. in the mitochondria in a process called glycogenolysis D. only in Type I muscle fibres E. in the mitochondria in a process called oxidative phosphorylation - Answer E. in the mitochondria in a process called oxidative phosphorylation
- Substrate-level phosphorylation differs from oxidative phosphorylation in that: A. oxidative phosphorylation only occurs in the cytosol B. substrate-level phosphorylation involves the transfer of electrons C. substrate-level phosphorylation only occurs in the cytosol D. oxidative phosphorylation involves the transfer of electrons E. GTP is always involved in substrate-level phosphorylation - Answer D. oxidative phosphorylation involves the transfer of electrons When glycogen is degraded, glucose 1 phosphate is formed. Glucose 1 phosphate can then be isomerized to glucose 6 phosphate. Starting with glucose 1 phosphate and ending with two molecules of pyruvate, what is the net yield of glycolysis in terms of ATP and NADH formed? A. 3 ATP, 2 NADH B. 2 ATP, 2 NADH C. 2 ATP, 1 NADH D. 2 ATP, 3 NADH E. 1 ATP, 3 NADH - Answer A. 3 ATP, 2 NADH Muscle glycogen does not yield blood glucose directly but liver glycogen does because A. hexokinase is not present in liver B. muscle does not contain phosphoglucomutase
C. glucose-6-phosphatase is not present in muscle D. muscle glycogen differs in structure from liver glycogen E. muscle cells are impermeable to glucose - Answer C. glucose-6-phosphatase is not present in muscle Epinephrine causes an elevation in cAMP levels in muscle cells, which in turn activate A. ATPase B. glycogen synthetase C. glycogen phosphorylase phosphatase D. glycogen phosphorylase E. adenyl cyclase - Answer D. glycogen phosphorylase Which of the following generates free glucose during the enzymatic breakdown of glycogen in skeletal muscle? A. phosphorylase B. debranching enzyme C. amylase D. glucose-6-phosphatase E. None of the above - Answer B. debranching enzyme The enzymes of the pentose phosphate pathway are found in the A. Cellular membrane B. Cytosol C. Nucleus D. Mitochondria E. Endoplasmic reticulum - Answer B. Cytosol One of the principal functions of the pentose phosphate pathway is to A. maintain the ratio of NADPH/NADP+ at a very high level in the cytosol B. maintain the ratio of NAD+/NADH at a very high level in the cytosol C. metabolize glucose completely to carbon dioxide D. metabolize galactose
C. Mitochondrial matrix (i.e., inside the mitochondria) D. Space between inner and outer mitochondrial membranes - Answer D. Space between inner and outer mitochondrial membranes
What metabolic pathway(s) make ATP from the electron carriers that come off of the fatty acid oxidation pathway? A. glycolysis, pentose phostphate, TCA B. oxidative phosphorylation only C. pentose phosphate, TCA, oxidative phosphorylation D. TCA, oxidative phosphorylation - Answer B. oxidative phosphorylation only
With regard to the ketogenesis process, which of the following is correct? A. In the liver, acetoacetyl-CoA is made from 2 acetyl CoA molecules B. The liver can use ketone bodies as energy sources C. At the target tissues, ketone bodies must eventually be converted to acetoacetate D. All the above - Answer C. At the target tissues, ketone bodies must eventually be converted to acetoacetate
The inner mitochondrial membrane can transport A. acyl-carnitine B. acetyl-CoA C. fatty acids D. malonyl-CoA - Answer A. acyl-carnitine
- Which statement about beta-oxidation and synthesis of fatty acids is NOT correct? A. Both synthesis and beta-oxidation occur in steps of 2 carbon fragments. B. Breakdown of fatty acids creates NADH that can feed into the electron transport chain. C. Beta-oxidation is simply the direct reversal of all the same steps that occur in
synthesis. D. Beta-oxidation involves a number of reduction reactions. - Answer D. Beta-oxidation involves a number of reduction reactions.
Which enzyme controls the committed step in cholesterol biosynthesis? A. HMG CoA reductase B. Fatty acid synthetase C. Acetyl CoA carboxylase D. Carnitine acyl transferase - Answer A. HMG CoA reductase
The physiologically active form of vitamin D produced in the kidney is: A. 7-dehydrocholesterol B. 25-hydroxycholecalciferol C. 1,25-dihydroxycholecalciferol D. Cholecalciferol - Answer C. 1,25-dihydroxycholecalciferol
Which lipoprotein complexes handle TAG transport in the bloodstream? A. LDL, HDL B. VLDL, chylomicrons C. chylomicrons, HDL D. LDL, VLDL - Answer B. VLDL, chylomicrons
What role does HDL play in cardiovascular disease? A. Major contributor to plaque deposits B. Can scavenge deposited cholesterol from vessel walls C. Reduces inflammatory response to vessel lumen damage D. All of the above - Answer B. Can scavenge deposited cholesterol from vessel walls
pathways
When glutamate donates an amine group to pyruvate, which amino acid is formed? A. Serine B. Proline C. Alanine D. Aspartate - Answer C. Alanine
Both serine and threonine are directly deaminated to A. Alpha ketoglutarate B. Oxaloacetate C. Acetyl-CoA D. Pyruvate - Answer D. Pyruvate
A Schiff's base mechanism takes place during the transaminase reaction. Which of the following statements correctly describes this mechanism? A. A lysine residue becomes protonated in the active site, which causes the first amino acid to directly aminate the first keto acid to the new amino acid B. Pryidoxal phosphate in the active site of the transaminase is aminated forming pyridoxamine from the first amino acid, then the first keto acid is released C. Biotin is aminated in the active site of the transaminase by the incoming first amino acid to produce the first keto acid released as a product D. An active site lysine residue is aminated by the incoming amino acid forming the first keto acid, which is then released as a product - Answer B. Pryidoxal phosphate in the active site of the transaminase is aminated forming pyridoxamine from the first amino acid, then the first keto acid is released
The transamination of oxaloacetate forms A. Glutamate B. Asparagine
C. Threonine D. Aspartate - Answer D. Aspartate
The serine-glycine complex plays a role in A. Adenylation of methionine to S-adenosyl-methionine B. Methylation of macromolecules by S-adenosyl-methionine C. Remethylation of MTHF for the remethylation of homocysteine to methionine D. Formation of cysteine through transcultural ion pathway - Answer C. Remethylation of MTHF for the remethylation of homocysteine to methionine
- The product of S-adenosyl-methionine methylation is S-adenosyl -homocysteine, which is then de-adenylated. How is the cleaved adenosine utilized? A. Utilized to re-adenylation of methionine B. Adenosine is excreted C. Purine salvage pathway D. Recycled to ATP - Answer C. Purine salvage pathway
