BCH 400/600
Spring 2002
Exam 3
March 25
Name_________________________
For Questions 1 thru 25, mark the correct answer on the Scantron answer sheet and the exam.
There will be only one correct answer for each question.
Multiple Choice (2 points each)
1) Which of the following is an acyl-lipid?
a. ubiquinone
b. chlorophyll
c. phosphatidylcholine
d. steroids
e. none of the above
2) Which of the following is not a property a lipid?
a. primarily non-polar compounds
b. highly soluble in non-polar organic solvents
c. amphipathic molecules
d. highly soluble in water
e. None of the above
3) A fatty acid designated 20:1Δ15 has a double bond located________________________.
a. between carbons 14 and 15 of the fatty acid counting from the carboxyl group.
b. between carbons 15 and 16 of the fatty acid counting from the carboxyl
group.
c. between carbons 14 and 15 of the fatty acid counting from the last methyl group.
d. between carbons 15 and 16 of the fatty acid counting from the last methyl group.
e. None of the above
4) Within a membrane bilayer, lipids and membrane associated proteins ______________.
a. can freely diffuse across the lipid bilayer.
b. freely exchange with aqueous cell fractions.
c. are fixed in position.
d. have free lateral movement.
e. None of the above
5) Which of the following types of membrane transporters do not show saturable kinetics?
a. passive (facilitative) transporters
b. active transporters
c. pores/channels
d. a and b
e. a and c
6) Factors influencing the phase transition temperature of a lipid bilayer are _______.
a. the length of the fatty acids attached to the phospholipids.
b. the number of double bonds in the fatty acids attached to the phospholipids.
c. the amount of cholesterol present.
d. All of the above.
e. None of the above.
7) Which of the following are factors related to the high yield of energy derived from the
cleavage of the phosphoanhydride linkages of ATP?
a. electrostatic repulsions between negatively charged oxygens.
b. entropy effects.
c. increased resonance stability of the products.
d. a high phosphoryl-group transfer potential.
e. All of the above.
8) The ΔGo’hydrolysis for ATP to ADP and Pi = -32 kJ/mole and the ΔGo’hydrolysis for
phosphoenolpyruvate to pyruvate and Pi = -62 kJ/mole. Based on this information, ATP
will serve as a(n) __________ in a phosphoryl-transfer reaction with
phosphoenolpyruvate.
a. donor
b. acceptor
c. equal
d. none of the above
e. all of the above
9) In the steady state model of metabolism, where A −> B −> C −> D, _________________.
a. the concentration of B and C are at equilbrium.
b. the concentration of B and C is constant because the rate of its formation is
equal to the rate of their utilization.
c. the concentration of B and C are decreased because the rate of their formation is
less than the rate of their utilization.
d. the concentration of B and C are increased because the rate of their formation is
higher than the rate of their utilization.
e. None of the above.
10) Under physiological conditions, the ΔG of a reaction_____________________________.
a. is always equal to ΔGo’.
b. is always dependent on the actual concentration of reactants and products.
c. is always near equilibrium.
d. is always metabolically irreversible.
e. None of the above.
11) Glycolysis can be described as ____________________________________.
a. an anabolic process.
b. a catabolic process.
c. None of the above.
12) In a linear organized metabolic pathway_________________________.
a. the same set of enzymes are used to synthesize different pathway intermediates.
b. the pathway intermediates are recycled.
c. the product of one reaction serves as the substrate for the subsequent
reaction.
d. the regulation always occurs at the last step in the pathway.
e. None of the above.
13) The Pasteur Effect refers to the observation that within the same organism rates of
glycolysis are ___________ under anaerobic conditions than under aerobic conditions.
a. lower
b. higher
c. the same
d. none of the above
14) Under anaerobic conditions pyruvate can be converted to
a. acetyl-CoA.
b. lactate.
c. ethanol.
d. a and b
e. b and c
15) Lactate dehydrogenase recycles NADH back to NAD+ to provide an oxidizing agent for
the glycolytic step catalyzed by which enzyme?
a. hexokinase
b. phosphoglycerate mutase
c. glyceraldehyde 3-phosphate dehydrogenase
d. triose phosphate isomerase.
e. phosphofructokinase.
16) In the reaction catalyzed by pyruvate dehydrogenase what coenzyme transfers the 2
carbon unit from the E1 subunit to Coenzyme A?
a. thiamin pyrophosphate
b. NAD+
c.
FAD+
d. Dihydrolipoamide
e. None of the above.
17) A symport transports ___________________.
a. a single molecule across a membrane.
b. two molecules in the same direction across a membrane.
c. two molecules in the opposite directions across a membrane.
d. None of the above.
18) The purpose of the Cori Cycle is to_______________________.
a. regenerate glucose in the liver from ethanol produced in the muscle tissues under
anaerobic conditions.
b. regenerate glucose in the liver from lactic acid produced in the muscle tissues
under anaerobic conditions.
c. regenerate lactic acid in the liver from ethanol produced in the muscle tissues
under anaerobic conditions.
d. regenerate glucose in the liver from galactose produced in the muscle tissues
under anaerobic conditions.
e. None of the above
19) Lactose intolerance is___________________________________________.
a. rarely observed in young children.
b. a normal developmental change in metabolism.
c. rarely observed in people of Northern European descent.
d. causes discomfort due to gas and diarrhea.
e. All of the above.
20) Tay Sach Disease and Niemann-Pick Diesease are inherited metabolic disorders related
to____________.
a. the inability to break down galactose.
b. the inability to digest lactose.
c. the inability to degrade sphingolipids.
d. the inability to remember all of the steps in glycolysis
e. None of the above.
QUESTIONS (21 THRU 25) MATCH THE FUNCTION WITH THE ENZYME (2
POINTS EACH)
a.
b.
c.
d.
e.
Generates GTP
Donates electrons directly to electron transport chain
Converts pyruvate to acetyl-CoA
Catalyzes an oxidative decarboxylation (generates NADH and CO2)
Point at which acetyl-CoA enters citric acid (TCA) cycle
21) ____B___ Succinate dehydrogenase
22) _____A___ Succinyl-CoA synthase
23) ____D____ Isocitrate dehydrogenase
24) _____E___ Citrate synthase
25) _____C___ Pyruvate dehydrogenase
26) (10 points) Draw the structure of phosphatidylserine with a palmitic acid and a linolenic acid
attached to the glycerol backbone.
27) (10 points) Although the Citric Acid (TCA) Cycle was primarily introduced in lecture as a
catabolic pathway, this pathway is also involved in a number of anabolic processes. List three
classes of unrelated compounds (i.e if you list proteins and amino acids that counts as only one)
that are synthesized from TCA cycle intermediates and the corresponding TCA intermediate
from which they are derived. Briefly explain why anaplerotic reactions are important to the
TCA Cycle in relationship to these anabolic processes.
28) (20 points) The next page contains the structures of all of the intermediates of glycolysis
from glucose to pyruvate. You need to do the following:
A. Draw a unidirectional arrow (Æ) between the substrate and the product of all
irreversible reactions.
B. Draw a bidirectional arrow (ÅÆ) between the substrate and the product of all
reversible reactions.
C. For each step that consumes ATP, designate it as follows:
ATP
ADP
Reactant
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
D. For each step that generates ATP, designate it as follows:
ADP
Reactant
ATP
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
E. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
reaction substrate and the name of the reaction product next to the correct
structure.
F. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
enzyme.
G. For the 3 regulated enzymatic reactions of glycolysis , list all allosteric activators
and allosteric inhibitors involved in the regulation of these reactions. You need to
make it clear what are the inhibitors and what are the activators.
Questions 29 thru 33. (2 points each) Match the specific component from the signal transduction
pathway above with its function below.
Adenyl
cylase
Epinephrine
receptor
cAMP
Protein Kinase A
(inactive)
Protein Kinase A
(active)
cellular response
29) ____Epinephrine__________ External stimulus (First messenger)
30) ______G-protein__________ Transducer
31) ______Adenylate cyclase effector enzyme
32) _______cAMP__________________ Second messenger
33) ___________Protein Kinase A______________ Cytoplasmic effector enzyme.
EXTRA CREDIT (5 POINTS)
Describe how the Kcat (turnover number) of the G-protein GTPase activity relates to the duration
of the signaling response. Why would a G-protein with a higher Kcat or lower Kcat be
undesirable in a signaling pathway?
CHO
CHO
CH2OH
H
C
OH
C
O
HO
C
H
HO
C
H
OH
H
C
OH
H
C
OH
OH
H
C
OH
H
C
OH
H
C
OH
HO
C
H
H
C
H
C
CH2OH
CH2OPO3--
CH2OPO3--
CH2OPO3-C
O
HO
C
H
H
C
OH
H
C
OH
CH2OPO3-O
H
H
C
CH2OPO3--
C
C
OH
O
CH2OH
CH2OPO3--
O
--O3PO
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OPO3--
CH2OH
O
-O
C
C
OPO3--
CH2
O
-O
C
C
O
CH3
BCH 400/600
Spring 2003
Exam 3
March 28
Name_________________________
Multiple Choice (2 points each)
26) Under aerobic conditions pyruvate is converted to
a. acetyl-CoA.
b. lactate.
c. ethanol.
d. a and b
e. b and c
27) The temperature at which a membrane undergoes transition from a liquid crystalline state
to a gel state depends on _______.
a. the length of the fatty acids attached to the phospholipids.
b. the number of double bonds in the fatty acids attached to the phospholipids.
c. the amount of cholesterol present.
d. All of the above.
e. None of the above.
28) Membrane anchored proteins can have acyl groups covalently linked to the protein
through ____________ residues.
a. glycine
b. cysteine
c. serine
d. all of the above
29) Which of the following classes of acyl-lipids is primarily used as a source of stored
energy?
a. phospholipids
b. sphingolpids
c. triacylglycerol
d. cholesterol
e. none of the above
30) An 18 carbon fatty acid that has a double bond located between carbons 9 and 10
(counting from the carboxyl group) is designated as _________.
a. 18:0 Δ 9
b. 18:0 Δ 10
c. 18:1 Δ 9
d. 18:1 Δ 10
31) Flippases _______________
a. are proteins that allow lipid molecules to transverse lipid bilayers
b. are proteins that allow lipid molecules diffuse laterally through a lipid bilayer
c. is the name of a dolphin in a 1960’s TV series.
d. are offensive hand gestures.
32) Which of the following types of membrane transporters show saturable kinetics?
a. passive (facilitative) transporters
b. active transporters
c. pores/channels
d. a and b
e. a and c
33) Which chemical linkage present in ATP give this compound its highest phosphoryl-group
transfer potential
a. Phosphoester linkages
b. Phosphodiester linkages
c. Phosphoanhydride linkages
d. None of the above.
34) A protein that spans a lipid bilayer is referred to as a ____________.
a. peripheral membrane protein
b. a membrane anchored protein
c. an intrinsic membrane protein
d. Bob
35) Which of the following is consistent with the steady state model of metabolism?
a. The concentrations of all pathway intermediates are at equilibrium.
b. The concentrations of pathway intermediates remain constant because the rate of
its formation is equal to the rate of their utilization.
c. The concentrations of pathway intermediates decreases because the rate of their
formation is less than the rate of their utilization.
d. The concentrations of pathway intermediates increase because the rate of their
formation is higher than the rate of their utilization.
e. None of the above.
36) If for a particular enzymatic reaction the mass action ratio (Q) is equal to the equilibrium
constant (Keq ), the reaction will be ____________ .
a. a metabolically irreversible reaction
b. a near equilibrium reversible reaction
c. a energetically unfavorable
d. none of the above
37) The TCA cycle can be described as ____________________________________.
a. an anabolic process.
b. a catabolic process.
c. an amphibolic process (both catabolic and anabolic)
d. None of the above.
38) Under anaerobic conditions, the major reason that pyruvate is converted to lactic acid or
ethanol is ___________.
a. to remove toxic pyruvate
b. to regenerate NAD+ for further rounds of glycolysis
c. to regenerate ADP for further rounds of glycolysis
d. all of the above
39) The process by which glucose is regenerated in the liver from lactic acid produced in the
muscle tissues under anaerobic conditions
a. Pasteur Effect
b. Bohr Cycle
c. Cori Cycle
d. Kreb cycle
e. none of the above
40) In the reaction catalyzed by pyruvate dehydrogenase, which coenzyme plays a role in the
reoxidation of the reduced lipoamide coenzyme?
a. thiamin pyrophosphate
b. FAD+
c. Coenzyme A
d. None of the above.
41) An antiport transports ___________________.
a. a single molecule across a membrane.
b. two molecules in the same direction across a membrane.
c. two molecules in the opposite directions across a membrane.
d. None of the above.
42) __________________ allows organisms like plants and bacteria to utilize acetyl-CoA for
the synthesis of carbohydrates.
a. The Krebs Cycle
b. Glycolysis
c. The Glyoxylate Cycle
d. The Cori Cycle
e. None of the above
43) The TCA cycle enzymes are localized within ___________.
a. the cytosol
b. the mitochondrial matrix
c. the mitochondrial inner membrane
d. the mitochondrial cristae
44) _______ moles of ATP are produced through glycolysis from one mole of glucose to the
formation of two moles of pyruvate.
a. One
b. Two
c. Three
d. Four
45) Which of the following enzymes is not a control point in the TCA cycle?
a. pyruvate dehydrogenase
b. isocitrate dehydrogenase
c. citrate synthase
d. alpha-ketogluturate dehydrogenase
QUESTIONS (21 THRU 25) MATCH THE FUNCTION WITH THE GLYCOLYTIC
ENZYME (2 POINTS EACH) LETTERS CAN BE USED TO ANSWER MORE THAN
ONE QUESTION
f.
g.
h.
i.
j.
Aldolase
Phosphofructokinase-1
Glyceraldehydes-3-phosphate dehydrogenase
Pyruvate kinase
hexokinase
46) ________ Allosterically activated by fructose-2,6-bisphosphate
47) ________ First committed step in glycolysis
48) ________ Converts six carbon compound to two three carbon compounds
49) ________ NADH is one of the products of the reaction
50) ________ Generates ATP through substrate level phosphorylation.
26) (10 points) Draw the structure of phosphatidylcholine with two oleic acid groups attached to
the glycerol backbone.
Answer the following questions based on the diagram below:
51) (4 points) Write the names of the intermediates labeled “A” and “B”
52) (4 points) Name the enzymes and list the corresponding numbers of the three reactions
where an oxidative decarboxylation occurs.
53) (4 points) Name the enzyme and list the corresponding number that designates the
enzymatic step that donates electrons directly to the mitochondrial electron transport
chain
54) (4 points) List the allosteric activators of pyruvate dehydrogenase.
55) (4 points) Name the enzyme and list the corresponding number that designate the
enzymatic step where a substrate level phosphorylation
28) (20 points) The next page contains the structures of all of the intermediates of glycolysis
from glucose to pyruvate. You need to do the following:
A. Draw a unidirectional arrow (Æ) between the substrate and the product of all
irreversible reactions.
B. Draw a bidirectional arrow (ÅÆ) between the substrate and the product of all
reversible reactions.
C. For each step that consumes ATP, designate it as follows:
ATP
ADP
Reactant
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
D. For each step that generates ATP, designate it as follows:
ADP
Reactant
ATP
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
E. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
reaction substrate and the name of the reaction product next to the correct
structure.
F. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
enzyme.
EXTRA CREDIT (10 points) In the space below describe how glucagon effects the flux through
glycolysis. Describe the specific enzyme activities that are up or down regulated by glucagon.
CHO
CHO
CH2OH
H
C
OH
C
O
HO
C
H
HO
C
H
OH
H
C
OH
H
C
OH
OH
H
C
OH
H
C
OH
H
C
OH
HO
C
H
H
C
H
C
CH2OH
CH2OPO3--
CH2OPO3--
CH2OPO3-C
O
HO
C
H
H
C
OH
H
C
OH
CH2OPO3-O
H
H
C
CH2OPO3--
C
C
OH
O
CH2OH
CH2OPO3--
O
--O3PO
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OPO3--
CH2OH
O
-O
C
C
OPO3--
CH2
O
-O
C
C
O
CH3
BCH 400/600
Spring 2004
Exam 3
March 25
Name_________________________
Multiple Choice (2 points each)
56) A lipid is a compound that is soluble in ___________.
a. nonplolar organic solvents
b. nonpolar aqueous solvents
c. water
d. none of the above
57) Acyl-lipids include all but which of the following?
a. Phospholipids
b. Sterols
c. Fats and oils
d. Sphingolipids
58) Isoprenoids are classes of lipids that are derived from___________.
a. long chain fatty acid precursors
b. 5 carbon isoprene precursors
c. glycerol backbones
d. a and c
e. none of the above
59) Which of the following are common components of phospholipids?
a. phosphate
b. fatty acids
c. glycerol
d. a and b
e. all of the above
60) Membrane proteins and phospholipids can freely diffuse without the input of energy in
__________ dimension(s) within a lipid bilayer.
a. one
b. two
c. three
d. none (they are static in membranes)
61) Long chain saturated fatty acids (i.e. greater than 18 carbons) are _________ at room
temperature.
a. Liquid
b. Solid
c. Gaseous
d. All of the above
62) Which of the following types of membrane transporters do not exhibit saturation
kinetics?
a. Pores/channels
b. passive facilitative transporters
c. active transporters
d. b and c
e. a and b
63) When caffeine inhibits the breakdown of cAMP, a second messenger involved in
epinephrine signaling pathway, the cellular response to epinephrine _____________.
a. ceases quicker
b. is prolonged
c. does not occur
d. none of the above
64) Anabolic processes results in the _________.
a. breakdown of complex molecules to produce simple molecules and the generation
of energy
b. synthesis of complex molecules from simple molecules through the consumption
of metabolic energy
c. none of the above
65) When we say that a biosynthetic pathway is under steady state conditions, we mean that
the rate of the synthesis of pathway intermediates is __________ to the rate of their
utilization
a. higher
b. lower
c. equal
d. variable
66) The in vivo ΔG of a reaction can differ from its corresponding standard ΔG (ΔGo’)
because ___________________________.
a. ΔGo’ alone assumes that reactant and products are at equilibrium concentrations
b. when ΔG is calculated one must factor in the mass action ratio
c. the actual reactant and product concentrations differ in vivo from those measured
at equilibrium
d. all of the above
67) When ΔG is equal to ΔGo’ the reaction is _____________________________.
a. Reversible
b. Irreversible
c. Not catalytically possible
d. None of the above
68) TCA can be described as ____________________________________.
a. an anabolic process.
b. a catabolic process.
c. an amphibolic process
d. None of the above.
69) In a spiral organized metabolic pathway_________________________.
a. the same set of enzymes are used repeatedly
b. the pathway intermediates are recycled.
c. the product of one reaction serves as the substrate for the subsequent reaction.
d. the regulation always occurs at the last step in the pathway.
e. None of the above.
70) The Pasteur Effect refers to the observation that when an organism shifts its metabolism
from aerobic to anaerobic conditions, the rate of glycolysis ___________ .
a. remains the same
b. decreases
c. increases
d. none of the above
71) The net number of moles of ATP produced per mole of glucose consumed during
glycolysis alone is ________________.
a. 1
b. 2
c. 4
d. none of the above
72) Which of the following co-factors is not involved in the reaction catalyzed by pyruvate
dehydrogenase?
a. thiamin pyrophosphate
b. biotin
c. pyridoxal phosphate
d. a and b
e. b and c
73) The ____________ refers to the process by which glucose is regenerated in liver from
lactic acid produced in muscle tissue under anaerobic conditions.
a. Pasteur Effect
b. Bohr Effect
c. Cori cycle
d. None of the above.
74) Which of the following metabolic pathways allows bacteria and plants to convert acetylCoA to glucose?
a. glycolysis
b. Krebs cycle
c. Glyoxylate cycle
d. Pentose phosphate pathway
75) Glycogenin is ___________________________.
a. a long polymer of alpha 1-4 linked glucose molecules
b. the enzyme which breaks down glycogen
c. the protein primer for glycogen synthesis
d. a hormone that is produced under condition of low blood sugar
76) NADPH and five carbon sugars are produced by which of the following biochemical
pathways?
a. glycolysis
b. Krebs cycle
c. Glyoxylate cycle
d. Pentose phosphate pathway
77) Fructose 2,6 bisphosphate is an inhibitor of what enzyme?
a. Pyruvate kinase
b. Aldolase
c. Alpha-ketogluturate dehydrogenase
d. Phosphofructokinase-1
e. Fructose 1,6 bisphosphatase
78) Anapleorotic reactions________________________.
a. generate NADPH and five carbon sugars
b. replace intermediates of the Krebs Cycle that were depleted for use as carbon
skeletons for biosynthetic processes.
c. remove intermediates of the Kreb cycle for use as carbon skeletons for
biosynthetic processes.
d. by pass the oxidative decarboxylation reactions of the Krebs cycle so that acetylCoA can be used to form carbohydrates in plants and bacteria.
79) Which enzyme catalyzes an irreversible step in glycolysis?
a. phosphoglucomutase
b. glyceraldehydes-3-phosphate dehydrogenase
c. pyruvate kinase
d. b and c
e. all of the above
80) Which of the following hormones induces glycogen synthesis when blood glucose levels
are high?
a. glucagon
b. insulin
c. epinephrine
d. a and b
e. a and c
81) (10 points) Draw the structure of phosphatidylethanolamine with an oleic acid attached to
carbon 1 of the glycerol backbone and a linoleic acid attached to carbon 2 of the glycerol
backbone. Make sure to correctly locate all double bonds in each fatty acid structure.
28) (20 points) The next page contains the structures of all of the intermediates of glycolysis.
You need to do the following:
G. (5 points) Draw a unidirectional arrow (Æ) between the substrate and the product
of all irreversible reactions and draw a bidirectional arrow (ÅÆ) between the
substrate and the product of all reversible reactions.
H. (5 points) Write the name of all intermediates of glycolysis from glucose to
pyruvate
I. (5 points) Label the correct reaction with the name of corresponding enzyme for
each enzymatic step of glycolysis.
J. (2 points) For each step that consumes ATP, designate it as follows:
ATP
ADP
Reactant
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
E. (2 points) For each step that generates ATP, designate it as follows:
ADP
ATP
Reactant
Product
Note: the arrow may be unidirectional or bi-directional for these reactions. You are
required to know which is correct.
F. (1 point) For each step that uses NAD/NADH as a cofactor, designate it as follows
NAD+
Reactant
NADH
Product
CHO
H
C
OH
HO
C
H
H
C
H
C
CHO
H
C
OH
HO
C
H
OH
H
C
OH
H
C
CH2OH
CH2OH
C
O
HO
C
H
OH
H
C
OH
OH
H
C
OH
CH2OPO3--
CH2OPO3--
CH2OPO3-C
O
HO
C
H
H
C
OH
H
C
OH
CH2OPO3-O
H
CH2OPO3--
C
H
C
C
OH
O
CH2OH
CH2OPO3--
O
--O3PO
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OPO3--
CH2OH
O
-O
C
C
OPO3--
CH2
O
-O
C
C
O
CH3
Questions 29 - 33. Matching based on the figure below (2 points each)
D
C
E
B
F
29) ____________ Transducer
30) ____________ second messenger
31) ____________ effector enzyme
32) ____________ cytosolic effector enzyme
33) ____________ first messenger
34) (2 points) Label the reaction in the figure below with the correct enzyme name that catalyzes
a substrate level phosphorylation reaction.
35) (4 points) Label the two reactions in the figure below with the correct enzyme names that
catalyzes a oxidative decarboxylation reactions.
36) (2 points) List the names of the two regulatory enzymes of the Krebs cycle.
37) (2 points) Label the reaction in the figure below with the correct enzyme name that donates
electrons directly to the mitochondrial electron transport chain.
BCH400/600
Exam 3
March 14, 2005
Name___________________
Multiple-choice questions (2 points per question)(enter the correct letter for each answer on your
scantron answer sheet)
1) Which of the following is not an isoprenoid?
(a) steroids
(b) phosphatidylcholine
(c) carotenoids
(d) triacyglycerol
(e) b and d
2) Linolenic acid is designated as _____.
(a) 16:0
(b) 16:1
(c) 18:1
(d) 18:2
(e) 18:3
3) Oleic acid is designated as 18:1 Δ9, if carbon number 1 is the carboxyl carbon, where is the double
bond situated?
(a) Between carbons 9 and 10
(b) Between carbons 8 and 10
(c) Between carbons 10 and 11
(d) Between carbons 9 and 10
(e) none of the above.
4) The temperature at which a membrane undergoes transition from a liquid crystalline state to a gel
state depends on _______.
(a) the length of the fatty acids attached to the phospholipids.
(b) the number of double bonds in the fatty acids attached to the phospholipids.
(c) the amount of cholesterol present.
(d) All of the above.
(e) None of the above.
5) Based on the carbon chain length and the degree of unsaturation, which of the following fatty acids
will have the lowest melting temperature?
(a) Palmitic acid
(b) Stearic acid
(c) Oleic acid
(d) Linoleic acid
(e) Linolenic acid
6) Flippases _______________
(a) are proteins that allow lipid molecules to transverse lipid bilayers
(b) are proteins that allow lipid molecules diffuse laterally through a lipid bilayer
(c) is the name of a dolphin in a 1960’s TV series.
(d) are offensive hand gestures.
7) Which of the following is consistent with the steady state model of metabolism?
(a) The concentrations of all pathway intermediates are at equilibrium.
(b) The concentrations of pathway intermediates remain constant because the rate of its
formation is equal to the rate of their utilization.
(c) The concentrations of pathway intermediates decreases because the rate of their formation is
less than the rate of their utilization.
(d) The concentrations of pathway intermediates increase because the rate of their formation is
higher than the rate of their utilization.
(e) None of the above.
8) Which of the following types of membrane transporters show saturable kinetics?
(a) passive (facilitative) transporters
(b) active transporters
(c) pores/channels
(d) a and b
(e) a and c
9) The TCA (Krebs) Cycle is organized as a _________ pathway?
(a) linear
(b) spiral
(c) closed loop
(d) all of the above
(e) none of the above
10) Which of the following metabolic processes is amphibolic?
(a) glycolysis
(b) the TCA cycle
(c) gluconeogenesis
(d) glycogen synthesis
(e) All of the above
11) From what you know about glycolysis, 1,3 bisphosphoglycerate must have __________ phosphoryl
group transfer potential than ATP.
(a) the same
(b) a lower
(c) a higher
(d) b and c
(e) None of the above
12) Under anaerobic conditions, lactic acid and alcoholic fermentation are required to re-oxidize NADH
to NAD+ for use by what enzyme in glycolysis?
(a) hexose kinase
(b) pyruvate kinase
(c) glyceraldehyde-3-phosphate dehydrogenase
(d) phosphoglycerate kinase
(e) enolase
13) The Pasteur Effect describes how under anaerobic conditions the rate of glycolysis is __________
the rate measured under aerobic conditions.
(a) lower than
(b) higher than
(c) the same as
(d) none of the above
14) What is required for glycogen biosynthesis?
(a) glycogenin
(b) UDP-glucose
(c) glycogen synthase
(d) b and c
(e) all of the above
15) Which of the following hormones promotes the breakdown of glycogen?
(a) epinephrine
(b) glucagon
(c) insulin
(d) a and b
(e) all of the above
16) Important products produced by the pentose phosphate pathway include
_______________________.
(a) Acetyl-CoA
(b) NADPH
(c) NADH
(d) glycogen
(e) none of the above
17) How many ATP/GTPs (don’t worry about those from NADH) are consumed during gluconeogenesis
in the formation of one molecule of glucose from 2 molecules of pyruvate?
(a) 2
(b) 4
(c) 6
(d) 8
(e) none
18) How many protons need to transverse the inner mitochondrial membrane to produce one molecule of
ATP in the mitochondrial matrix and deliver it to the cytosol?
(a) 1
(b) 2
(c) 3
(d) 4
19) Uncouplers ______________.
(a) cause the F0F1 ATPase complex to disassociate
(b) dissipate the proton gradient across the inner mitochondrial membrane
(c) inhibit electron transport from complex I.
(d) are hired by the rail road to move box cars around
(e) none of the above
20) The Cori Cycle_____________________.
(a) prevents the accumulation of lactic acid in anerobic muscle tissues
(b)
(c)
(d)
(e)
delivers glucose from the liver to the muscle tissues
delivers lactic acid from the muscle tissues to the liver
requires gluconeogenesis to occur in the liver
all of the above
21) Which of the following protein complexes of the mitochondrial electron transport chain is directly
involved in the consumption of oxygen?
(a) Complex I
(b) Complex II
(c) Complex III
(d) Complex IV
(e) F0F1 ATPase
22) Which of the following steps of glycolysis catalyze substrate level phophorylations?
(a) phosphoglycerate kinase
(b) pyruvate kinase
(c) phosphofructokinase-1
(d) a and b
(e) a and c
23) How many electrons does NADH donate to Complex I of the electron transport chain?
(a) 1
(b) 2
(c) 3
(d) 4
(e) None
24) In relation to the TCA cycle, what are anaplerotic reactions?
(a) They catalyze oxidative decarboxylations.
(b) They catalyze substrate level phosphorylation.
(c) They donate electrons to ubiquinone in the electron transport chain.
(d) They replenish TCA cycle intermediates that have been siphoned off for use in biosynthetic
pathways.
(e) None of the above.
25) Which sub-cellular compartments are involved the generation of ATP from the complete oxidation
of glucose to CO2?
(a) Mitochondrial matrix
(b) Mitochondrial inner membrane space
(c) Mitochondrial inner membrane
(d) Cytosol
(e) All of the above
Matching Questions (2 points each) Match the letters (A thru E) in the figure below with the
corresponding term in questions 26 thru 30. Mark the correct answer on the Scantron sheet
B
G
G
G
G
A
G
3 4 56 7G1 2
1 7766554
3
2
2 31 56 4 2
4 71
α
s β
GDP
C
α
α
s β
GTP
GTP
s
A
ATP
β
C
C
D
cAMP
PPi
PFK-2/
P
PKA
G-6-
P
PKA
E
Phosph
Glycog
E
cAMP
P
PKA
PKA
cAMP
P
26) Transducer
_______
27) Second Messenger
_______
28) Hormone Receptor
_______
29) Effector enzyme
_______
30) Cytoplasmic effector enzyme
_______
Matching Questions (2 points each) Match the letters (each letter can be used more than once) with the
corresponding term in questions 31 thru 35. k the correct answer on the Scantron sheet
31) pyruvate dehydrogenase_______
(a) catalyzes substrate level phosphorylation
32) isocitrate dehydrogenase_______
(b) enzyme specific to the glyoxylate cycle
33) isocitrate lyase_______
(c) donates electrons directly to ubiquinone pool
34) succinate dehydrogenase_______
(d) catalyzes an oxidative decarboxylation reaction
35) succinyl-CoA synthetase_______
(e) catalyzes an anaplerotic reaction
36) (10 points) The next page contains the structures of all of the intermediates of glycolysis.
You need to do the following:
K. (3 points) Draw a unidirectional arrow (Æ) between the substrate and the product
of all irreversible reactions.
L. (6 points) Write the name of all substrates, products, co-factors, co-substrates for
the irreversible reactions of glycolysis
M. (3 points) Label the correct reaction with the name of corresponding enzyme for
each irreversible enzymatic step of glycolysis.
N. (3 points) Beside the enzyme name of each irreversible reaction of glycolysis, list
all corresponding allosteric inhibitors.
CHO
H
C
OH
HO
C
H
H
C
H
C
CHO
H
C
OH
HO
C
H
OH
H
C
OH
H
C
CH2OH
CH2OH
C
O
HO
C
H
OH
H
C
OH
OH
H
C
OH
CH2OPO3--
CH2OPO3--
CH2OPO3-C
O
HO
C
H
H
C
OH
H
C
OH
CH2OPO3-O
H
CH2OPO3--
C
H
C
C
OH
O
CH2OH
CH2OPO3--
O
--O3PO
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OPO3--
CH2OH
O
-O
C
C
OPO3--
CH2
O
-O
C
C
O
CH3
Short answer (5 points each) You are required to answer 4 questions. You may answer a 5th
question for extra credit. Please be complete, but BRIEF!!!!! I will not grade more than 5
answers. So circle the question number to make sure it is clear which questions you want
me to grade.
37) Explain why more ATP is produced when electrons enter the electron transport chain from Complex I
that when electrons enter the electron transport chain from Complex II?
38) Why is the electron transport chain intentionally uncoupled from ATP production in hibernating
animals?
39) During glycolysis, glucose-6-phosphate is converted to fructose-6-phosphate by the enzyme
phosphoglucose isomerase. Why is this reaction so important for the formation of two 3 carbon compounds?
40) What is the major force driving used to transport compounds across a membrane using a pore or passive
transporter? List at least two properties that distinguish pores from passive transporters.
41) Why can plants use acetyl-CoA as a precursor for carbohydrate biosynthesis while animals and humans
can’t?
42) Explain how the Kcat of the GTPase activity of a G-protein transducer effects the duration of the
activation of a signal transduction pathway?
43) Caffeine is a stimulant. It has been shown to inhibit the enzyme cAMP phosphodiesterase, an enzyme
that breaks down cAMP. What effect would caffeine have on the signal transduction pathway drawn on
page 5 of this exam?
44) Describe how the Cori Cycle connects glycolysis and lactic acid fermentation in anaerobic muscle
tissues to gluconeogenesis in the liver.
Dr. Shintani’s Midterm Evaluation
Please detach this page from you test and fill out this questionnaire. But do not put your name on this sheet.
You can either turn it into my Grad-student, Imad Ajjawi who is proctoring the exam or give it to the
secretary in Fleischman Ag Room 311. Your constructive criticism is appreciated and will help me improve
the course. I have enjoyed having all of you in my class this semester and want to make this course a
worthwhile experience for you.
Are you satisfied with the level at which the material is being taught? If not why?
Do you feel that the test have been fair? If not why?
Do you like the lecture style? If not, do you have suggestions on how my lectures could be improved?
Do you like the test format? If not, do you have suggestions on how it could be improved?
BCH 400/600
March 28, 2006
Exam 3
Name
For questions 1 through 30 mark the correct answer on the provided scantron answer sheet and
on this exam.
Multiple Choice Questions (2 points per question)
1) Which of the following polysaccharides are formed from monosaccharides joined by
alpha-1,4 glycosidic linkages?
a. Cellulose
b. chitin
c. starch
d. a and b
e. all of the above
2) Which of the following polysaccharides form linear, unbranched polymers?
a. glycogen
b. Chitin
c. Starch
d. a and b
e. all of the above
3) Glycosidic linkages are formed through a _____________ reaction.
a. hydrolysis
b. condensation
c. isomerization
d. all of the above
e. none of the above
4) Which of the following are disaccharides?
a. sucrose
b. lactose
c. maltose
d. cellobiose
e. all of the above
5) What types of forces hold different strands of cellulose together in cable like fibers?
a. Ionic bonds
b. Covalent bonds
c. hydrophobic interactions
d. hydrogen bonds
e. van der Waals forces
6) Of the listed signal transduction pathway components below, which is the transducer?
a. epinephrine receptor
b. epinephrine
c. cAMP
d. G-protein
e. Adenyl cyclase
7) N-linked saccharides are attached to proteins at what specific amino acid residue?
a. threonine
b. serine
c. tyrosine
d. asparagine
e. alanine
8) Which type of glycoproteins form extended “bristle brush” like conformations?
a. N-linked
b. O-linked
c. Chain-linked
d. Sausage linked
e. Cuff linked
9) What is the major difference between the cell wall of a gram positive bacteria and the cell
wall of a gram negative bacteria?
a. gram negative bacteria lack peptidoglycan
b. gram negative bacteria lack a pentaglycine linker between strands
c. gram positive bacteria lack cell walls
d. none of the above
10) Which of the following fatty acids is not saturated?
a. palmitate
b. oleate
c. stearate
d. laurate
e. all of the above
11) An 18 carbon fatty acid with a single double bond between the 9th and 10th carbon is
called _______.
a. oleate
b. palmitate
c. stearate
d. linoleate
e. none of the above
12) Which of the following fatty acids has the highest melting temperature?
a. 18:0
b. 18:1
c. 18:2
d. 18:3
e. 20:0
13) Steroids belong to which major lipid class?
a. acyl-lipids
b. phospholipids
c. sphingolipids
d. isoprenoids
e. a, b and c
14) ___________ do not show saturable kinetics.
a. passive transporters
b. active transporters
c. pores/channels
d. a and c
e. all of the above
15) Membrane bound proteins (intrinsic and peripheral) can freely diffuse in ________
dimensions within a membrane bilayer.
a. 1
b. 2
c. 3
d. They don’t diffuse
16) Soluble proteins can be anchored to membranes through covalent linkages with
_________________.
a. fatty acids
b. isoprenoids
c. phosphytidylcholine
d. a and b
e. All of the above
17) Diffusion is process by which solutes _________________________.
a. move from a site with low solute concentration to a site with high solute
concentration
b. move from a site with high solute concentration to a site with low solute
concentration
c. move randomly and independently of solute concentration
d. none of the above
18) The enzyme pyruvate dehydrogenase is required for the conversion of pyruvate from
glycolysis to acetyl-CoA for the TCA cycle. Which of the following cofactors are used in
the reaction catalyzed by pyruvate dehydrogenase?
a. Thiamin pyrophosphate
b. Lipoamide
c. FAD+
d. Coenzyme A
e. All of the above
19) After glycolysis has converted one molecule of glucose to two molecules of pyruvate,
what is the net yield of ATP from this process alone?
a. 1
b. 2
c. 3
d. 4
e. 6
20) Under anaerobic conditions, alcoholic or lactic acid fermentations are required
to____________________.
a. get rid of excess pyruvate
b. generate ATP
c. to regenerate NADH for use by glyceraldehyde dehydrogenase
d. to regenerate NAD+ for use by glyceraldehyde dehydrogenase
e. all of the above
21) Which of the following reactions does not generate ATP through a substrate level
phosphorylation?
a. Phosphoglycerate kinase
b. Pyruvate kinase
c. Pyruvate kinase
d. Succinyl-CoA synthetase
e. hexokinase
22) The enzymes in the TCA cycle are organized as _________________.
a. a closed loop pathway
b. a linear pathway
c. a spiral pathway
d. a and c
e. all of the above
23) Which of the following reactions generates the lowest amount of energy?
a. ATP ÆADP + Pi
b. ATP Æ AMP + Pi
c. PPi ÆPi + Pi
d. AMP Æ adenosine + Pi
24) The anaplerotic reactions of the TCA cycle ______________.
a. resupply the TCA cycle with intermediates
b. occur during anaerobic conditions
c. allow the TCA cycle to function as an anabolic pathway
d. a and c
e. None of the above
25) Where in the mitochondria are the enzymes of the TCA cycle localized?
a. mitochondrial matrix
b. inner membrane of the mitochondria
c. the inner membrane space of the mitochondria
d. a and b
e. a and c
26 (10 points) Match each enzyme with the letters corresponding to all correct characteristics
listed to the right. You can use each letter more than once and there will be multiple answers for
some enzymes. List all correct answers on this sheet. DON”T PUT YOUR ANSWERS ON THE
SCANTRON!!
___________ pyruvate dehydrogenase
a. oxidative decarboxylation
___________ isocitrate dehydrogenase
b. generates GTP
____________ succinate dehydrogenase
c. donates electron directly to the
mitochondrial electron transport chain
____________ succinyl-CoA synthetase
d. regulatory enzyme for the TCA cycle
____________ malate dehydrogenase
e. NADH is generated during this step
f. enzyme to connects glycolysis to the TCA
cycle
27) (20 points) The next page contains the structures of all of the intermediates of glycolysis
from glucose to pyruvate. You need to do the following:
O. Draw a unidirectional arrow (Æ) between the substrate and the product of all
irreversible reactions.
P. Draw a bidirectional arrow (ÅÆ) between the substrate and the product of all
reversible reactions.
Q. For each step that consumes ATP, designate it as follows:
ATP
ADP
Reactant
Product
R. For each step that generates ATP, designate it as follows:
ADP
Reactant
ATP
Product
S. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
reaction substrate and the name of the reaction product next to the correct
structure.
T. For the 3 regulated enzymatic reactions of glycolysis, write the name of the
enzyme
CHO
H
C
OH
HO
C
H
H
C
OH
H
C
OH
CHO
CH2OH
H
C
C
HO
C
H
HO
C
H
H
C
OH
H
C
OH
H
C
OH
H
C
OH
CH2OH
OH
CH2OPO3--
O
CH2OPO3--
CH2OPO3-C
O
HO
C
H
H
C
OH
H
C
OH
CH2OPO3-O
H
CH2OPO3--
C
H
C
C
OH
O
CH2OH
CH2OPO3--
O
--O3PO
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OH
CH2OPO3--
O
-O
C
H
C
OPO3--
CH2OH
O
-O
C
C
OPO3--
CH2
O
-O
C
C
O
CH3
28) (5 points) Fill in the table below with the correct number of high energy compounds
generated during each process starting with one molecule of glucose and ending with 6
molecules of CO2. Assuming each NADH generates 2.5 ATPs, in column 3 list the total number
of ATPs generated from substrate level phosphorylation and from NADH.
Column 1
ATPs from substrate
level phosphorylations
Column 2
Number of NADHs
Generated
Column 3
Total ATPs
generated
Glycolysis
Pyruvate dehydrogenase
TCA Cycle
Total
Questions 29 through 34. Short Answer (5 points each) You are required to answer 3 questions.
You may answer a 4th question for extra credit. I will not grade more than 4 questions so make
sure to circle the questions that you want me to grade.
29) What is the Cori cycle and how does it relate to glycolysis?
30) How does the glyoxylate cycle prevent the complete oxidation of acetyl-CoA and
allow acetyl-CoA to serve as a precursor for carbohydrate biosynthesis?
31) Why is the TCA cycle considered an amphibolic pathway?
32) Caffeine acts to prevent the deactivation of the epinephrine signaling pathway.
How does caffeine accomplish this fete?
33) Close examination of a biological membrane shows that the composition of
phospholipids on one side of the bilayer is significantly different from the
composition of phospholipids on the other side of the bilayer. Since it is
thermodynamically unfavorable for phospholipids to transverse the membrane,
how do the opposite sides of biological membranes become asymmetric in
regards to phospholipid composition?