BioC6011 Fall06 exam II
1) In ATP, the adenine is linked to the ribose by a ___ bond.
A. o-glycosidic
B. glycosidic
C.  N-glycosidic
D.  N-glycosidic *
E. disulfide
2) Lactose contains:
A. galactose linked to glucose with a -1-4 linkage.
B. galactose linked to glucose with a  -1-4 linkage. *
C. glucose linked to galactose with a -1-4 linkage.
D. glucose linked to galactose with a  -1-4 linkage.
E. glucose linked to fructose with a -1-4 linkage.
3) Hydrolysis of ATP results in a release of free energy of:
A. 7.3 Kcal/mole *
B. 1.2 Kcal/mole
C. 5.1 Kcal/mole
D. 13.9 Kcal/mole
E. 20.5 Kcal/mole
4) Glycosidic bonds
A. Connect sugar molecules in both linear and branches of complex carbohydrates. *
B. Only connect carbon-1 of one sugar to carbon-4 of another.
C. Destroy the asymmetric character of the participating carbons
D. Only connect carbon-1 of one sugar to carbon-6 of another
E. Are not found commonly in sugars
5) Glycoproteins
A. contain oligosaccharides linked to the side chain of lysine or arginines residues
B. contain oligosaccharides linked to the side chain of asparagines, serine or
threonine residues *
C. contain linear oligosaccharides with a terminal glucose residue
D. bind to liver cell-surface receptors that recognize sialic acid residues
E. are mostly cytoplasmic proteins
6) What generates more energy?
A. oxidation of a more reduced carbon atom to CO2. *
B. oxidation of a less reduced carbon atom to CO2.
C. a and b generate the same amount of energy.
D. neither a nor b generates any energy.
7) Complete the statement: The furanose form of fructose is generated by formation of a
hemiketal involving the attack of the hydroxyl group on carbon ____ with carbon ____
A. 5, 2 *
B. 2, 5
C. 2, 6
D. 6, 2
E. 1, 6
8) Triglycerides (are):
A. insoluble in water.
B. A six-fold more weight-efficient store of energy than glycogen.
C. require lipases for degradation.
D. A + B
E. A + B + C *
9) Reactions and processes that break down material and transform fuels into cellular
energy are referred to as:
A. Anabolic
B. Catabolic*
C. Intermediary metabolism
D. Anaplerotic
E. None of the above
10) The following does NOT contribute to the high phosphoryl transfer potential of ATP:
A. Resonance stabilization
B. Solvation
C. Electrostatic repulsion
D. The sugar moiety *
E. All of the above contribute to the high phosphoryl transfer potential
11) During catabolic processes, the oxidation of energy rich molecules often results in the
reduction of NAD+ to NADH. What comparable molecule is the most commonly used
reductant for reductive steps in anabolic processes?
A. FAD
B. NADPH *
C. Coenzyme A
D. ATP
F. None of the above
12) The
A.
B.
C.
D.
E.
major roles for fatty acids are as:
components of membrane lipids.
hydrophobic modifiers of proteins targeted to membrane.
fuel molecules.
precusors for some hormones.
all of the above. *
13) Blood group antigen (ABO) are _______ on the outside of a red blood cell
A. Glycoproteins that differ in the protein moiety.
B. Glycolipids that differ in the carbohydrate moiety. *
C. Membrane proteins that differ in state of phosphorylation.
D. The protein moieties of a glycoproteins that are encoded by different genes.
14) During anaerobic metabolism of glucose in muscle, there is a net production in the
cytosol of lactate and
A. NAD+
B. NADH
C. CO2
D. ATP *
E. FADH2
15) The committed step of the glycolytic pathway is catalyzed by
A. hexokinase
B. phosphofructokinase *
C. aldolase
D. glycerol 6-phosphate dehydrogenase.
E. pyruvate kinase
16). An enzyme in glycolysis that catalyzes a reversible reaction and generates a molecule
with high phosphoryl group transfer potential is:
A. Hexokinase
B. Aldolase
C. Phosphofructokinase
D. Glyceraldehyde 3-phosphate dehydrogenase *
E. Phosphoglucoisomerase
17) During intense exercise, which of the following accumulates in muscle?
A. Glucose
B. Ethanol
C. Lactate *
D. Glycogen
E. None of the above
18) The branch point molecule after glycolysis is
A. glucose-6-phosphate
B. pyruvate *
C. glyceraldehydes-3-phosphate
D. phosphoenolpyruvate
E. None of the above
19) Although glucose is the major sugar degraded by the glycolytic pathway, other sugars
such as galactose and fructose are also often present. These sugars
A. Cannot be metabolized by the glycolytic pathway.
B. Must first be converted to glucose in order to be metabolized.
C. Are metabolized by the glycolytic pathway by conversion to intermediates in the
Pathway. *
D. Are oxidized to carbon dioxide and water and energy is released without involving
the glycolytic pathway
E. None of the above
20) A yeast mutant has a defective triose phosphate isomerase that is totally inactive.
Which of the following would you expect if this yeast mutant were grown under anaerobic
conditions? (Ignore the amount of ATP consumed in stage of glycolysis.)
A. The ATP produced/glucose degraded ratio would be the same as for normal cells
B. The ATP produced/glucose degraded ratio would be one-half that of normal cells *
C. The ATP produced/glucose degraded ratio would be zero.
D. The ATP produced/glucose degraded ratio would be twice that of a normal cells..
21) The processes of gluconeogenesis and glycolysis are reciprocally regulated. This means
that
A. Molecules that inhibit (or activate) one process often inhibit (or activate) the other
in the same manner.
B. Molecules that inhibit (or activate) one process often have the opposite effect on
the other. *
C. Different sets of molecules are involved in the regulation of each pathway.
D. The pathways alternate in a regular manner.
E. Regulation occurs only at the transcriptional level for these processes.
22) What product of contracting muscle is used by the liver as starting material for
gluconeogenesis?
A. Lactate *
B. Oxaloacetate
C. Glycerol
D. Fumarate
E. Aconitate
23) In glycolysis, the conversion of fructose 1,6-bisphosphate to the immediate product(s)
involves
a. carbon-carbon bond cleavage. *
b. dehydration.
c. phosphoryl transfer.
d. aldose-ketose isomerization.
e. dephosphorylation.
24) All of the following statements concerning the citric acid cycle are true EXCEPT
A. The cycle starts with the four-carbon compound oxaloacetate, adds two carbons
from acetyl-CoA, stepwise loses two carbons as CO2, and regenerated the fourcarbon compound oxaloacetate.
B. For each molecule of glucose metabolized, two molecules of a high phosphoryl
donor potential are formed.
C. Regulation of the enzyme activity of isocitrate dehydrogenase and –ketoglutarate
dehydrogenase control this cycle.
D. The pyruvate that enters this cycle is generated by glycolysis or protein
catabolism
E. The enzymes involved in the citric acid cycle are found in the cytosol. *
25) In the reaction mechanism for the oxidative decarboxylation of pyruvate, which cofactor
is required for the decarboxylation step?
A. Thiamine pyrophosphate *
B. Lipoic acid
C. FAD+
D. NAD+
E. Biotin
26) After complete metabolism of one molecule of glucose to carbon dioxide via the citric
acid cycle, what will be the net change in the amount of oxaloacetate?
A. Increased by two molecules
B. Increased by one molecule
C. Unchanged *
D. Decreased by one molecule
E. Decreased by two molecules
27) A generic name of all the enzymes that catalyze the oxidation reactions in the citric acid
cycle is
A. oxidase.
B. reductase.
C. dehydratase.
D.synthase.
E. dehydrogenase *
28) How many ATP’s are gained from the complete oxidation of one glucose molecule.
A. 10
B. 12
C. 30 *
D. 36
E. 42
29) The citric acid cycle is a hub of energy transformation. Which citric acid cycle enzyme
produces GTP by substrate level phosphorylation?
A. triose phosphate isomerase
B. aldolase
C. glyceraldehydes-3- phosphate dehydrogenase
D. succinyl CoA synthetase *
E. enolase
30) Identify the TCA cycle intermediate that condenses with acetyl CoA to form citrate.
A. malate
B. succinate
C. ketoglutarate
D. fumarate
E. oxalacetate *
31) In the reaction catalyzed by the pyruvate dehydrogenase complex, the two carbons
constituting the acetyl group are
A. Transferred directly to the biotin cofactor.
B. Transferred to the lipoamide by an earlier intermediate in the process. *
C. Oxidized by NAD while attached to the lipoamide.
D. Equally divided between oxaloacetate and succinate
32) Which member of the electron transport chain is also called Coenzyme Q?
A. ubiquitin
B. ubiquinone *
C. flavin mononucleotide
D. cytochrome c
E. nicotinamide adenine dinucleotide
33) Proton flow through the ATP synthase enzyme
A. provides the energy for adding a phosphate to ADP to make ATP *
B. results in an equilibration of protons inside and outside of the mitochrondria.
C. produces local pH changes in the active site which alter the equilibrium constant
for the reaction
D. Activates electron transport in the opposite direction
E. None of the above
34) Glycolysis occurs in the cytoplasm. The electrons from the NADH generated during
glycolysis
A. enter the mitochondrial electron chain directly as NADH freely enters the
mitochondria
B. cannot be used by the mitochondrial electron transport chain as NADH cannot
enter the mitochondria
C. may enter the electron transport chain by using a shuttle system. *
D. are transferred to water molecules in the cytoplasm.
35) Degradation (catabolism) of unsaturated fatty acids involves:
A. an additional reductase
B. an additional isomerase
C. both an additional reductase and isomerase for all unsaturated fatty acids.
D. only an additional reductase for some unsaturated fatty acids and only an
isomerase for other unsaturated fatty acids
E. an additional reductase and an isomerase for some unsaturated fatty acids and only
an isomerase for other unsaturated fatty acids. *
36) All of the following statements about fatty acid synthesis are true EXCEPT:
A. Fatty acid synthesis takes place in the mitochondria while fatty acid breakdown
(catabolism) takes place in the cytosol. *
B. Fatty acid synthesis involves and acyl carrier protein and the additions of two
carbons derived from acetyl CoA in each step of the synthesis.
C. The ultimate source for the carbons for fatty acids synthesis is glucose.
D. Fatty acid synthesis is not the simple reversal of -oxidation used for catabolism of
fatty acids.
E. The committed step in fatty acids synthesis is the formation of malonyl CoA from
acetyl CoA and carbon dioxide.
37) Animals are not capable of converting fatty acids into glucose because
A. They cannot convert pyruvate to oxaloacetate by carboxylation
B. They cannot convert pyruvate to phosphoenol pyruvate
C. They cannot convert acetyl-Coenzyme A into pyruvate or oxaloacetate to initiate
the gluconeogenesis pathway *
D. Fatty acid degradation does not produce sufficient energy in the form of ATP to
drive gluconeogenesis
E. none of the above
38) Which of the following is NOT a difference in the pathways by which fatty acids are
degraded and synthesized?
A. the location of the process
B. the involvement of a different nicotinamide cofactor
C. the molecule to which the chain being synthesized or degraded is attached
D. the presence or absence of a double bond
E. all of the above are different in fatty acid synthesis and degradation *
39) In the breakdown of glycogen, the initial product formed is
A. glucose-1-phosphate *
B. glucose-2-phosphate
C. glucose-4-phosphate
D. glucose-5-phosphate
E. glucose-6-phosphate
40) Which of the following is an essential fatty acid?
A. malonic acid
B. palmitic acid
C. linolenic acid *
D. oleic acid
E. arachidonic acid
41) During oxidative phophorylation, the cytochrome that passes electrons directly to
oxygen is
A. the cytochrome a/a*
B. cytochrome b
C. cytochrome c
D. cytochrome c1
E. cytochrome c2
42) Most signal molecules (like insulin)
A.
easily diffuse through the membrane and bind to a receptor in the cytoplasm.
B.
bind to membrane receptors and transmit information across a membrane
without traversing the membrane. *
C.
carry out functions in the nucleus after binding to a receptor in the cell
membrane.
D.
a and c.
E.
a, b, and c.
43) In
A.
B.
C.
D.
E.
the electron transport chain, two soluble carriers are used. They are
cytochrome a1/a3
CoQ and cytochrome c *
CoQ and cytochrome b
Cytochrome c1 and cytochrome d
None of the above.
44) Which of the following enzymes are used in glconeogenesis but not glycolysis
A. pyruvate carboxykinase
B. phophoenolylpyravate carboxykinase
C. Fructose-1,6-bisphosphatase
D. Glucose-6-phosphotase
F. All of the above *
45) An example of an isomerization reaction would be
A.
the conversion of succinate to fumarate using FAD.
B.
the addition of carbon dioxide to pyruvate to form oxaloacetate.
C.
the conversion of citrate to isocitrate. *
D.
the hydrolysis of a peptide bond.
E.
none of the above.
46) Some of the mechanisms by which catalytic activity is controlled in enzymes
involve.
A.
allosteric control
D.
a and c
B.
feedback inhibition
E.
a, b, and c *
C.
covalent modification
47) Which of the following is an example of an oxidation/reduction reaction?
A.
-
O2C CH2 CH2 CO2-
H
+ FAD
C C
-
O2C
B.
O
-
O2CCH2CCO2- + ADP + Pi
+ CO2 + ATP
CO2-
CO2H2N C H
H C NH2
CH3
D.
E.
*
O
CH3CCO2C.
CO2
+ FADH2
H
Ala-Ser + H20 ---- Ala + Ser
None of the above.
CH3
48) What two 3-carbon molecules are generated by the cleavage of fructose-1,6bisphosphate?
A.
glyceraldehyde-3-phosphate and 3-phosphoglycerate
B.
glyceraldehyde-3-phosphate and dihydroxyacetone phosphate *
C.
pyruvate and phosphoenolpyruvate
D.
enolate and 2-phosphoglycerate
E.
glyceraldehyde-3-phosphate and pyruvate
49) Phosphofructase kinase is
A. activated by ATP
B. inhibited by ATP *
C. not regulated by ATP
D. not regulated at all
50) 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 coupled to an ion gradient
E.
ATP and AMP synthesis from two molecules of ADP