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(Aviram’s Questions)
1) The precursor of the fatty acid C-18:2, n-9,12 is:
a.
b.
c.
d.
e.
Oleic acid (ω-9)
Palmitoleic acid (ω-7).
Linoleic acid (ω-6)
Linolenic acid (ω-3)
Palmitic acid
2) How many ATP molecules are formed from a full oxidation of Palmitoleic acid
(C-16:1, odd carbon):
a.
b.
c.
d.
e.
122
118
104.5
108
110
3) Analysis of serum obtained from a patient with carnitine acyltransferase deficiency
after a long fast will show:
a.
b.
c.
d.
e.
Low glucose and high fatty acids levels.
High glucose and high fatty acids levels.
Low glucose and low fatty acids levels.
High glucose and low fatty acids levels.
Low glucose and no effect of free fatty acids levels.
4) How many ATP molecules can be formed from the full oxidation of the fatty acid C18:1 (odd carbon)?
a.
b.
c.
d.
e.
117
118.5
122
120
106
5) β-oxidation of the fatty acid C-18:2, n-9,12 requires, in addition to the 4 β-oxidation
enzymes, also:
a.
b.
c.
d.
e.
Isomerase
Translocase
Mutase
Isomerase and 2,4-Dienoyl Reductase
Transketolase
6) Lauric acid (C-12:0) biosynthesis from acetyl CoA requires:
a.
b.
c.
d.
e.
5 ATP, 10 NADPH
6 ATP, 12 NADPH
6 ATP, 6 NADPH
12 ATP, 12 NADPH
6 ATP, 10 NADPH
7) How many ATP and NADPH molecules are needed for the synthesis of palmitic acid
(C-16:0) from Acetyl CoA?
a.
b.
c.
d.
e.
7 ATP, 14 NADPH
7 ATP, 7 NADPH
14 ATP, 14 NADPH
8 ATP, 8 NADPH
8 ATP, 14 NADPH
8) During the initial steps of cholesterol biosynthesis, NADPH is required for:
a.
b.
c.
d.
e.
Condensation of 2 Acetyl CoA molecules.
HMGCoA synthase (Aceto acetyl CoA + Acetyl CoA).
HMGCoA reductase (HMGCoA reduction to mevalonate).
Mevalonate reduction.
Acetoacetate reduction
9) The rate limiting enzyme in cholesterol biosynthesis is:
a.
b.
c.
d.
e.
HMGCoA Lyase in the mitochondria
HMGCoA Reductase in the cytosol
HMGCoA Reductase in the mitochondria
HMGCoA Lyase in the cytosol
Acetyl CoA Carboxylase in the cytosol.
10) What are the cholesterol levels of serum LDL and VLDL in a subject with the
following lipid profile: Cholesterol – 220%, Triglycerides – 100mg%, HDL
cholesterol – 50 mg%?
a.
b.
c.
d.
LDL 150 mg%, VLDL -20mg%
LDL -130mg%, VLDL -15mg%
LDL -150mg%, VLDL -25mg%
LDL 130mg%, VLDL -15mg%
11) LDL receptor, which is not located at the coated pits:
a.
b.
c.
d.
e.
Does not bind LDL.
Does not internalize LDL.
Does not bind VLDL.
Does not bind oxidized LDL.
It is always in the coated pits.
12) During the formation of LDL from VLDL in the blood there is no involvement of:
a.
b.
c.
d.
e.
Arterial lipoprotein lipase
Hepatic lipoprotein lipase
Apolipoprotein lipase
VLDL triglycerides hydrolysis
Fatty acids formation
13) The appropriate therapy for a patient with serum total cholesterol levels of 210 mg%,
HDL cholesterol levels of 90 mg%, and serum total triglycerides levels of 290 mg%
is:
a.
b.
c.
d.
e.
Simvastatin to decrease his high LDL.
Cholestyramin to decrease his high LDL
Bazafibrate to decrease his high VLDL.
Vitamin E to increase his low HDL.
No therapy is needed as his serum lipids levels are normal.
14) Increased activity of serum lecithine cholesterol acyl transferase (LCAT) results in:
a.
b.
c.
d.
e.
An increase in both HDL cholesterol ester and phospholipids.
An increase in HDL cholesterol ester and a decrease in HDL phospholipids.
A decrease in both HDL cholesterol ester and phospholipids.
No effect on HDL lipids.
An increase in HDL apo A-I and a decrease in HDL apo A-II
(Miriam David’s Questions)
15) In mitochondria, tricarboxylic acid cycle reactions generally proceed more:
(1) slowly as the ADP concentration rises.
(2) rapidly as the ADP concentration rises.
(3) rapidly as the NADH concentration rises.
(4) slowly as the NADH concentration rises.
(5) slowly as the oxaloacetate concentration increases.
a.
b.
c.
d.
e.
1 and 3
2 and 4
3 and 5
1 and 4
2 and 3
16) The uncoupling of oxidative phosphorylation in the human might be of physiological
importance because it:
a.
b.
c.
d.
e.
allows storage of nutrients.
produces water.
increases carbon dioxide level in the blood.
raises the oxygen level in the blood.
produces heat.
17) Which of the following is the most accurate description of phosphofructokinase-1?
a. This enzyme uses fructose-6-phosphate as a substrate and converts it to
fructose-2,6-biphosphate
b. This enzyme is inhibited by ATP, citrate and fructose-2,6-biphosphate
c. This enzyme catalyzes a fully reversible reaction under physiological conditions.
d. No statement above is accurate.
18) What is the net yield of NADH when glucose 6-phosphate is converted to lactate by
anaerobic glycosis?
a.
b.
c.
d.
e.
0
1
2
3
4
19) The chemiosmotic hypothesis suggests that the potential energy of the electrons
moving down the mitochondrial electron transport chain from a negative to a positive
oxidation potential is initially conserved in the form of a:
a.
b.
c.
d.
high energy phosphate bond.
protonated form of coenzyme Q.
proton gradient across the membrane.
reduced iron ion (Fe2+) in the cytochrome.
20) Gluconeogenesis from lactate does not require activity of:
a.
b.
c.
d.
aldolase.
phosphofructokinase.
glyceraldehydes 3-phosphate dehydrogenase.
triose phosphate isomerase.
21) In order for an electron transfer reaction to be energetically spontaneous, which of the
following must be true?
a.
b.
c.
d.
The change in reduction potential, ΔE0, must be negative.
The change in reduction potential, ΔE0, must be positive.
The two groups involved in the electron transfer must be in direct contact.
The change in reduction potential, ΔE0, must be zero.
22) The glycogen molecule has two types of linkages between the glucose molecules of
which it is composed. Of these, the ______________ linkage is broken by the
glycogen phosphorylase enzyme and the _______________ linkage is not.
a.
b.
c.
d.
α -1,6
β -1,4
α -1,4
α -1,4
α -1,4
α -1,6
α -1,6
β -1,4
23) Which of the following is not true of the reaction catalyzed by the pyruvate
dehydrogenase complex?
a.
b.
c.
d.
Biotin participates.
NAD+ participates.
Occurs in the mitochondrial matrix.
A cofactor containing –SH group participates.
24) Galactosemia is a genetic error of metabolism associated with:
a.
b.
c.
d.
inability to digest lactose.
excessive ingestion of galactose.
deficiency of UDP-glucose.
deficiency of galactose 1-phosphate uridylyltransferase.
25) Which of the following compounds cannot serve as the starting material for the
synthesis of glucose via gluconeogenesis?
a.
b.
c.
d.
acetate.
glycerol.
lactate.
oxaloacetate.
26) The purpose of anaplerotic reactions is
a. to divert materials out of the citric acid cycle for use in biosynthesis.
b. to produce pyruvate to initiate the cycle when glucose degradation is not
occurring.
c. to replenish the citric acid cycle if it becomes depleted of intermediates by
biosynthetic demands.
d. to replenish the pool of the amino acids with glutamate and aspartate.