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BMD 322 Name............................................. EXAM #1-1 2-1-
- Most metabolic processes are controlled by all of the following EXCEPT :
A. Covalent modification of specific enzymes B. Allostery C. Formation of multi-enzymatic complexes D. Regulation of transcription of specific genes E. Reversible binding and release of prosthetic groups to the active site
- The Km of an enzyme for its substrate is usually:
A. Around the intracellular concentration of the substrate B. Around the intracellular concentration of the enzyme C. Far below the intracellular concentration of the substrate D. Far below the intracellular concentration of the enzyme E. There is no relationship between intracellular substrate concentration and Km value
- What kinds of enzymes may have pyridoxal phosphate as a prosthetic group?
A. Oxidoreductases B. Transferases C. Hydrolases D. Lyases E. Isomerases
- Co-substrates:
A. Are part of the active site B. Remain tightly bound to an enzyme. C. Are recycled/reused by other enzymes D. Are inorganic ions E. Are continuously oxidized as a source of energy
- Loosely-bound metals required in chemical reactions are known as:
A. Coenzymes B. Cofactors C. Activators D. Metabolite cofactors E. Repressors
- Alcoholics may develop niacin deficiency. What kinds of enzymes would be affected by this syndrome?
A. Oxidoreductases B. Transferases C. Hydrolases D. Lyases E. Isomerases
- Which of the following vitamins is actually synthesized in the body?
A. A B. B complex C. C D. D E. E
- What is an anomeric carbon in a sugar?
A. The farthest chiral carbon from the carbonyl group B. The carbonyl group after it is converted into a hemiacetal C. The last carbon in the chain D. A term used in sugar chemistry to define any chiral carbon E. The carbon that determines whether a sugar is D- or L-
- Which of the following prosthetic groups does not contain adenine in its structure?
A. NAD B. NADP C. FAD D. FMN E. Coenzyme Q
- Which of the following cytochrome-types has the same heme structure found in hemoglobin?
A. Cytochrome a B. Cytochrome b C. Cytochrome c D. All of the above E. None of the above
- Eggs contain a protein called avidin which binds biotin tightly. Thus, excessive intake of raw eggs may cause a rare biotin deficiency. Which of the following enzymes will be affected in these patients?
A. Dehydrogenases B. Aminotransferases (Transaminases) C. Decarboxylases D. Carboxylases E. None of the above
- Which of the following compounds IS NOT a polysaccharide?
A. Chitin B. Glycogen C. Maltose D. Amylose
- Phospholipase ___ acts at the point indicated by the arrow:
A. A 1 B. A 2 C. C Figure D. D E. None of the above
- The main difference between gangliosides and cerebrosides is:
A. Gangliosides contain phosphate B. Only cerebrosides contain sphingosine C. Gangliosides contain branched polysaccharides D. Gangliosides usually contain a single galactosamine E. Cerebrosides contain phosphate
- A typical biological membrane contains:
A. Only lipids B. Only proteins C. About 60 % proteins and 40 % lipids D. About 90% lipids E. About 90% proteins
- Above the phase transition temperature:
A. The membrane becomes thinner B. There is less rotation around -C-C- bonds C. Lateral diffusion increases D. A and B are correct E. A and C are correct
- All of the following alcohols may be esterified with phosphate in glycerophospholipids EXCEPT :
A. Serine B. Inositol C. Cholesterol D. Choline E. Ethanolamine
- All of the following are characteristics of a phospholipid bilayer EXCEPT :
A. The lipid composition in both sides of the bilayer is usually different B. Lipids are free to move across the membrane C. The lateral diffusion of many membrane proteins is not restricted D. Integral protein are located across the membrane. E. Membrane glycoproteins face the inner side of the cell membrane
TRUE / FALSE
- Free glucose is always in the α configuration.
- Hyaluronic acid is an example of an acidic monosaccharide
- Lysozyme is a β glycosidase
- A molecule of glycogen has only one non-reducing end
- Saturated fatty acids decrease membrane fluidity
ESSAYS:
- Explain which is the biochemical principle behind new experimental anti-cancer drugs that inhibit heparanase.
- What is the effect of an allosteric modulator on the Km of an enzyme for its substrate?
- Describe three differences/similarities between phosphoglycerides and triacylglycerides.
- Explain the meaning of the prefixes AD-A and AL-A and the suffixes Apyranose@ and Afuranose@ in sugars (4 pts).
- Processes mediated by Gq proteins involve all of the following EXCEPT :
A. Phosphatidyl inositol B. Phospholipase C C. Ca + D. Protein kinase C E. cAMP
- Fructose entry in the glycolyitic pathway bypasses all the following points of regulation EXCEPT :
A. Hexokinase B. Glucokinase C. PFK- D. PFK- E. Pyruvate kinase
- Which of the following is a common intermediate in both glycogen synthesis and galactose metabolism?
A. Fructose 1,6-bisphosphate B. Fructose 2,6-bisphosphate C. UDPG D. Maltose E. Fructose 1 phosphate
- Yeast make ethanol in order to:
A. Reoxidize NADH from glycolysis B. Have fun C. Make ATP in the process D. Eliminate lactic acid E. Reduce NAD for energy formation
- Protein kinase A (stimulated by glucagon) has the following effects EXCEPT :
A. Inhibits PFK- B. Stimulates glycogen phosphorylase C. Inhibits glycogen synthase D. Inhibits pyruvate dehydrogenase E. Inhibits pyruvate kinase
- Which of the following enzymes DOES NOT catalyze substrate level phosphorylation?
A. Pyruvate kinase B. Phosphoglycerate kinase C. Succinyl CoA synthetase D. PFK- E. All of them catalyze substrate level phosphorylation.
- Protein phosphatase-1, which reverses the action of protein kinase A, is activated by:
A. cAMP B. UDPG C. Free glucose D. Fructose-1-P E. None of the above
- Which of the following enzymes normally catalyze the re-oxidation of NADH produced in glycolysis?
A. Pyruvate dehydrogenase B. Glyceraldehyde-3-phosphate dehydrogenase C. Lactate dehydrogenase D. Isocitrate dehydrogenase E. α-ketoglutarate dehydrogenase
- How many ATP molecules are produced thorough substrate-level and oxidative phosphorylation as a result of the conversion of 1,3-bisphosphoglycerate into α-ketoglutarate?
A. 2 B. 4. C. 7 D. 9. E. 12
- All the following enzymes are critical in the regulation of glucose oxidation to CO 2 , EXCEPT :
A. PFK- B. pyruvate kinase C. Glyceraldehyde-3-phosphate dehydrogenase D. Pyruvate dehydrogenase E. Isocitrate dehydrogenase
- All the following vitamins/coenzymes are needed in the reactions catalyzed by the pyruvate dehydrogenase complex EXCEPT :
A. Niacin (needed for NAD) B. Pyridoxal phosphate C. Riboflavin D. Thiamine pyrophosphate (TPP) E. pantothenic acid (CoA)
- Which of the enzymes in the pyruvate dehydrogenase complex IS NOT allosterically regulated?
A. E 1 B. E 2 C. E 3 D. Kinase
- The oxidative step (NADH formation) during glycolysis occurs simultaneously with incorporation of inorganic phosphate.
- Insulin stimulates GLUT4 fusion in the brain cell membranes.
ESSAYS
- Insulin has to be injected in order to be effective. Recently a newly discovered product seems to mimic insulin action when taken orally, and could become the first oral treatment for Type I diabetes. Explain its proposed mechanism of action.
- Which is the effect of glucagon in the following activities? Answer: 9 , 8 or none.
Glycolysis in the liver
glycogen synthesis in the muscle
glycogen synthesis in the liver
glycogen degradation in the muscle
glycogen degradation in the liver
glucose concentration in plasma
- Which are the main differences between glycogen degradation in liver and muscle? What is the advantage of phosphorolysis instead of hydrolysis during this process in the muscle?
- The equilibrium between di-hydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G-3- P) favors the accumulation of DHAP. Explain why does glycolysis continue if the next reaction needs G-3-P.
- Explain in a few sentences the process of signal transduction. What is the main difference between the glucagon and insulin receptors?
BMD 322 Name............................................. EXAM #3-1 3-30-
- Which of the following IS NOT a gluconeogenic substrate
A. Acetoacetate B. Pyruvate C. Oxaloacetate D. Glycerol-P E. Malate
- Which enzyme(s) is(are) required to convert pyruvate into phosphoenol pyruvate?
A. Pyruvate carboxylase B. Pyruvate kinase C. Phosphoenol-pyruvate carboxykinase D. A and B are correct E. A and C are correct
- Conversion of PFK-2 to fructose 2,6 bisphosphatase by protein kinase A:
A. Activates PFK- B. Activates fructose 1,6 bisphosphatase C. Increases the intracellular concentration of fructose 2,6 bisphosphate D. Activates glucose-6-phosphatase E. Is inhibited by cAMP
- How many ATP molecules are required to make glucose from malate?
A. 1 B. 2 C. 3 D. 4 E. 6
- Several irreversible steps in glycolysis must be bypassed in gluconeogenesis by specific enzymes. The glycolytic steps include all of the following EXCEPT :
A. Phosphorylation of glucose to G-6-P B. Formation of fructose 1,6 bisphosphate C. Substrate level phosphorylation of ADP from 1,3-bisphosphoglycerate D. Substrate level phosphorylation of ADP from phosphoenol pyruvate E. No exceptions. All these steps are irreversible
- Which of the following dehydrogenases also catalyzes a decarboxylation?
A. NADH dehydrogenase B. Succinate dehydrogenase
- Cyanide stops electron transfer from cytochrome a 3 to oxygen. Which of the following processes is also blocked as a result of this inhibition:
A. Proton pumping stops B. NADH oxidation C. ATP formation D. Krebs cycle E. All of the above
- The TOTAL amount of ATP resulting from the complete oxidation of glucose to 6 CO 2 (if the glycerol phosphate shuttle is operating) is:
A. 10 B. 20 C. 27 D. 30 E. 32
- The enzyme translocase (ATP/ADP antiport)
A. Co-transports H+^ bound to ADP B. Takes negative charges from the matrix, at the expense of ∆ψ C. Requires Pi D. Utilizes the Fo component of Complex V E. Is a flavoprotein
- What is the role of apoprotein C-II?
A. To recognize LDL receptors B. To recognize receptors for chylomicron remnants C. To activate the pancreatic lipase D. To activate LPL (lipoprotein lipase) E. To carry free fatty acids
- Digested lipids in the intestine are packed and delivered as:
A. Chylomicrons B. VLDL C. LDL D. IDL E. HDL
- Arrange the following lipoproteins in order of increasing density:
A. VLDL > Chylomicrons > IDL > LDL B. Chylomicrons > VLDL > IDL > LDL C. IDL > Chylomicrons > VLDL > LDL D. VLDL > IDL >LDL > Chylomicrons E. Chylomicrons > LDL> IDL > VLDL
- Ketone bodies in the liver result indirectly from a combination of all the following processes EXCEPT :
A. Gluconeogenesis B. Energy is only provided by β-oxidation C. Accumulation of citrate D. Protein kinase A activation E. Increased cAMP
- The formation of acetoacetyl-CoA from acetoacetate in peripheral tissues requires:
A. ATP B. GTP C. Succinyl CoA D. Free CoA E. All of the above
- What is the role of carnitine?
A. Transports CoA B. Transports acyl-CoA C. Transports acyl groups D. Transports acetyl CoA E. Transports malate
- In the heart and the muscle, the reaction: stearoyl-CoA (18 C) ÷ palmitoyl-CoA (16 C) + 2 CO (^2) , results in the formation of _______ molecules of ATP:
A. 2 B. 4 C. 8 D. 14 E. 28
- Which of the following lipases is activated by phosphorylation?
A. Pancreatic lipase B. Lipoprotein lipase C. Pancreatic phospholipase A 2 D. None of the above E. All of the above
TRUE/FALSE
- All Krebs= cycle intermediates may be used for gluconeogenesis
- Ketone bodies are carried out as part of VLDL
- Fatty acid oxidation is the main source of energy for gluconeogenesis
BMD 322 Name............................................. FINAL EXAM - Version 1 5-4-
- According to the 2nd^ law of thermodynamics for a chemical reaction to be spontaneous:
A. The change in enthalpy (∆H) must be < 0 B. The change in the entropy of the universe (∆Su ) must be < 0 C. The change in free energy (∆G) must be < 0 D. The equilibrium constant (Keq) must be < 0 E. The change in standard free energy (∆G°=) must be < 0
- Which of the following vitamins is required for the function of transaminases?
A. Biotin B. Pyridoxal C. Vitamin D D. Riboflavin E. Niacin
- All of the following are functions of carbohydrates EXCEPT :
A. Structural B. Bacterial wall C. Energy storage D. Antigens E. Hormones
- What is the major component of the exoskeleton of crustaceans and insects?
A. Collagen B. Chitin C. Cellulose D. Hyaluronic acid E. Heparin
- Lysozyme is a natural antibiotic present in tears and saliva. Its mechanism of action involves:
A. Cleavage of a peptide bond in peptidoglycans B. Cleavage of a peptide bond in proteoglycans C. Inhibition of an enzyme involved in the synthesis of the bacterial wall D. Hydrolysis of a glycosidic bond E. None of the above
- The anomeric carbon in a sugar comes from:
A. Always the first carbon B. The last chiral carbon C. It depends on whether the sugar is a pentose or an hexose D. The carbonyl group E. It depends on whether the sugar is a pyranose or a furanose
- The individual components of fat include:
A. Glycerol and fatty acids B. Glycerol, fatty acids, phosphate and an alcohol C. Sphingosin D. Cholesterol E. All of the above
- The main difference between amylopectin and glycogen is:
A. Frequency of branching B. Types of glycosidic bonds C. Amylopectin does not have α 16 6 glycosidic bonds D. One of them has β-glycosidic bonds E. One of them is a structural polysaccharide
- Functions of cholesterol include the following EXCEPT :
A. Disrupts packing of phospholipids B. Changes the transition phase temperature C. Energy storage D. Hormone precursor E. Precursor of Vitamin D
- Passive diffusion of a solute across the membrane results in:
A. Equal concentrations in both sides of the membrane B. Higher concentration outside the membrane C. Energy spent in the movement of the solute D. Formation of a gradient across the membrane E. All of the above
- Which of the following enzymes catalyze substrate-level-phosphorylation:
A. ATP synthase B. Succinyl CoA synthetase (thiokinase) C. Pyruvate kinase D. A and B are correct E. B and C are correct
- How many molecules of NADH are produced during one turn of the Krebs= cycle?
A. 0 B. 1 C. 2 D. 3 E. 4
E. 3
- The energy for the synthesis of phosphoenol-pyruvate during gluconeogenesis comes from:
A. GTP B. ATP C. GTP and a decarboxylation D. ATP and a decarboxylation E. A H+^ gradient
- Each cycle in the β-oxidation of fatty acids produces all of the following EXCEPT :
A. NADPH B. Acetyl CoA C. FADH 2 D. A molecule of acyl CoA which is two carbons shorter E. All of the above are correct
- Malonyl CoA:
A. Stimulates glycolysis B. Inhibits carnitine-acyl transferase I C. Is a ketone body D. Is a precursor in cholesterol synthesis E. Is decarboxylated to acetyl CoA during fatty acid synthesis
- Which of the following dehydrogenases contains FMN and Fe-S clusters?
A. Malate dehydrogenase B. Glycerol-3-P dehydrogenase C. Fatty acyl CoA dehydrogenase complex D. Succinate dehydrogenase E. NADH-dehydrogenase
- All the following enzymes are inhibited by the action of protein kinase A EXCEPT :
A. PFK- B. Pyruvate kinase C. Pyruvate dehydrogenase D. Glycogen synthase E. Malonyl CoA synthetase
- Which of the following enzymes is activated by free glucose?
A. Glycogen synthase B. Protein phosphatase- C. PFK- D. PFK- E. None of the above
- All the following statements concerning insulin are correct EXCEPT:
A. It has receptors in adipose tissue B. Stimulates tyrosine kinase C. Causes its receptor to self-phosphorylate D. Increases the expression of GLUT4 in muscle E. Stimulates the release of free fatty acid
- Anabolic processes:
A. Cannot be allosterically modulated B. Involve oxidations C. Consume ATP D. Consume oxygen E. Are not subjected to hormonal control
- All of the following enzymes are found in the liver but not in adipose tissue EXCEPT :
A. Glycogen phosphorylase B. Glycerol kinase C. Malonyl CoA synthetase D. Glucokinase E. Glutaminase
- Roles of citrate include all of the following EXCEPT :
A. Precursor in the synthesis of fatty acids B. Precursor in the synthesis of cholesterol C. Precursor in the synthesis of ketone bodies D. Inhibitor of PFK- E. Carrier of mitochondrial acetyl CoA to the cytoplasm
- The energy for the addition of 2 carbons during fatty acid synthesis is provided by:
A. GTP B. ATP C. CTP D. A decarboxylation E. Hydrolysis of CoA
- Alanine is an example of a _________ amino acid:
A. Gluconeogenic B. Essential C. Aromatic D. Branched E. None of the above
