Exam 2 Review

Question 1

P450 cytochromes are members of which family of oxidoreductase?
A: Catalase
B: Hydroperoxidase C: Oxidase
D: Oxygenase

Answer 1

D

Question 2

Which of the following statements about the enzymes used in fructose metabolism is 1/1 incorrect (or False)?

A: Fructokinase phosphorylates Fructose from diet into Fructose 1-phosphate.

B: Aldolase A hydrolyzes Fructose 1-phosphate into Dihydroxyacetone phosphate and D-glyceraldehyde.

C: Thiokinase phosphorylates D-Glyceraldehyde into Glyceraldehyde 3-phosphate.

D: Aldolase B is the predominant form of the enzyme in the liver.

Answer 2

B

Question 3

Which of the following statements about enzymes in glycolysis and gluconeogenesis is 1/1 incorrect (or False)?

A: Glycerol-3-phosphate dehydrogenase reduced glycerol 3-phosphate into Dihydroxyacetone phosphate.

B: Phosphoenolcarboxykinase converts pyruvate into oxaloacetate

C: Malate dehydrogenase converts malate into oxaloacetate.

D: Fructose 1,6-bisphosphatase converts Fructose 1,6-bisphosphate into Fructose 6 phosphate.

Answer 3

A

Question 4

A patient visits his general practioner (GP) complaining of abdominal cramps and diarrhea after drinking milk. What is the most likely cause of the patient’s problem?
A: Lack of intestinal sucrase-isomaltase
B: Lack of intestinal lactase
C: Lack of pancreatic amylase
D: Lack of cellulase

Answer 4

B

Question 5

If a person decides to go on a crash diet and has only water for several days, which of the following molecules will exist in a higher concentration in the person’s blood?
A: Ketone bodies 
B: Insulin
C: Glucose
D: Triglycerides

Answer 5

A

Question 6

Statins have proved very effective against hypercholesterolemia, by which of these processes?
A: Inhibition of the conversion of HMGCoA to mevalonate
B: Inhibition of the conversion of Mevalonate to HMGCoA
C: Inhibition of the formation of Farnesyldiphosphate
D: Preventing absorption of cholesterol from tissues.

Answer 6

A

Question 7

Phosphatidylinositol is hydrolyzed to Diacylglycerol (DAG) and Inositol triphosphate (IP3), using which of the following enzymes?
A: Phospholipase B 
B: Phospholipase C 
C: Phospholipase D 
D: Phospholipase A2

Answer 7

B

Question 8

The subcellular site of the breakdown of long chain fatty acids to acetylCoA via beta oxidation is which of the following?
A: The cytosol
B: the matrix in the mitochondria.
C: The endoplasmic reticulum.
D: The intermembrane space of the mitochondria.

Answer 8

B

Question 9

Which of the following statements about gangliosides is incorrect (or False)?
A: They are derived from galactosylceramide.
B: They contain one or more molecules of sialic acid.
C: They are present in nervous tissue in high concentrations.
D: The ganglioside, GM1 is the receptor for cholera toxin in the human intestine.

Answer 9

A

Question 10

Which of the following statements is incorrect (or False)?
A: Ca+2 activates Phosphorylase kinase b to Phosphorylase kinase a, by phosphorylation.
B: Ca+2 activates Phosphorylase kinase b to Phosphorylase kinase a, by dephosphorylation.
C: Ca+2 activates Glycogen synthase ‘b’ to glycogen synthase ‘a’ by dephosphorylation.
D: Phosphodiesterase deactives cAMP by hydrolysis.

Answer 10

B

Question 11

Which of the following statements is incorrect (or False)?
A: Pyruvate carboxylase catalyzes the carboxylation of pyruvate to oxaloacetate.
B: Phosphoenolpyruvate carboxykinase catalyzes the decarboxylation and phosphorylation of oxaloacetateto Phosphoenolpyruvate.
C: Pyruvate Dehydrogenase converts Lactate into Pyruvate.
D: Action of Adenylyl cyclase of ATP, followed by phosphodiesterase converts ATP into 5’ AMP.

Answer 11

C

Question 12

Which of these statements is incorrect (or False)?
A: Cholesterol is synthesized in the body entirely from AcetylCoA, and cholesterol synthesis in the liver is regulated partly by cholesterol in the diet.
B: Glycolipids are important constituents of nervous tissue such as brain and the outer leaflet of cell membranes.
C: Fluidity of a fatty acid increases with chain length and decreases with increase in the degree of unsaturation.
D: Eicosanoids make up an important group of physiologically and pharmacologically active compounds such as prostaglandins, thromboxanes, leukotrienes and lipoxins.

Answer 12

C

Question 13

Which of the following statements is incorrect (or False?)
A: Fatty acid synthase has 6 enzyme activities.
B: The main source of NADPH for lipogenesis is the Oxidative process of Pentose Phosphate Pathway.
C: 3 moles of NADPH is used in one cycle of biosynthesis of fatty acid.
D: Elongation of Fatty acid chain occurs in the Endoplasmic reticulum.

Answer 13

C

Question 14

Which of the following statements is incorrect (or False)?
A: Lipogenesis occurs in the mitochondria.
B: Production of MalonylCoA is the first step in fatty acid synthesis.
C: Biotin is the vitamin required for carboxylation of AcetylCoA.
D: AcetylCoA Carboxylase will carboxylate AcetylCoA to MalonylCoA.

Answer 14

A

Question 15

Which of the following statements is incorrect (or False)?
A: Linoleic and alpha Lenolenic acids are the only fatty acids known to be essential fatty acid.
B: Arachidonic acid can be derived from linoleic acid, in most mammals.
C: The first double bond introduced into a saturated fatty acid is nearly always in the delta-9 (9th position).
D: Plants cannot synthesize nutritionally essential fatty acids by introducing double bonds at delta-9 (9th carbon) or delta-12 (12th carbon) or delta-15 (15th carbon)

Answer 15

D

Question 16

Which of the following statements is incorrect (or False)?
A: Geranyl diphosphate gives rise to Dolichol and Ubiquinone.
B: Mevalonate is the reduced product of HMG CoA.
C: Statins inhibit the action of HMG CoA reductase.
D: Mevalonate is converted to Mevalonate 3-phospho-5-diphosphate and then decarboxylated to Isopentyldisphosphate.

Answer 16

A

Question 17

Which of the following statements is incorrect (or False)?
A: Oxidation of Fatty acids occurs in the mitochondria.
B: Long chain fatty acids penetrate the inner mitochondrial membrane as Carnitine derivatives.
C: One cycle of beta oxidation of fatty acid produces one NADH and one FADH2 molecule.
D: Oxidation of Fatty acids with an odd number of carbon atoms yields AcetylCoA and a SuccinylCoA molecule.

Answer 17

D

Question 18

Which of the following statements is incorrect (or False)?

A: Carnitine is beta hydroxy-gamma trimethylammonium butyrate.
B: Ketogenesis is regulated at two steps.
C: If Stearic acid is metabolized, 9 AcetylCoA’s are formed along with 8 NADH and 8 FADH2 molecules.
D: Peroxisomes can oxidize the fatty acid - docasahexenoic acid (DHA or Cervonic acid).

Answer 18

B

Question 19

Which of the following statements is incorrect (or False)?

A: Free fatty acid is converted to AcylCoA by the enzyme Acyl-CoA synthetase.
B: HMG-CoA synthetase synthesizes HMG from acetoacetylCoA and AcetyCoA.
C: HMG-CoA lyase hydrolyzes HMGCoA into acetoacetate and AcetylCoA.
D: 3-hydroxybutyrate dehydrogenase will oxidize the C=O (carbonyl or oxo) group of acetoacetate

Answer 19

D

Question 20

Which of the following statements is incorrect (or False)?
A: 2 moles of AcetylCoA is required to produce Acetoacetate.
B: Decarboxylation of Acetoacetate produces Acetone.
C: Reduction of acetoacetate produces alpha hydroxybutyrate (or alpha hydroxybutanoate).
D: Ketone bodies serve as fuel for extrahepatic tissues.

Answer 20

C

Question 21

Which of the following statements is incorrect (or False)? 0/1
A: Long chain omega-3 fatty acids promote the synthesis of less inflammatory prostaglandins and leukotrienes.
B: Phophatidylcholine plays a role in programmed cell death (apoptosis).
C: Peroxidation of lipids containing saturated fatty acids lead to a generation of free radicals that damage tissue and cause disease.
D: Lecithin is a condensation product of phosphatidic acid and Choline.

Answer 21

C

Question 22

Which of the following statements is incorrect (or False)? 1/1
A: Triglycerides contain a glycerol and three fatty acids, where the 2nd fatty acid is unsaturated.
B: Phosphatidic acid contains a glycerol molecule to which two fatty acids are condensed on the 1st and 2nd carbon and the 3rd carbon has a phosphate ester group.
C: When phosphatidic acid is condensed with Choline, it is referred to as Lecithin.
D: When phosphatidic acid is condensed with Ethanolamine, it is referred to as Lecithin

Answer 22

D

Question 23

Which of the following statements is incorrect (or False)?
A: Oleic acid contains 18 C’s, 1 double bond and it is a C-9 from the COOH group.

B: Linoleic acid contains 18 C’s, 2 DBs and the DBs start at C-9 and C-12 from the COOH group.

C: Linolenic acid contains 18 C’s, 3 DBs and the DBs start at C-9, C-12 and C-15 from the COOH group.

D: Arachidic acid contains 20 C’s, 4 DBs, starting at C-5, C-8, C-11 and C-14 from the COOH group.

Answer 23

D

Question 24

Which of the following statements is incorrect (or False)?
A: Phosphatidic acid contains a glycerol molecule to which two fatty acids are condensed on the 1st and 2nd carbon and the 3rd carbon has a phosphate ester group.

B: Arachidonic acid contains 20 C’s, 4 DBs, starting at C-5, C-8, C-11 and C-14 from the COOH group.

C: Bile acids are derived from cholesterol or oxidation products of cholesterol.

D: Glycolipids contain a sphingosine molecule to which is attached a fatty acids at the amine group and a phosphate and a choline molecule at the primary alcohol.

Answer 24

D

Question 25

Which of the following statements is incorrect (or False)?
A: Lysophosphatidylcholine is choline where the #2 Fatty acid has been hydrolyzed by an enzyme.
B: Phosphotidylinositol 4,5bisphosphate is hydrolyzed into diacylglycerol (DAG) and inositol triphosphate (IP3) which act as secondary messengers.
C: Polymerization of isoprene unit results in formation of the polyprenoid tail of CoQ, long chain alcohol, Dolichol and cholesterol.
D: Gangliosides are glycosphingolipids containing Neuraminic acid (NeuAc) and is present in nervous tissues in low concentration.

Answer 25

D

Question 26

Which of the following statement is incorrect (or False)? 0/1
A: Glycolipids contain a sphingosine molecule to which is attached a fatty acid at the amine group and a glycosidic bond at the primary alcohol.
B: Cardiolipin is only found in the mitochondria and is essential for the mitochondrial function.
C: Plasmalogen is structurally similar to Phosphatidylethanolamine but contains an unsaturated ester on carbon 1 of glycerol.
D: A sphingomyelin contains a sphingosine molecule, to which a fatty acid is attached to the primary amine group, and a choline-P (phosphate) molecule is attached to the primary alcohol group.

Answer 26

C

Question 27

Which of the following statement is incorrect (or False)? 1/1
A: Cardiolipin is only found in the mitochondria and is essential for the mitochondrial function.
B: Plasmalogen is structurally similar to Phosphatidylethanolamine but contains an unsaturated ether on carbon 1 of glycerol.
C: A sphingomyelin contains a sphingosine molecule, to which a fatty acid is attached to the primary amine group, and a choline-P (phosphate) molecule is attached to the primary alcohol group.
D: Bile acids are derived from Cephalins.

Answer 27

D

Question 28

Which of the following statement is incorrect (or False)? 0/1
A: Prostaglandins, leukotrienes and thromboxanes can be synthesized from Arachidonic acid.
B: Taurocholate is a derivative of Cholesterol (or synthesized by oxidation of cholesterol).
C: Mineralocorticoids such as Cortisol regulate carbohydrate metabolism.
D: Lecithin is classified as a glycerophospholipid.

Answer 28

C

Question 29

Which of the following statement is correct (or True)?
A: Peroxisomes oxidize very long chain fatty acids.
B: Ketogenesis occurs when there is a high rate of lactic acid oxidation in the liver.
C: HMG or (HMG CoA) is formed using 2 moles of AcetylCoA.
D: If Arachidonic acid is metabolized (or beta oxidized), it will produce 9 moles of AcetylCoA.

Answer 29

B

Question 30

Which of the following is incorrect (or False)?
A: In the formation of Cholic acid from Cholesterol by oxidation, the first enzyme that acts on Cholesterol is 12 alpha hydroxylase.
B: Glycocholic and Taurocholic acids are classified as primary bile acids.
C: Six isoprenoid units form squalene.
D: Two molecules of farnesyl diphosphate condense at the diphosphate end to form squalene.

Answer 30

A

Question 31

Which of the following determines blood type O in the ABO blood typing system?
A: the presence of only N-acetyl-D-galactosamine antigen
B: the presence of only N-acetyl-D-galactose antigen
C: the presence of both N-acetyl-D-galactosamine and N-acetyl-D-galactose antigens
D: the absence of both N-acetyl-D-galactosamine and N-acetyl-D-galactose antigens.

Answer 31

D

Question 32

Which of the following statements about the pentose phosphate pathway (PPP) is correct? 1/1
A: The pentose phosphate pathway is especially important in tissues that are synthesizing fatty acids. B: The PPP provides an alternative to glycolysis only in the fasting state.
C: The PPP is the only source of NADPH for fatty acid synthesis.
D: Glucose 6-phosphate is converted to 6-phosphoglucate by decarboxylation.

Answer 32

A

Question 33

Which of the following statements about glycogen metabolism is correct (or True)?
A: The plasma concentration of glycogen increases in the fed state.
B: Liver synthesizes more glycogen when the hepatic portal blood glucose concentration is high.
C: Muscle synthesizes glycogen in the fed state because glycogen phosphorylase is activated in response to Insulin. D: Glycogen is synthesized in the liver in the fed state and then exported to other tissues as low density lipoproteins.

Answer 33

B

Question 34

Xanthine oxidase catalyzes which of the following reactions? 
A: Reduction of Pyrimidine to Uric acid
B: Oxidation of Purines to uric acid
C: Oxidation of Purine to caffeine
D: Reduction of Purine to beta alanine

Answer 34

B

Question 35

Peroxisomes are rich in oxidases and which of the following enzymes? 
A: Dehydrogenases 
B: Oxygenases
C: Peroxidase
D: Catalase

Answer 35

D

Question 36

Which of the following statements is incorrect (or False)?
A: Thiolase hydrolyzes acetoacetylCoA and also condenses two moles of acetylCoA.
B: HMG lyase hydrolyzes HMG into AcetyCoA and beta hydroxybutyrate.

C: AcylCoA synthetase condenses free fatty acid with Coenzyme A (CoA).

D: CoA transferase transfer CoA from SuccinylCoA (of citric acid cycle) into AcetoacetylCoA.

Answer 36

B

Question 37

Which of the following statements is incorrect (or False)?
A: Glycoproteins are O-linked, N-linked or GPI(Glycosylphosphatidylinositol) linked proteins that contain branched or unbranched oligosaccharide chains.

B: Heparan sulfate, chrondroitin sulfates, and Keratin sulfates are some examples of Glycosaminoglycans (GAGs).

C: Beta D-glucopyranosyl (1–>4) beta D-glucopyranosyl is the IUPAC name of Lactose.

D: Neuraminic acid is a 9 carbon sugar derived by condensing Mannosamine with Pyruvate.

Answer 37

C

Question 38

Which of the following statements about regulatory and adaptive enzymes associated with carbohydrate metabolism is incorrect (or False)?
A: In fasting and diabetes, Glycogen synthase activity decreases.
B: In fasting and diabetes, Pyruvate carboxylase activity increases.
C: In fasting and diabetes, Glucose 6-phosphatase activity increases.
D: In fasting and diabetes, Phosphoenolcarboxykinase activity decreases.

Answer 38

D

Question 39

Which of the following statements about glycogen storage diseases is incorrect (or False)?
A: Von Gierke disease is the result of Glucose 6-phosphate.
B: Forbe or Cori disease is due to the deficiency in liver and muscle debranching enzyme.
C: Hers disease is the result of the deficiency in liver phosphorylase.
D: Glycogen storage diseases are not inherited.

Answer 39

D

Question 40

Which of the following statements is correct (or True)?
A: Citrate synthase (oxaloacetate to citrate) is classified as an Oxidoreductase
B: Fumarase (Fumarate to Malate) is classified as ligase
C: Succinate thiokinase (Succinyl CoA to Succinate) is classified as a hydrolase and a transferase
D: Malate Dehydrogenase (Malate to oxaloacetate) is classified as a transferase.

Answer 40

C

Question 41

Which of the following statements is correct (or True)?
A: Citrate synthase (oxaloacetate to citrate) is classified as an Oxidoreductase.
B: Fumarase (Fumarate to Malate) is classified as ligase.
C: Succinate thiokinase (Succinyl CoA to Succinate) is classified as a hydrolase and a transferase.
D: Malate Dehydrogenase (Malate to oxaloacetate) is classified as a transferase.

Answer 41

C

Question 42

Which one of the following statements is not correct (or False)?
A: Steric hindrance by histidine E7 plays a critical role in weakening the affinity of hemoglobin or carbon monoxide (CO).
B: Carbonic anhydrase plays a critical role in respiration by virtue of its capacity to break down 2,3- bisphosphoglycerate in the lungs.
C: Hemoglobin S is distinguished by a genetic mutation that substitutes Glu6 on the β subunit with Val, creating a sticky patch on its surface.
D: Oxidation of the heme iron from +2 to the +3 state removes (or disables) the ability of hemoglobin to bind oxygen.

Answer 42

B

Question 43

Which of the following statements is not correct (or False)?

A: Collagen is not synthesized as a larger precursor.
B: Alzheimer’s disease is related to refolding or misfolding of another protein endogenous to human brain tissue, beta amyloid.
C: Beta thalassemias are caused by genetic defects that impair the synthesis of one of the polypeptide
D: Prion diseases may manifest themselves as infectious, genetic or sporadic disorders.

Answer 43

A

Question 44

Which of the following is a primary substrate for gluconeogenesis?
A: Galactose B: Glycerol C: Glycogen D: Sucrose

Answer 44

B

Question 45

A certain class of disease is produced because of the tissue’s lack of certain metabolic pathways. Which of the following tissues can metabolize glucose, fatty acids and ketone bodies for ATP production?
A: Liver
B: Muscle
C: Brain
D: Red blood cells

Answer 45

B

Question 46

A newborn infant has several issues including low muscle tone, rapid respiratory rate etc. A liver biopsy of a newborn infant reveals a very low level of AcetylCoA carboxylase but normal levels of glycolysis and gluconeogenesis, citric acid and pentose phosphate pathway enzymes. Which of the following is the most likely cause of the infant’s respiratory enzymes?
A: low levels of phosphatidylcholine 
B: Ketoacidosis
C: High levels of citrate
D: Biotin deficiency

Answer 46

A

Question 47

47 Oligomycin is one of the several respiratory poisons with direct effects on the respiratory chain. Oligomycin inhibits which of the following enzymes during oxidative
phosphorylation?
A: Pyruvate kinase
B: Glucose 6-phosphate dehydrogenase 
C: Enolase
D: ATPase

Answer 47

D

Question 48

Which of the following statements about the pentose phosphate pathway is incorrect (or False)?

A: Glucose 6-phosphate dehydrogenase oxidizes glucose to gluconate.
B: Glucose 6-phosphate dehydrogenase decarboxylates gluconate to Ribose 5-phosphate.
C: Genetic deficiency of glucose 6-phosphate dehydrogenase causes acute hemolysis of red blood cells. D: Deficiency/disruption in the uronic acid pathway leads to a condition called as essential pentosuria.

Answer 48

B

Question 49

Which of the following statements about enzymes in fatty acid synthesis is incorrect (or False)?
A: 3-ketoacylCoA synthase condenses AcylCoA and MalonylCoA to form 3-ketoacylCoA.

B: 3-ketoacylCoA reductase reduces the beta oxo (or carbonyl) group of 3-ketoacylCoA

C: 3-hydroxyacylCoA dehydratase dehydrates 3-hydroxyacylCoA to an alpha beta unsaturated enoylCoA.

D: Thioesterase hydrolyzes the acylgroup from Fatty acid synthase

Answer 49

B

Question 50

Which of the following statements about enzymes is incorrect (or False)?
A: Pyruvate dehydrogenase carboxylates AcetylCoA to pyruvate.
B: Citrate lyase hydrolyzes citrate into oxaloacetate and AcetylCoA.
C: Malic enzyme will decarboxylate malate to pyruvate.
D: AcetylCoA carboxylase converts AcetylCoA into MalonylCoA.

Answer 50

A

Question 51

51 Which of the following will provide the main fuel for muscle contraction during short term, maximum exertion?
A: Muscle glycogen
B: Plasma glucose
C: Muscle reserves of triacylglycerol 
D: Ketone bodies

Answer 51

A

Question 52

Which of the following statements about glycolysis and gluconeogenesis is correct (or True)?
A: Fructose cannot be used for gluconeogenesis in the liver because it is phosphorylated to Fructose 6P

B: Glycolysis can proceed under anaerobic conditions only if pyruvate is formed from lactate in the muscle

C: Red blood cells only metabolize glucose by anaerobic glycolysis and the pentose phosphate pathway.

D: The reverse of glycolysis is the pathway for gluconeogenesis in skeletal muscle.

Answer 52

C

Question 53

Which of the following statements is incorrect (or False)?
A: Increased fatty acid oxidation leads to ketosis.
B: Increased production of ketone bodies over a long period of time causes ketoacidosis.
C: Impairment in fatty acid metabolism leads to hyperglycemia.
D: Increased fatty acid oxidation leads to Ketonemia or Ketonuria.

Answer 53

C

Question 54

Which of the following statements about bile acids (or salts) is incorrect (or False)?
A: Primary bile acids are synthesized in the liver from cholesterol.
B: The secondary bile salts are produced by the hydrolysis and reduction (dehydroxylation) of primary bile salts.
C: The secondary bile salts are produced by the conjugation and reduction (dehydroxylation) of primary bile salts.
D: Deoxycholic and Lithocholic acids are classified as secondary bile acids.

Answer 54

C

Question 55

Tay Sachs disease is a lipid storage disease caused by genetic defect in deficiency in  which of the following enzymes?
A: Hexosaminidase A 
B: beta galactosidase 
C: Ceramidase
D: beta glucosidase

Answer 55

A

Question 56

Which of the following is the major product of fatty acid synthase?
A: Oleate
B: Palmitate
C: Acetoacetate 
D: Stearate

Answer 56

B

Question 57

Which one of the following statements about glucose metabolism is correct (or True)?
A: Glucagon increases the rate of glycolysis.
B: The main product of glycolysis in red blood cells is pyruvate.
C: Glucose is cleaved into Glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.
D: Substrate level phosphorylation takes place in the electron transport system.

Answer 57

C

Question 58

Which of the following statements is incorrect (or False)?

A: Alanine is converted to Pyruvate by transmination.
B: GLUT 4 is a glucose uptake transporter present in the heart, skeletal and adipose tissue.
C: Glucagon is the hormone produced in the alpha cells of the pancreatic islets in response to hyperglycemia.
D: Insulin is the hormone produced in the beta cells of the pancreatic islets in response to hyperglycemia.

Answer 58

C

Question 59

Which of the following statements is incorrect (False)?
A: Phosphorylase a is the enzyme that hydrolyzes glycogen one glucose unit at a time.

B: Glycogen synthase is the enzyme that is used for the synthesis of glycogen.

C: Decrease in concentration of Glucose 6-phosphate (Glc-6P) activates phosphorylase (or glycogen phosphorylase).

D: Increase in concentration of Glucose 6-phosphate (Glc-6P) activates Glycogen synthase

Answer 59

B

Question 60

Which of the following statements is incorrect (or False)?
A: Inhibition of pyruvate metabolism leads to lactic acidosis.
B: Glycolysis is activated by three enzymes catalyzing non equilibrium reactions: hexokinase, phosphofructokinase and pyruvate kinase.
C: Pyruvate is inhibited by its products, acetylCoA and NADH.
D: Oxidation of pyruvate to AcetylCoA is an equilibrium or reversible route from glycolysis to the citric acid cycle.

Answer 60

D

Question 61

Consider the action of Fructofructokinase-2 (PFK-2). Which of the following statement about PFK-2 is incorrect (or False)?
A: Increase in concentration of Fructose 2,6-bisphosphate leads to increase in action of PFK-1 and therefore increase in glycolysis.

B: During fasting, the cAMP dependent protein kinase inactivates the kinase (PFK-2) and activates fructose 2,6- bisphosphatase.

C: Fructose 1,6-bisphosphate is hydrolyzed by Fructose 1,6-bisphosphatase to Fructose 6 phosphate.

D: The most potent positive allosteric activator of Phosphofructokinase 1 (PFK-1) is Fructose 1,6-bisphosphate.

Answer 61

D

Question 62

Which of the following statements about glycogen metabolism is incorrect (or False)?
A: cAMP integrates the regulation of glycogenolysis and glycogenesis.
B: cAMP simultaneously promotes activation of phosphorylase and inhibition of glycogen synthase.
C: Insulin inhibits glycogenolysis and stimulates glycogenesis.
D: Muscle can also produce glucose by hydrolyzing Glucose 6-phosphate into Glucose.

Answer 62

D

Question 63

Which of the following is true of the spatial distribution of the hydroxyl groups of Beta-D-glucopyranose?
A: They are all in axial positions.
B: They are all in equatorial positions.
C: The hydroxyl on C-1 is axial, those on C-2, C-3 and C-4 are equatorial.
D: The hydroxyl on C-1 is equatorial, those on C-2, C-3 and C-4 are axial.

Answer 63

B

Question 64

Consider the citric acid cycle; which of the following statement is correct (or True)? 0/1
A: NADH is used in the process of oxidation of Malate to Oxaloacetate.
B: FAD is used in the process of reduction of succinate to fumarate
C: Malate dehydrogenase, isocitrate dehydrogenase and succinate dehydrogenase all use NAD+ for oxidation/reduction reactions.
D: NAD+ is used for the oxidation of Isocitrate to Oxalosuccinate (or ketoglutarate)

Answer 64

D

Question 65

Which of the following statements about the synthesis of cholesterol is incorrect (or 0/1 False)?
A: Geranyldiphosphate is used to make the side chain of ubiquinone
B: Farnesyldiphosphate is used to make the side chain of prenyated proteins
C: 3,3-dimethylallyldisphosphate and isopentyldisphosphate combine to make geranyldisphosphate
D: Two farnesyldiphosphate units combine to make squalene

Answer 65

A

Question 66

In the citric acid cycle, which of the following statement is correct (or True)?
A: NADH is used in the process of oxidation of Malate to Oxaloacetate.

B: FAD is used in the process of reduction of succinate to fumarate.

C: Malate dehydrogenase, isocitrate dehydrogenase and succinate dehydrogenase all use NAD+ for oxidation/reduction reactions.

D: NAD+ is used for the oxidation of Isocitrate to Oxalosuccinate (or ketoglutarate).

Answer 66

D

Question 67

Which of the following statements is incorrect (or False)?
A: Glycine+Arginine+S-Adenosylmethionine can be used to make Creatine.
B: Serotonin can be made by decarboxylation of 5-hydroxytrytophan.
C: Melatonin is a derivative of (or can be synthesized from) amino acid, Tyr.
D: Melatonin is synthesized by Acetylation of the amine group and methylation of the hydroxyl group of Serotonin.

Answer 67

C

Question 68

Which of the following is correct (or True) about the following isoenzymes?
A: Lactate Dehydrogenase (LDH) has 3 isoenzymes and Creatine Kinase (CK) has five isoenzymes

B: Levels of LDH isoenzymes help identify a particular injured tissue, while CK-MB has a useful diagnostic window and is found predominantly in the heart and skeletal muscle.

C: In LDH, isozyme I1 or H4 is found predominantly in the liver and isozyme, I5 or M4 is found in the heart.

D: CK-MB is an isoenzyme of CK that has a useful diagnostic window and is found predominantly in the brain tissue.

Answer 68

B

Question 69

Which of the following statements is incorrect (or False)? 1/1

A: Arginine is used to make NO (Nitric oxide) by the action of NO Synthase.
B: Cysteine participates in the biosynthesis of Coenzyme A
C: Decarboxylation of amino acid, His forms Histamine
D: Amino acid, Tyr is used by neural cells to form only norepinephrine and not epinephrine.

Answer 69

D

Question 70

Which one of the following statement is not correct (or False)?
A: Interconvertible enzymes fulfill key roles in integrated regulatory networks.

B: Phosphorylation of an enzyme often alters its catalytic effiiciency.

C: The ability of protein kinases to catalyze the reverse reaction that removes the phosphoryl group is key to the versatility of this molecular regulatory mechanism.

D: Zymogen activation by partial proteolysis is irreversible under physiological conditions

Answer 70

D

Question 71

A number of compounds inhibit oxidative phosphorylation—the synthesis of ATP from ADP and inorganic phosphate linked to oxidation of substrates in mitochondriA. Which of the following describes the action of oligomycin?

A: It discharges the proton gradient across the mitochondrial inner membrane.
B: It inhibits the electron transport chain directly by binding to one of the electron carriers in the mitochondrial inner membrane.
C: It inhibits the transport of ADP into, and ATP out of, the mitochondrial matrix.
D: It inhibits the transport of protons back into the mitochondrial matrix through ATP synthase.

Answer 71

D

Question 72

Consider the Bohr’s effect exhibited by Hemoglobin. Which of the following is correct (or 0/1 True) for Hemoglobin?

A: Increase in [CO2] and decrease in pH value will help buffering action.
B: Amino acid His-146 on the alpha chain gets protonated and forms a salt bridge with the amino acid, Asp.
C: There are 2 moles of protons being transported by His-146 on the alpha chain.
D: Decrease in [CO2] and increase in pH value will help buffering action.

Answer 72

A

Question 73

Which of the following statements is not correct (or False)?
A: Glycogen phosphorylase cleaves the alpha 1,4 glycosidic bond in glycogenolysis.
B: Glucose 6-phosphatase dephosphorylates Glucose 6 phosphate to Glucose in the muscle.
C: Debranching enzyme cleaves the alpha 1,6 glycosidic bond in glycogen.
D: Glycogen synthase forms the alpha 1,4 glycosidic bond in glycogenesis.

Answer 73

B

Question 74

Which of the following compounds is recycled in the citric acid cycle and thus serves a  catalytic role?
A: AcetylCoA
B: Citrate
C: Oxaloacetate 
D: Succinate

Answer 74

C

Question 75

Which of the following explains why individuals with hyperlipidemia and/or gout should minimize their intake of sucrose and high fructose syrups?
A: Fructose bypasses the regulatory steps catalyzed by phosphofructokinase (PFK-1) and undergoes rapid glycolysis in the liver.
B: Fructokinase acts on glucose and increases its metabolism.
C: Hexokinase catalyzes the phosphorylation of fructose over glucose and therefore it undergoes metabolism very rapidly.
D: Fructose is rapidly metabolized by Aldolase A.

Answer 75

A

Question 76

Children with a variety of organic acidemias will complex excess intermediates with carnitine as abnormal acylcarnitines and deplete free carnitine. The unavailability of carnitine to translocate fatty acids into mitochondria will cause which of the following?

A: Inhibition of ATP synthase
B: Depletion of NADH needed for oxidation
C: Inhibition of cytochrome oxidase
D: Uncoupling of oxidation from phosphorylation.

Answer 76

B

Question 77

Individuals with disorders of the respiratory chain are often places on supplements containing riboflavin and Coenzyme Q. Which of the following is the role of coenzyme Q in the respiratory chain?

A: It links flavoproteins to cytochrome b.
B: It links NAD dependent dehydrogenases to cytochrome b.
C: It links each of the cytochromes in the respiratory chain to one another
D: It is the first step in the respiratory chain.

Answer 77

A

Question 78

A patient’s chart for lab findings/results demonstrates elevated serum triglycerides esterified with long chain fatty acids and borderline low glucose. Muscle biopsy shows increased number of lipid vacuoles. Which of the following is the most likely diagnosis?

A: Carnitine deficiency.
B: Biotin deficiency
C: Fatty acid synthase deficiency
D: Carnitine deficiency.

Answer 78

A

Question 79

Nerve stimulation of skeletal muscle causes the release of calcium from sarcoplasmic reticulum and leads to muscle contraction. Simultaneously, the increased calcium concentration causes which of the following responses?

A: Activation of phosphorylase kinase
B: Activation of protein phosphatase
C: Inactivation of glycogen phosphorylase
D: Activation of cyclic AMP phosphodiesterase

Answer 79

A

Question 80

Which of the following statements about diseases is incorrect (or False)?

A: Fructose and Sorbitol in the lens are associated with Diabetic Cataract.
B: In the liver, fructose increases fatty acid and triacylglycerol synthesis leading to increased triglyceride and LDL cholesterol synthesis.
C: Glucosuria occurs when the renal threshold for glucose is not exceeded (or decreases).
D: Inability to metabolize galactose occurs in galactosemias.

Answer 80

C

Question 81

Which of the following statements about enzymes in glycolysis and gluconeogenesis is incorrect (or false)?
A: Glucose 6-phosphatase hydrolyzes glucose 6P to glucose
B: Phosphofructokinase-1 (PFK-1)phosphorylates Fructose 6 phosphate into Fructose 2,6 bisphosphate. C: Pyruvate dehydrogenase converts Phosphoenolpyruvate into Pyruvate
D: Pyruvate carboxylase converts Pyruvate into Oxaloacetate

Answer 81

C

Question 82

Which of the following statements about fed and fasting metabolic states is correct (or True)?
A: In the fasting state, ketone bodies are synthesized in the liver
B: In the fed state, insulin acts to increase the synthesis of glucagon.
C: In the fasting state, glucagon acts to increase the activity of lipoprotein lipase in adipose tissues. D: In the fed state, there is decreased secretion of insulin.

Answer 82

A

Question 83

A person eats a diet very high in carbohydrates. Which of the following molecules will have 1/1 a higher concentration?
A: Glucose
B: Glucagon
C: Ketone bodies D: Alanine

Answer 83

A

Question 84

Which of the following statements concerning biosynthesis of cholesterol is correct?
A: The rate limiting step is the formation of 3-hydroxy-3-methylglutarylCoA (HMG). B: Synthesis occurs in the cytosol of the cell.
C: Mevalonate is the reduced product of HMG.
D: Mevalonate is the oxidized product of HMG.

Answer 84

C

Question 85

The body requires Choline phosphate molecule which it can get from the hydrolysis of a 0/1 Lecithin. Which of the following lipases would be used for this purpose?
A: Phospholipase A1 B: Phospholipase A2 C: Phospholipase C D: Phospholipase D

Answer 85

C

Question 86

Ketone bodies are mainly used for which one of the following processes?
A: Conversion to fatty acids for storage of energy. B: Generation of energy in the tissues.
C: Generation of energy in the liver.
D: Generation of energy in red blood cells.

Answer 86

B

Question 87

Which of the following is a chain breaking antioxidant?
A: Glutathione peroxidase B: Selenium
C: Superoxide dismutase D: Catalase

Answer 87

C

Question 88

Which of the following statements is correct (or True)?
A: Tissue that function under aerobic conditions, produce lactate
B: When Pyruvate is converted to lactate, NAD+ is reduced to NADH + H+.
C: Pyruvate dehydrogenase has 9 serine residues that get phosphorylated.
D: Pyruvate kinase is a transferase enzyme that converts Phosphoenolpyruvate to pyruvate

Answer 88

D

Question 89

Which of the following statements is correct (or True)?
A: Increase in cAMP concentration, increases phosphorylation reaction.
B: In the liver, the role of glycogen is to provide Glucose 6P.
C: In the muscle the role of glycogen is to provide Glucose.
D: Glycogen synthase contains two enzymes – the Glucan transferase and the debranching enzyme.

Answer 89

A

Question 90

Which of the following statements is incorrect (or False)?
A: Protein phosphatase-1 inactivates Glycogen Phosphorylase B: cAMP activates Glycogen Phosphorylase.
C: Phosphorylase ‘a’ is made active by dephosphorylation.
D: Glycogen synthase is made active by dephosphorylation.

Answer 90

C

Question 91

Which of the following statements is incorrect (or False)?
A: Pyruvate dehydrogenase (PDH) is activated by dephosphorylation of 3 serine residues. B: PDH Kinase is activated by a higher ratio of [CoA]/[Acetyl CoA]
C: PDH Kinase is activated by a lower ratio of [NAD+]/[NADH]
D: PDH Kinase is activated by a lower ratio of [ATP]/[ADP].

Answer 91

D

Question 92

Which of the following statements is incorrect (or False)?
A: When phosphorylase kinase ‘a’ is activated by phosphorylation, Glycogen synthase is deactivated by phosphorylation.
B: When phosphorylase kinase ‘a’ is activated by dephosphorylation, Glycogen synthase is activated by phosphorylation.
C: When phosphorylase kinase ‘a’ is deactivated by hydrolysis of the phosphate group, Glycogen synthase is activated by dephosphorylation.
D: Protein phosphatase-1 dephosphorylates Phosphorylase ‘a’ and Glycogen synthase ‘b’.

Answer 92

B

Question 93

Which of the following statements is correct (or True)?
A: The oxidative phase of PPP generates NADPH
B: The non oxidative phase of PPP generates NADPH C: The oxidative phase of PPP generates NADP+
D: The oxidative phase generates Ribose precursors

Answer 93

A

Question 94

Which of the following statements is correct (or True)?
A: Triglycerides contain a glycerol and three fatty acids, where the 3rd fatty acid is unsaturated.
B: Phosphatidic acid contains a glycerol molecule to which two fatty acids are condensed on the 1st and 3rd carbon and the 2nd carbon has a phosphate ester group.
C: Plasmalogens occur in brain and muscle.
D: When phosphatidic acid is condensed with serine, it is referred to as Lecithin.

Answer 94

C

Question 95

Which of the following statements is correct (or True)?
A: Lysophosphatidylcholine is choline where the #1 Fatty acid has been hydrolyzed by an enzyme.
B: Phosphotidylinositol 4,5bisphosphate is hydrolyzed into diacylglycerol (DAG) and inositol phosphate (IP) which act as secondary messengers.
C: Cholesterol synthesis starts with 3 moles of AcetylCoA that condense to form HMG CoA (3-hydroxy-3- methylglutaryl CoA).
D: Gangliosides are glycosphingolipids containing Neuraminic acid (NeuAc) and is present in nervous tissues in low concentration.

Answer 95

C

Question 96

Which of the following statements is incorrect (or False)?
A: Ketone bodies are formed in hepatic mitochondria when there is a high rate of fatty acid oxidation.
B: Diseases associated with fatty acid oxidation lead to hyperglycemia and hypoketonemia.
C: Fatty acid oxidation in mitochondria leads to the generation of large quantities of ATP by beta oxidation process. D: Ketosis is mild in starvation but severe in diabetes mellitus and ruminant ketosis.

Answer 96

B

Question 97

Which of the following statements is incorrect (or False)?
A: Lipogenesis is regulated at the AcetylCoA carboxylase step by allosteric modifiers.
B: Lipogenesis is carried out by one enzyme system: Fatty acid synthase.
C: Biosynthesis of unsaturated fatty acids is achieved by desaturase and elongase enzymes.
D: Higher animals have d-4,d-5, d-6 and d-9 desaturases and cannot introduce a new double bond beyond d-9 of fatty acid.

Answer 97

B

Question 98

Which of the following statements is incorrect (or False)?
A: Cystolic Thiolase catalyzes the condensation of two moles of acetylCoA into acetoacetylCoA.
B: HMG-CoA synthase catalyzes the condensation of AcetoacetylCoA with another mole of AcetoAcetylCoA to form HMG CoA.
C: HMG CoA lyase catalyzes the removal of AcetylCoA from HMGCoA.
D: Cholesterol synthesis is regulated by HMG CoA reductase.

Answer 98

B

Question 99

Which of the following statements is incorrect (or False)?
A: Leukotrienes and lipoxins are formed by the COX pathway. B: Group III Leukotrienes are formed from Eicosapentaenoate. C: Group II prostanoids are formed from Eicosatetraenoate. D: Group I Thromboxases are formed from Eicosatrienoate.

Answer 99

A

Question 100

Which of the following statements is incorrect (or False)?
A: Citrate lyase hydrolyzes citrate to Malate and AcetylCoA.
B: AcetylCoA is also regulated by insulin, glucagon and epinephrine.
C: Pyruvate dehydrogenase is also regulated by AcylCoA.
D: Microsomal elongase system extends the length of a growing fatty acid chain by 2 carbons each time.



Answer 100

A