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BioC 6011 F07
Exam 2
Name______________________
1) Fructose can cyclize to (a)
a) pyranose ring
b) furanose ring
c) both pyranose and furanose ring forms *
d) all of the above
c) None of the above
2) The cyclic form of sugars
a) has one more chiral center (the anomeric cardon) than the open-chain form *
b) loses a chiral center compared to the open-chain form
c) is not usually found in nature
d) can have two possible forms, designated R and S
3) Epimers are
a) stereoisomers that differ from each other in their configuration at two or more
carbon atoms
b) stereoisomers that differ from each other in their configuration at a single *
carbon atom
c) the α and β forms of cyclic sugars
d) two related compounds, pyran and furan
4) In a Fischer projection, which carbon determines whether the sugar is the D- or the Lisomer?
a) highest numbered carbon atom
b) lowest numbered asymmetric carbon atom
c) lowest numbered carbon atom
d) highest numbered asymmetric carbon atom *
5) Which of the following molecules is a disaccharide?
a) glucose
b) lactose
c) fructose
d) galactose
6) Glycoproteins
a) are involved in the metabolism of sugars
b) are proteins to which sugars are covalently bonded *
c) occur in the bloodstream of diabetics
d) have not been found in nature, nut have been synthesized in the laboratory
7) Blood typing depends on
a) the nature of the oligosaccharide portion of the glycoproteins on the surface of
red blood cells *
b) the presence of a polysaccharide coating on the red blood cells
c) the presence of a polysaccharide coating on white blood cells
d) the addition of sucrose to blood before storage
8) A pyranose is a sugar that
a) contains a five-membered ring as part of its cyclic structure
b) contains a six-membered ring as part of its cyclic structure *
c) is a five-carbon open-chain sugar
d) is a six-carbon open-chain sugar
9) A glycosidic linkage is chemically
a) an ester
b) an aldehyde
c) a ketone
d) none of the above *
10) Glycolysis
a) does not require O2 to generate energy *
b) an aldehyde
c) a ketone
d) none of the above
11) The phosphorylation of glucose to glucose 6-phosphate
a) is so strongly exergonic that it does not require a catalyst
b) is an exergonis reaction not coupled to any other reaction
c) is an endergonic reaction that takes place because it is coupled to the exergonis
hydrolysis of ATP *
d) is an exergonic reaction that is coupled to the endergonic hydrolysis of ATP
12) The reduced form of flavin adenine dinucleotide is
a) FADH
b) FAD
c) FADH+
d) FADH2 *
e) none of the above
13) Which of the following is the electron donor used for reductive biosynthesis
a) NADH
b) NADPH *
c) FADH2
d) CoASH
e) ATP
14) The reaction of fructose 1, 6-bisphosphate to give glyceraldehyde 3-phosphate and
and dihydroxyaceetone phosphate is an example of
a) a reverse aldol condensation *
b) hydrolysis
c) oxidation
d) dehydration
15) The equilibrium for isomerization of dihydroxyacetone phosphate to glyceraldehyde3-phosphate is favored because
a) the standard free energy is negative
b) glyceraldehyde-3-phosphate is being continuously drained off for the
subsequent reaction in the gly colytic pathway *
c) the value of the equilibrium constant favors the reaction
d) it is driven by the hydrolysis of ATP
16) Which of the following statements is not true for the conversion of glyceraldehyde 3phosphate to 1, 3-biophosphoglycerate?
a) it requires ATP
b) it is an oxidative process
c) it generates a high-energy compound
d) it is catalyzed by a dehydrogenase *
17) The conversion of 1, 3-bisphoglycerate to 3-phosphoglycerate is
a) a strongly endergonic reaction
b) accompanied by a dehydration of molecule
c) one of the reactions of glycolysis in which ATP is produced *
d) a side reaction not part of the main pathway of glycolysis
18) The reduction of pyruvate to lactate
a) allows for recycling of NAD+ *
b) is the process that aids in the recovery of sore muscles after exercise
c) is accompanied by phosphorylation of ADP
d) does not occur in aerobic organisms
19) The isomerization of dihydroxyacetone phosphate to give glyceraldehyde 3phosphate
a) is catalyzed by the enzyme triosephosphate isomerase *
b) requires several enzymes
c) requires coenzymes A
d) requires thiamine pyrophosphate
20) In the conversion of the glyceraldehyde-3-phosphate to 1, 3-bisphosphoglycerate
a) an alcohol group is phosphorylated
b) an alcohol is oxidized to an aldehyde
c) an alcohol is oxidized to a cardoxylic acid
d) an aldehyde is oxidized to a cardoxylic acid *
21) Which of the following exercise(s) allosteric control in the reaction of
phosphofructokinase?
a) ATP
b) fructose 2, 6-bisphosphate
c) both of the above *
d) neither of the above
22) Glycogen is mainly found in
a) liver and muscle *
b) liver and brain
c) muscle and brain
d) liver, muscle, and brain
23) The enzyme glycogen phosphorylase catalyzes a reaction in
a) the formation of glycogen from glucose
b) glycogen breakdown *
c) gluconeogenesis
d) the pentose phosphate pathway
24) The compound uridine diphosphate glucose (UDPG) plays a role in
a) glycogen breackdown
b) glycogen synthesis *
c) glycolysis
d) gluconeogenesis
25) Gluconeogenesis is the synthesis of
a) glucose from non-carbohydrate precursors *
b) glycogen from glucose
c) pyruvate from glucose
d) fatty acids from glucose
26) In gluconeogensis, the initial reaction converts pyruvate to
a) oxaloacetate *
b) acetyl-CoA
c) phosphoenolpyruvate
d) lactate
27) The initial phase of the pentose phosphate pathway does not include
a) release of a CO2 molecule
b) production of two molecules of NADPH
c) production of ribulose-5-phosphate by an oxidative decarboxylation of 6phosphogluconate
d) the reduction of glucose-6-phosphate *
28) The oxidative reactions of the pentose phosphate pathway
a) produce NADPH rather than NADH *
b) require biotin
c) require coenzyme A
d) require thiamine pyrophosphate
29) Which enzymes in the citric acid cycle catalyze oxidative decarboxylation reactions?
a) isocitrate dehydrogenase and the α-ketoglutarate dehydrogenase complex *
b) aconitase and succinate dehydrogenase
c) the α-ketoglutarate dehydrogenase complex and succinate thiokinase
d) fumarase and succinate dehydrogenase
30) Which coenzyme listed below is not associated with the pyruvate dehydrogenase
complex?
a) thiamine pyrophosphate
b) lipoic acid
c) biotin *
d) NAD+
31) The only membrane-bound enzyme in the citric acid cycle is
a) aconitase
b) α-ketoglutarate dehydrogenase complex
c) malate dehydrogenase
d) succinate dehydrogenase *
32) When acetyl-CoA reacts with oxaloacetate to form citrate
a) a new carbon-carbon bond is formed *
b) an oxidative decardboxylation reaction takes place
c) a dehydration reaction takes place
d) a rearrangement takes place
33) In the conversion of succinyl-CoA to succinate, GTP is produced from GDP in a
reaction in which the source of the added phosphate is
a) ATP
b) ADP
c) phosphenolpyruvate
d) inorganic phosphate ion *
34) A unique feature of the glyoxylate cycle is that it allows the organisms that psses this
pathway to
a) produce fats from carbohydrates
b) produce carbohydrates from fats *
c) convert acetyl-CoA to pyruvate
d) do all of the above
35) The citric acid cycle is considered part of aerobic metabolism even though oxygen
does not appear explicitly in any reaction because
a) the NADH and FADH2 produced are reoxidized in the electron transport chain
linked to oxygen *
b) the reoxidation of NADH and FADH2 leads to the production of considerable
quantities of ATP
c) it takes place in the mitochondrion
d) it contains oxidation reactions
36) What is substrate level phosphorylation?
a) phosphorylation of AMP by ATP
b) ATP synthesis when the phosphate donor is a substrate with high phosphoryl
transfer potential *
c) phosphorylation of glycolytic intermediates
d) phosphorylation of ATP couples to an ion gradient
e) ATP and AMP synthesis from two molecules of ADP
37) What enzyme(s) is (are) responsible for the following reaction?
Pyruvate + CoA + NAD+ → acetyl CoA + NADH + H+ + CO2
a) acetyl CoA synthetase
d) a and b
b) pyruvate decarboxylase
e) a, b and c
c) pyruvate dehydrogenase complex*
38) What type of gradient is critical to ATP formation by oxidative phosphorylation?
a) sodium ion
b) chloride ion
c) proton *
d) potassium ion
e) none of the above
39) Which of the following does not participate in, nor is a component of, the electrontransport chain?
a) coenzyme A
b) non-heme, iron-sulfur proteins
c) coenzyme Q
d) cytochrome C1 *
e) NADH
40) Coenzyme Q is also called
a) NADH
b) oxidoreductase
c) ubiquinone *
d) all of the above
e) none of the above
41) In the proteins these amino acids residues usually complex to the iron-sulfur clusters
a) gly
b) arg
c) cys *
d) all of the above
e) none of the above
42) Oxidative phosphorylation is coupled to electron transport in
a) complexes II, III, IV
b) complexes I, III, IV *
c) complexes I, II, III
d) all four respiratory complexes
43) An alternative mode of entry into the electron transport chain is the oxidation of
a) malate to oxalosuccinate
b) succinate to fumarate *
c) isocitrate to α-ketoglutarate
d) α-ketoglutarate to succinyl-CoA
44) Advantages of fatty acids as primary energy storage molecules include all of these
points except
a) they are more reduced than cardohydrates
b) they are hydrophobic in nature and can pack more efficiently in fat storage
cells
c) they are more readily available for immediate metabolis needs *
d) they contain more energy per gram than carbohydrates
45) The one incorrect statement below about the activation of fatty acids is
a) it involves the formation of a high energy thiol ester bond
b) activation is accompanied by hydrolysis of ATP to ADP and Pi *
c) an acyl-adenylate intermediate is formed
d) hydrolysis of ATP produces AMP and PPi, with further hydrolysis of PPi to
drive the reaction to completion
46) The unsaturated fatty acids that are intermediates in the β-oxidation cycle of fatty
acids produce
a) two moles of NADH
b) two moles of FADH2
c) one mole each of NADH and FADH2 *
d) two moles of ATP
47) The unsaturated fatty acids that are intermediates in the β-oxidation cycle have what
orientation around the double bond?
a) the cis orientation
b) the trans orientation *
c) can have either orientation
d) the orientation is not known
48) The processing of one molecule of stearic acid (18 carbons) by β-oxidation
a) requires 8 cycles of β-oxidation and produces 9 molecules of acetyl-CoA *
b) requires 8cycles of β-oxidation and produces 8 molecules of acetyl-CoA
c) requires 9 cycles of β-oxidation and produces 8 molecules of acetyl-CoA
d) requires 9 cycles of β-oxidation and produces 9 molecules of acetyl-CoA
49) A major difference between the anabolism and catabolism of fatty acids is that
a) biotin is required for oxidation of fatty acids but not for anabolism
b) NADPH is required for anabolism of fatty acids and not for catabolism *
c) anabolism takes place in the mitochondria while catabolism takes place in the
mitochondrial matrix
d) acetyl-CoA is not required for anabolism
50) The addition of two-carbon units to a growing fatty acid chain is directly driven by
a) reduction of NADP+
b) oxidation of NADPH
c) decarboxylation of malonyl-CoA *
D) Hydrolysis of ATP