BIOENERGETICS - CHOLESTEROL Flashcards
(358 cards)
1
Q
G protein that promotes activation and
intracellular signaling
A. Ion channel
B. cAMP second messenger
C. Phospholipase C second messenger
D. AOTA
A
D. AOTA
2
Q
Least describes eicosanoids
A. Derived from C18 eicosanoids
B. Ibuprofen inhibits cyclooxygenase
C. Prostacyclin inhibits platelet aggregation
D. Group 3 eicosanoids include PGD3, TXA3 and
LTB5
A
A. Derived from C18 eicosanoids
Arachidonate and some other C20
polyunsaturated fatty acids give rise to
eicosanoids, physiologically and
pharmacologically active compounds known as
prostaglandins (PG), thromboxanes (TX),
leukotrienes (LT), and lipoxins (LX) (see Chapter
21). Physiologically, they are considered to act as
local hormones functioning through G-protein-
linked receptors to elicit their biochemical
effects.
3
Q
Transfer of fatty acids from cytoplasm to the
mitochondrial matrix requires:
A. ATP, carnitine, co-enzyme A
B. ATP, co-enzyme A, hexokinase
C. ATP, carnitine, pyruvate dehydrogenase
D. ATP, co-enzyme A, pyruvate dehydrogenase
A
A. ATP, carnitine, co-enzyme A
In the presence of ATP and coenzyme A, the
enzyme acyl-CoA synthetase (thiokinase)
catalyzes the conversion of a fatty acid (or FFA)
to an “active fatty acid” or acyl-CoA, using one
high-energy phosphate and forming
AMP and PPi (Figure 22–1).
Long-chainacyl-CoA (or FFA) cannot penetrate
the inner membrane of mitochondria. In the
presence of carnitine, however, carnitine
palmitoyl transferase-I, located in the outer
mitochondrial membrane, transfers long-chain
acyl group from CoA to carnitine, forming
acylcarnitine and releasing CoA. Acylcarnitine is
able to penetrate the inner membrane and gain
access to the β-oxidation system of enzymes via
the inner membrane exchange transporter
carnitine-acylcarnitine translocase.
4
Q
Correct order of fxn of enzymes in beta
oxidation
1. Thiolase
2. Enoyl CoA hydratase
3. Beta hydroxyacyl CoA dehydrogenase
4. Acyl CoA dehydrogenase
A. 1,2,3,4
B. 4,3,1,2
C. 4,2,3,1
D. 2,4,3,1
A
C. 4,2,3,1
5
Q
Not true of oxidation of 1 mol palmitate in
B oxidation, beginning with free fatty Acid in
cytoplasm.
A. 8 mol of acety CoA formed
B. 2 ATPs required for activating fatty acids
C. Inorganic pyrophosphate (PPi) is produced
D. Carnitine functions as an electron acceptor
A
B. 2 ATPs required for activating fatty acids
In the presence of ATP and coenzyme A, the
enzyme acyl-CoA synthetase (thiokinase)
catalyzes the conversion of a fatty acid (or FFA)
to an “active fatty acid” or acyl-CoA, using one
high-energy phosphate and forming AMP and
PPi.
6
Q
Fatty acids with odd number of carbon
enters the citric acid cycle as acetyl coA and
A. Alpha keto glutarate
B. Succinyl coA
C. Acetyl CoA
D. Citrate
A
B. Succinyl coA
Fatty acids with an odd number of carbon atoms
are oxidized by the pathway of β-oxidation
described above producing acetyl CoA until a
three-carbon (propionyl-CoA) residue remains.
This compound is converted to succinyl-CoA, a
constituent of the citric acid cycle (see Figure 16–
2). Hence, the propionyl residue from an odd-
chain fatty acid is the only part of a fatty acid
that is glucogenic.
7
Q
Every cycle of beta oxidation of FA yield
A. 1 FAD, 1 NADH, 2 CO2 molecules
B. 1 FADH2, 1 NADH, 1 Acetyl coA
C. 1 FADH2, 1 NAD+, 1 Acetly coA
D. 1 FAD, 1 NAD+, 2 CO2 molecules
A
B. 1 FADH2, 1 NADH, 1 Acetyl coA
8
Q
Jamaican vomiting sickness, hypoglycin,
what mechanism?
A
Jamaican vomiting sickness is caused by
eating the unripe fruit of the akee tree, which
contains the toxin hypoglycin. This inactivates
medium- and short-chain acyl-CoA
dehydrogenase, inhibiting β-oxidation and
causing hypoglycemia.
9
Q
In extrahepatic tissues, the activation of
acetoacetate to acetyl-coa
A. Acyl CoA synthase
B. HMG CoA lyase
C. CoA transferase
D. Acyl CoA dehydrogenase
A
C. CoA transferase
In extrahepatic tissues, acetoacetate is activated
to acetoacetyl-CoA by succinyl-CoA-
acetoacetate CoA transferase. CoA is
transferred from succinyl-CoA to form
acetoacetyl-CoA.
10
Q
Function of lipoprotein lipase
A. Intracellular lipid breakdown of lipoprotein
B. Intestinal uptake of dietary fat
C. Hydrolysis of TAG to supply the fatty needs of
the different tissues of the body
D. Lipoprotein breakdown
A
C. Hydrolysis of TAG to supply the fatty needs of
the different tissues of the body
Both phospholipids and apo C-II are required as
cofactors for lipoprotein lipase activity, while
apo A-II and apo C-III act as inhibitors. Hydrolysis
takes place while the lipoproteins are attached
to the enzyme on the endothelium.
Triacylglycerol is hydrolyzed progressively
through a diacylglycerol to a monoacylglycerol
and finally to FFA plus glycerol.
11
Q
Major sphingolipids that lacks in lungs
causing respiratory distress syndrome.
A. Glycospingolipid
B. Inositol Phospholipid
C. Ceramide
D. Dipalmitoyl phosphatidylcholine
A
D. Dipalmitoyl phosphatidylcholine
Deficiency of Lung Surfactant Causes
Respiratory Distress Syndrome
Lung surfactant is composed mainly of lipid with
some proteins and carbohydrate and prevents
the alveoli from collapsing.
The phospholipid dipalmitoyl
phosphatidylcholine decreases surface tension
at the air-liquid interface and thus greatly
reduces the work of breathing, but other
surfactant lipid and protein components are also
important in surfactant function. Deficiency of
lung surfactant in the lungs of many preterm newborns gives rise to infant
respiratory distress syndrome (IRDS).
Administration of either natural or artificial
surfactant is of therapeutic benefit.
12
Q
Which of these are a correct match?
A. Krabbes- ceramide
B. Niemann-pick- B-glucosidase
C. Fabry Disease- A- galactosidase
D. Tay-sachs- sphingomyelinase
A
C. Fabry Disease- A- galactosidase
13
Q
Least correct of ceramide
A
Ceramide (see Chapter 21) is synthesized in the
endoplasmic reticulum from the amino acid
serine as shown in Figure 24–7.
Ceramide is an important signaling molecule
(second messenger) regulating pathways
including programmed cell death (apoptosis),
the cell cycle, and cell differentiation and
senescence.
14
Q
VLDL main lipid component
A. TAG
B. Cholesterol
C. Cholesterol ester
D. Phospholipid
A
A. TAG
15
Q
Apoprotein exclusively found in
chylomicron
A. B48
B. B100
C. AOTA
D. NOTA
A
A. B48
16
Q
Accumulation of acetyl-coA in the
mitochondria of the liver
A. Broken down into FFA
B. Used as an energy source
C. Converted into oxaloacetate
A
C. Converted into oxaloacetate
Glycolysis (see Chapter 17), the pentose
phosphate pathway (see Chapter 20), and fatty
acid synthesis (see Chapter 23) all occur in the
cytosol. In gluconeogenesis (see Chapter 19),
substrates such as lactate and pyruvate, which
are formed in the cytosol, enter the
mitochondrion to yield oxaloacetate as a
precursor for the synthesis of glucose in the
cytosol.
17
Q
Which of the following hormone is not used
in the hydrolysis of lipids?
A. ACTH
B. TSH
C. Glucagon
D. Insulin
A
D. Insulin
The rate of release of FFA from adipose tissue is
affected by many hormones that influence either
the rate of esterification or the rate of lipolysis.
Insulin inhibits the release of FFA from adipose
tissue, which is followed by a fall in circulating
plasma free fatty acids. Insulin also enhances
lipogenesis and the synthesis of acylglycerol and
increases the oxidation of glucose to CO2 via the
pentose phosphate pathway.
18
Q
Action of hormone sensitive triacylglycerol
lipase
A. Synthesis of FFA in adipose tissue
B. Hydrolysis of FFA in adipose tissue
C. Synthesis of FFA in liver
D. Hydrolysis of FFA in liver
A
B. Hydrolysis of FFA in adipose tissue
Triacylglycerol undergoes hydrolysis by a
hormone-sensitive lipase to form FFA and
glycerol. This lipase is distinct from lipoprotein
lipase, which catalyzes lipoprotein triacylglycerol
hydrolysis before its uptake into extrahepatic
tissues.
19
Q
How are primary bile acids converted to
secondary bile acids?
A. Enzyme produced by exocrine pancreas
B. Enzymes present in duodenum
C. Enzymes present in gallbladder
D. Bacterial oxidation in small intestines
A
D. Bacterial oxidation in small intestines
Primary bile acids are further metabolized in the
intestine by the activity of the intestinal bacteria.
Thus, deconjugation and 7α-dehydroxylation
occur, producing the secondary bile acids,
deoxycholic acid, and lithocholic acid.
20
Q
Intracellular cholesterol upregulated by this
transcription factor
A. HMG coA
B. SREBP
C. Sterol proteolytic enzymes
D. HMG coA reductase
A
B. SREBP
Cholesterol and metabolites repress
transcription of the HMG-CoA reductase via
activation of a sterol regulatory element-
binding protein (SREBP) transcription factor.
SREBPs are a family of proteins that regulate
the transcription of a range of genes involved in
the cellular uptake and metabolism of
cholesterol and other lipids
21
Q
Dyslipoproteinemia with increased HDL
concetration
A. Familial hypertriacylglycerolemia
B. Familiar hyperalphalipoproteinemia
C. Tangier disease
D. Abetalipoproteinemia
A
B. Familiar hyperalphalipoproteinemia
22
Q
Synthesis of glucose from lactate, glycerol
A. Glycolysis
B. Lipolysis
C. Gluconeogenesis
D. Glycogenesis
A
C. Gluconeogenesis
Gluconeogenesis is the process of synthesizing
glucose or glycogen from noncarbohydrate
precursors. The major substrates are the
glucogenic amino acids (see Chapter 29), lactate,
glycerol, and propionate.
23
Q
Formed from glucose, used for lactating
mammary gland.
A. Fructose
B. Glucose
C. Galactose
D. Maltose
A
C. Galactose
Galactose is derived from intestinal hydrolysis of
the disaccharide lactose, the sugar found in milk.
It is readily converted in the liver to glucose.
24
Q
Oxidation, amination of amino acid alanine
in the liver produces
A. A molecule of pyruvic acid and a molecule of
ammonia
B. A molecule of pyruvic acid and carbon dioxide
C. A molecule of pyruvic acid and water
D. A molecule of pyruvic acid and lactate
A
A. A molecule of pyruvic acid and a molecule of
ammonia
Most of this is transaminated to alanine, at the
expense of amino acids arising from breakdown
of muscle protein. The alanine, and much of the
keto acids resulting from this transamination are
exported from muscle, and taken up by the liver,
where the alanine is transaminated to yield
pyruvate. The resultant amino acids are largely
exported back to muscle, to provide amino
groups for formation of more alanine, while the
pyruvate provides a substrate for
gluconeogenesis in the liver
25
Pyruvate Dehydrogenase:
A. Located in the Sarcoplasm
B. Catalyzes the conversion of Pyruvate to
Acetyl-CoA
C. Catalyzes the conversion of Pyruvate to
Lactate
D. Catalyzes the conversion of Lactate to
Pyruvate
E. Uses molecular Oxygen to remove a molecule
of Carbon Dioxide from Pyruvate
B. Catalyzes the conversion of Pyruvate to
Acetyl-CoA
Pyruvate, formed in the cytosol, is transported
into the mitochondrion by a proton symporter.
Inside the mitochondrion, it is oxidatively
decarboxylated to acetyl-CoA by a multienzyme
complex that is associated with the inner
mitochondrial membrane. This pyruvate
dehydrogenase complex is analogous to the α-
ketoglutarate dehydrogenase complex of the
citric acid cycle
26
Rate of tubular reabsorption of glucose
A. 10mmol/L
B. 2mmol/L
C. 10mmol/min
D. 2mmol/min
E. 2mmol/sec
D. 2mmol/min
27
The ff substances cause the release of
insulin in the pancreas except:
a. amino acid
b. non-esterified fatty acids
c. ketone bodies
d. secretin
e. none of the above
e. none of the above
Other substances causing release of insulin from
the pancreas include amino acids, nonesterified
fatty acids, ketone bodies, glucagon, secretin,
and the sulfonylurea drugs tolbutamide and
glyburide.
28
Catalyzes the transfer of 3-C
dihydroxyacetone from the ketose
sedoheptulose-7-phosphate.
A. Transketolase
B. Transaldolase
C. Reductase
D. Transaminase
B. Transaldolase
Transaldolase catalyzes the transfer of a three
carbondihydroxyacetone moiety (carbons 1–3)
from the ketose sedoheptulose-7-phosphate
onto the aldose glyceraldehyde- 3-phosphate to
form the ketose fructose 6-phosphate and the
four-carbon aldose erythrose 4-phosphate.
29
Enzyme that catalyzes H2O2 in conjunction
with glutathione
A. Glutathione reductase
B. Glutathione dehydrogenase
C. Glutathione peroxidase
D. UDPGIc reductase
E. UDPGIc peroxidase
C. Glutathione peroxidase
Reduced glutathione removes H2O2 in a reaction
catalyzed by glutathione peroxidase, an enzyme
that contains the selenium analog of cysteine
(selenocysteine) at the active site
30
Hereditary disorder caused by the lack of
xylulose reductase.
A. A. G6PD deficiency
B. Fructosuria
C. Essential Pentosuria
D. Fructosuria
C. Essential Pentosuria
In the rare benign hereditary condition essential
pentosuria, considerable quantities of xylulose
appear in the urine, because of a lack of xylulose
reductase, the enzyme necessary to reduce
xylulose to xylitol
31
Glucose in lactating mammary gland that is
needed for the synthesis of other tissues for
glycolipid, proteoglycan, etc
A. Fructose
B. Galactose
C. Sucrose
B. Galactose
32
Major sugar found in seminal fluid.
A. Glucose
B. Fructose
C. Galactose
D. Lactose
B. Fructose
Fructose is found in seminal plasma and in the
fetal circulation of ungulates and whales. Aldose
reductase is found in the placenta of the ewe and
is responsible for the secretion of sorbitol into
the fetal blood. The presence of sorbitol
dehydrogenase in the liver, including the fetal
liver, is responsible for the conversion of sorbitol
into fructose. This pathway is also responsible
for the occurrence of fructose in seminal fluid
33
Organ responsible for the majority of serine
uptake in the peripheral tissues, liver and
muscles
A. Heart
B. Brain
C. Kidneys
D. Liver
C. Kidneys
The kidney provides a major source of serine for
uptake by peripheral tissues, including liver and muscle. Branched-chain amino acids, particularly
valine, are released by muscle and taken up
predominantly by the brain
34
Major end product of nitrogen catabolism in
humans
A. Ammonia
B. Creatinine
C. Urea
C. Urea
Urea is the Major End Product of Nitrogen
Catabolism in Humans
Synthesis of 1 mol of urea requires 3 mol of ATP,
1 mol each of ammonium ion and of aspartate,
and employs five enzymes (Figure 28–16). Of the
six participating amino acids, N-acetylglutamate
functions solely as an enzyme activator. The
others serve as carriers of the atoms that
ultimately become urea.
35
substance involved in the stimulation of
protein kinase activity
a. ATP
b. cAMP
c. Calcium
d. Magnesium
b. cAMP
in prokaryotic cells, cAMP binds to a
specific protein called cAMP activator protein
(CAP) that binds directly to DNA and influences
gene expression. By contrast, in eukaryotic cells,
cAMP binds to a protein kinase called protein
kinase A (PKA), a heterotetrameric molecule
consisting of two regulatory subunits (R) that inhibit the activity of the two catalytic subunits
(C) when bound as a tetrameric complex.
36
ATP produced in oxidation of 1 mol of C16
fatty acid. ANS: net = 106
a. 8
b. 28
c. 80
d. 108
d. 108
The breakdown of 1 mol of palmitate,
therefore, yields a gross total of 108 mol of ATP.
However, two high-energy phosphates are used
in the initial activation step (Figure 22–3), thus
there is a net gain of 106 mol of ATP per mole of
palmitate used.
37
least describes KETOGENESIS
a. Fatty acids must be activated before
being catabolized
b. B-oxidation cycle generates FADH2 and
NADH
c. Long chain fatty acids penetrate inner
mitochondrial membrane
d. Conversion of fatty acid to Acyl-CoA
requires 1 high energy Phosphate
c. Long chain fatty acids penetrate inner
mitochondrial membrane
Long-chain acyl-CoA (or FFA) cannot
penetrate the inner membrane of mitochondria.
In the presence of carnitine, however, carnitine
palmitoyltransferase-I, located in the outer
mitochondrial membrane, transfers the long-
chain acyl group from CoA to carnitine, forming
acylcarnitine and releasing CoA.
38
Acetyl-CoA synthetases are NOT found in
this structure:
a. Peroxisomes
b. Outer mitochondrial membrane
c. Endoplasmic reticulum
d. Cytosol
d. Cytosol
Acyl-CoA synthetases are found in the
endoplasmic reticulum, peroxisomes, and on
the outer membrane of mitochondria
39
Carnitine is formed by:
a. Lysine and methionine
b. Glycine and arginine
c. Proline and hydroxyproline
d. Aspartate and glutamate
a. Lysine and methionine
Trimethyllysine and γ-butyrobetaine
hydroxylases are required for the synthesis of
carnitine. Trimethyllysine from methionine and
lysine.
40
Beta oxidation requires all these, except:
a. NAD
b. CoA
c. NADP
d. FAD
c. NADP
Each step in fatty acid oxidation involves
acyl-CoA derivatives, is catalyzed by separate
enzymes, utilizes NAD+ and FAD as coenzymes,
and generates ATP. It is anaerobic process,
requiring the presence of oxygen.
41
Ketone bodies are synthesized in:
a. Brain
b. Adipose tissue
c. Liver
d. Muscles
c. Liver
When this pathway is proceeding at a high
rate, three compounds, acetoacetate, D-3-
hydroxybutyrate, and acetone, known
collectively as ketone bodies, are produced in
the liver.
42
Which of the following are TRUE regarding
beta-oxidation?
a. Requires beta-ketoacyl CoA as substrate
b. Forms CoA thioesterase
c. Requires GTP for its activity
d. Yields acetyl-CoA as product
d. Yields acetyl-CoA as product
Acetyl-CoA is both the endpoint of fatty
acid catabolism and the starting substrate for the
fatty acid synthesis,
43
Rate-limiting step for the synthesis of free
fatty acid.
a. Acetyl-CoA carboxylase
b. Carbamoyl PhosphateSynthetase I
c. Acetyl-CoA decarboxylase
d. Carbamoyl Phosphate Synthetase II
a. Acetyl-CoA carboxylase
Acetyl-CoA carboxylase is the most
important enzyme in the regulation of
lipogenesis.
44
NADPH is from what pathway
Pentose phosphate pathway
The main source of NADPH for lipogenesis
is the pentose phosphate pathway. The oxidative
reactions of the pentose phosphate pathway are
the chief source of hydrogen required for the
synthesis of fatty acids.
45
True of Fatty acid multienzyme complex
except
a. Dimer composed of 2 identical monomer
b. C-terminal a-ketoacyl
b. C-terminal a-ketoacyl
The complex is
a dimer of two identical polypeptide monomers
in which six enzymes and the ACP are linked in
the primary structure in the sequence shown. X-
ray crystallography of the three-dimensional structure has demonstrated that the two
monomers in the complex are arranged in an X-
shape.
N terminal: Ketoacyl synthase
C terminal: thioesterase
46
Elongation of fatty acid occur in what organ
Endoplasmic reticulum
47
Cofactor of acetyl coa to malonyl coa
biotin
Acetyl-Coa carboxylase
has a requirement for the B vitamin biotin and is
a multienzyme protein containing biotin, biotin
carboxylase, biotin carboxyl carrier protein, and
carboxyl transferase.
48
Inc concentrations of sphingomyelins
Niemann-Pick disease
49
Farber Disease
Ceramidase
50
Phospholipase A2 removes FA synthesis
from lecithin to form
a. Phosphatidic acid
b. Lysolecithin or lysophosphatidylcholine
c. Lecithin granules
d. Glyceryl phosphate
b. Lysolecithin or lysophosphatidylcholine
51
Serves as precursor.... glycerol moeity....
glycerol ether phospholipids like plasmalogens
& PAF
Dihydroxyacetone phosphate
Phosphoglycerols
containing an ether link (-C-O-C-). the best
known of which are plasmalogens and PAF, are
derived from the dihydroxyacetone phosphate.
52
Deficiency in lung surfactant causes
respiratory distress syndrome. Which
phospholipid is most likely involved?
Dipalmitoyl-phosphatidylcholine
Lung surfactant is mainly
composed of lipids with some proteins and
carbohydrates and prevents the alveoli from
collapsing. The phospholipid dipalmitoyl
phosphatidylcholine decreases surface tension
at the air-liquid interface and thus greatly
reduces the work of breathing.
53
38.Triacylglycerols in plasma lipoproteins are
hydrolyzed by
a. Lipoprotein lipase
b. Pancreatic lipase
c. Lingual lipase
d. Colipase
a. Lipoprotein lipase
Triacylglycerols of Chylomicrons & VLDL
Are Hydrolyzed by Lipoprotein Lipase toForm
Remnant Lipoproteins. While, hepatic lipase is
involved in chylomicron remnant and HDL
metabolism.
54
VLDL apolipoproteins include:
B-100, C-1, C-2, C-3
55
40.Which of the following has the least
cholesterol
a. Milk
b. Meat
c. Cheese
d. Butter
a. Milk
56
Regulation of intracellular cholesterol is
upregulated by this transcription factor
a. HMG CoA
b. SREBP
c. Sterol proteolytic enzymes
d. HMG CoA reductase
b. SREBP
Acetoacetyl-CoA condenses with a
further molecule of acetyl-CoA catalyzed by
HMGCoA synthase to form HMG-CoA, which is
reduced to mevalonate by NADPH in a reaction
catalyzed by HMG-CoA reductase. This last
step is the principal regulatory step in the
pathway of cholesterol synthesis and is the site
of action of the most effective class of the cholesterol-lowering drugs, the statins, which
are HMG-CoA reductase inhibitors.
57
Not apolipoprotein function
a. Enzyme inhibitor
b. Form part of lipoprotein structure
c. Enzyme cofactor
d. Control lipolysis
d. Control lipolysis
Apolipoproteins carry out several roles:
(1) they can form part of the structure of the
lipoprotein; (2) they are enzyme cofactors, for
example, C-II for lipoprotein lipase, A-I for
lecithin:cholesterol acyltransferase (LCAT), or
enzyme inhibitors, for example, apo A-II and
apo C-III for lipoprotein lipase, apo C-I for
cholesteryl ester transfer protein; and (3) they
act as ligands for interaction with lipoprotein
receptors in tissues.
58
True of the alcohol fatty liver:
The fat accumulation in the liver is
caused by a combination of impaired fatty acid
oxidation and increased lipogenesis, which is
thought to be due to changes in the
[NADH]/[NAD+] redox potential in the liver,
and also to interference with the action of
transcription factors regulating the expression
of the enzymes involved in the pathways
59
Least likely true of phenylketonuria
a. Diet low in phenylalanine can prevent
mental retardation of PKU
b. Type 1 and 2 – defects in
dihydrobiopterin reductase
c. Type 3 and 4 – defects in
dihydrobiopterin biosynthesis
d. DNA probe facilitate prenatal
diagnosis of defects
Hyperphenylalaninemias arise from
defects in phenylalanine hydroxylase, (type I,
classic phenylketonuria[PKU], frequency 1 in
10,000 births), in dihydrobiopterin reductase
(types II and III), or in dihydrobiopterin
biosynthesis (types IV and V)
60
Precursor of thyroxine
a. Glutamate
b. Tyrosine
c. Phenylalanine
d. Serine
b. Tyrosine
The amino acid tyrosine is the starting
point in the synthesis of both the
catecholamines and thyroid hormones
tetraiodothyronine (thyroxine; T4) and
triiodothyronine (T3)
61
Not a catecholamine
a. Dopamine
b. Noradrenaline
c. Adrenaline
d. Histamine
d. Histamine
Three amines—dopamine,
norepinephrine, and epinephrine—are
synthesized from tyrosine in the chromaffin
cells of the adrenal medulla.
62
The free fatty acid in the blood are:
A. Mainly bound to b lipoprotein
B. Stored as fat droplets
C. Bound to serum albumin
D. Metabolically inactive
C. Bound to serum albumin
Release of free fatty acids into the plasma, where
they are found combined with serum albumin
63
The beta-oxidation of odd-carbon fatty acid
chain gives which substrate?
A. Acetyl CoA
B. Proprionyl CoA
C. Succinyl CoA
D. Malonyl CoA
B. Proprionyl CoA
Propionyl-CoA instead of acetylCoA is used as
the primer for the synthesis of long-chain
fatty acids with an odd number of carbon atoms.
64
Which of the following has the correct order
from lowest to highest density?
A. Chylomicrons, VLDL, IDL, LDL
B. LDL, IDL, VLDL, Chylomicrons
C. Chylomicrons, IDL, VLDL, LDL
D. VLDL, IDL, LDL, Chylomicrons
A. Chylomicrons, VLDL, IDL, LDL
65
LCAT activity is associated with which
lipoprotein complex?
A. IDL
B. Chylomicrons
C. VLDL
D. HDL
D. HDL
HDL3, generated from discoidal HDL by the
action of LCAT, accepts cholesterol from the
tissues via the SR-B1 and the cholesterol is then
esterified by LCAT, increasing the size of the
particles to form the less dense HDL2.
66
Which lipoprotein removes cholesterol from
the body?
A. IDL
B. Chylomicrons
C. VLDL
D. HDL
D. HDL
In the tissues, on the other hand, SR-B1 mediates
the acceptance of cholesterol effluxed from the
cells by HDL, which then transports it to the liver
for excretion via the bile (either as cholesterol or after conversion to bile acids) in the process
known as reverse cholesterol transport.
67
Which of the following best describes
cholesterol?
A. Its main metabolic end product is bile acid
B. Excretion is through feces
C. A meal rich in unsaturated fats will help lower
cholesterol plasma levels in blood
D. Squalene is the hydrocarbon formed in
cholesterol synthesis
C. A meal rich in unsaturated fats will help lower
cholesterol plasma levels in blood
One of the mechanisms by which unsaturated
fatty acids lower blood cholesterol levels is by
the upregulation of LDL receptors on the cell
surface
68
Which of the following lipoproteins would
contribute to a measurement of plasma
cholesterol in a normal individual following a 12
hr fast?
A. Chylomicrons
B. HDL
C. LDL
D. Both LDL and VLDL
D. Both LDL and VLDL
69
Committed step in cholesterol synthesis:
mevalonate from HMG Co
70
Triacylglycerols in plasma lipoproteins are
hydrolyzed by
A. Lipoprotein lipase
B. Pancreatic lipase
C. Lingual lipase
D. Colipase
A. Lipoprotein lipase
Triacylglycerols of Chylomicrons & VLDL Are
Hydrolyzed by Lipoprotein Lipase to Form
Remnant Lipoproteins
71
Conversion of acetyl coa to malonyl coa
requires
A. H2O
B. NADPH
C. Biotin
D. Folic acid
C. Biotin
Bicarbonate as a source of CO2 is required in the
initial reaction for the carboxylation of acetyl-
CoA to malonyl-CoA in the presence of ATP and
acetyl-CoA carboxylase. This enzyme has a major
role in the regulation of fatty acid synthesis (see
below). Acetyl-CoA carboxylase has a
requirement for the B vitamin biotin and is a
multienzyme protein containing biotin, biotin
carboxylase, biotin carboxyl carrier protein, and
a carboxyl transferase, as well as a regulatory
allosteric site.
72
Not apolipoprotein function
A. Enzyme inhibitor
B. Form part of lipoprotein structure
C. Enzyme cofactor
D. Control lipolysis
D. Control lipolysis
Apolipoproteins carry out several roles:
(1) they can form part of the structure of the
lipoprotein
(2) they are enzyme cofactors or enzyme
inhibitors
(3) they act as ligands for interaction with
lipoprotein receptors in tissues
73
Amino acid that can be converted to
tyrosine if with ample supply
A. Leucine
B. Phenylalanine
C. Arginine
D. Glycine
B. Phenylalanine
Phenylalanine hydroxylase converts
phenylalanine to tyrosine. If the diet contains
adequate quantities of the nutritionally essential
amino acid phenylalanine, tyrosine is
nutritionally nonessential.
74
True for Urea Synthesis: Has 5 steps
75
Disorder of branched chain amino acid:
maple syrup urine disease (branched-chain ketonuria, or MSUD)
76
Branch chain Amino Acid:
isoleucine, leucine, and valine
THE INITIAL REACTIONS ARE COMMON TO ALL
THREE BRANCHED-CHAIN AMINO ACIDS
The first three reactions of the catabolism of
isoleucine, leucine, and valine are analogous to
reactions of fatty acid catabolism.
77
Defective enzyme in classic
hyperphenylalaninemias
A. Tyrosine aminotransferase
B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Tryptophan pyrrolase
B. Phenylalanine hydroxylase
Hyperphenylalaninemias arise from defects in
phenylalanine hydroxylase, type I, classic
phenylketonuria [PKU].
78
Precursor of allergic factor and gastric
secretion (histamine)
A. Glutamine
B. Histidine
C. Phenylalanine
D. Cysteine
B. Histidine
Decarboxylation of histidine to histamine is
catalyzed by the pyridoxal 5′-phosphate-
dependent enzyme histidine decarboxylase
79
Precursor of norepinephrine
A. Cysteine
B. Tryptophan
C. Serine
D. Tyrosine
D. Tyrosine
Neural cells convert tyrosine to epinephrine and
norepinephrine.
80
Not involved in creatine synthesis
A. Glycine
B. Serine
C. Arginine
D. Methionine
B. Serine
Glycine, arginine, and methionine all participate
in creatine biosynthesis.
81
Matching Type
A. Fumarylacetoacetate hydrolase
B. tyrosine aminotransferase
C. cystathionine B synthase
D. p-hydroxyphenylpyruvate hydroxylase
E. histidine ammonia lyase
91. Homocystinuria: cystathionine B synthase
92. Type 1 tyrosinemia: Fumarylacetoacetate
hydrolase
93. Type 2 tyrosinemia: tyrosine
aminotransferase
94. Neonatal tyrosinemia: p-
hydroxyphenylpyruvate hydroxylase
95. Histidinemia: histidine ammonia lyase
82
A. Glucogenic
B. Ketogenic
C. Both
96. Alanine: Glucogenic
97. Lysine: Ketogenic
98. Leucine: Ketogenic
99. Tyrosine: Both
100. Valine: Glucogenic
83
Oxidation of palmitic acid (C16) involves ______
rounds of B-oxidation and yields _____molecules of
acetyl-CoA.
8, 8
7, 8
7, 7
16, 8
7, 8
seven cycles needed for the breakdown of the C16 fatty
acid, palmitate, to acetyl-CoA (7 × 4 = 28). A total of 8 mol of
acetyl-CoA is formed, and each gives rise to 10 mol of ATP on oxidation in the citric acid cycle, making 8 × 10 = 80 mol
84
Which of the following yields the most energy per
gram when oxidized?
protein
starch
fat
glycogen
fat
fatty acids yield the most ATP on an energy per gram basis, when they are completely oxidized to
85
Very long chain fatty acids (C20, C22) are oxidized in
which type of organelle?
peroxisomes
lysosomes mitochondria
endoplasmic reticulum
peroxisomes
Peroxisomes Oxidize Very Long Chain FAs
A modified form of β-oxidation is found in peroxisomes and
leads to the formation of acetyl-CoA and H2O2 (from the
flavoprotein-linked dehydrogenase step), which is broken
down by catalase. Thus, the dehydrogenation in peroxisomes
is not linked directly to phosphorylation and the generation of
ATP. The system facilitates the oxidation of very long chain fatty acids (eg, C20, C22)
86
Which of the following statements BEST DESCRIBES
the regulation of ketogenesis?
- Overproduction of ketone bodies is due to excessive
carbohydrates.
- This is the outcome of excessive utilization of
fatty acids to meet the energy requirements.
- Glucagon inhibits ketogenesis while, insulin
stimulates it.
- High concentration of oxaloacetate favors
ketogenesis
- This is the outcome of excessive utilization of
fatty acids to meet the energy requirements
Regulation of Ketogenesis happens in 3 crucial steps
Excessive utilization of FFA leads to production of more acetylCoA entering the ketogenic pathway. (Figure 22-9)
87
High concentration of oxaloacetate favors which
pathway?
Glycolysis HMP shunt
TCA cycle
Glycogenolysis
TCA cycle
condensation of acetyl-CoA with oxaloacetate in the citric acid cycle within mitochondria,
88
Ketone bodies are synthesized in:
muscles
adipose tissue
brain
liver
liver
KETOGENESIS OCCURS WHEN THERE IS A HIGH RATE OF FATTY ACID OXIDATION IN THE LIVER
89
This lipid is derived from free fatty acids through
esterification after an uptake by the liver.
a. cholesterol
b. triacylglycerol
c. sphingolipid
d. lipoprotein
a. cholesterol
Chylomicron remnants are taken up by the liver by
receptor-mediated endocytosis, and the
cholesteryl esters & triacylglycerol are hydrolyzed
and metabolized. Triacylglycerol is composed of
three fatty acids esterified to a glycerol molecule
90
Which is not a characteristic feature of the
fatty acid synthase multienzyme complex?
a. dimer of 2 polypeptide monomer
b. complex arranged in an X-shape as identified
by an X-ray crystallography
c. the enzyme at the primary structure at the
C-terminus is ketoacyl synthase
d. has an acyl carrier protein attached to the
primary structure
c. the enzyme at the primary structure at the
C-terminus is ketoacyl synthase
the enzyme at the primary structure at the C-terminus is thioesterase
91
Ketone bodies are formed from acetyl-CoA which is
directly produced from:
a. alanine
b. lysine
c. phenylalanine
d. isoleucine
b. lysine
92
In extramitochondrial fatty acid synthesis, one of
the following cofactors or their derivatives is
necessary for the conversion of acetyl CoA to
malonyl CoA
a. FMN
b. biotin
c. FAD
d. ACP
b. biotin
Acetyl CoA carboxylase converts acetyl CoA to
malonyl CoA. It has a requirement for the B vitamin
biotin and is a multienzyme protein.
93
The concentration of sphingomyelins are increased
in this disease entity.
a. Fabrile disease
b. Fabry disease
c. Niemann-Pick disease
d. Gaucher disease
c. Niemann-Pick disease
Fabry disease - alpha-galactosidase
Niemann-Pick disease - sphingomyelinase
Gaucher disease - beta-galactosidase
94
What is the correct ordering of serum lipoprotein
from the greatest to lowest density?
a. chylomicron, LDL, IDL, VLDL
b. IDL, chylomicron, LDL, VLDL
c. LDL, IDL, VLDL, chylomicron
d. VLDL, IDL, LDL, chylomicron
c. LDL, IDL, VLDL, chylomicron
Densities:
LDL - 1.019 - 1.063
IDL - 1.006 - 1.019 VLDL - 0.95 - 1.006 Chylomicron - <0.95
95
This pathway servees as the main source of NADPH
for lipogenesis
A. Beta oxidation
B. Gluconeogenesis
C. Citric Acid Cycle
D. HMP shunt
D. HMP shunt
The main source of NADPH for lipogenesis is the Pentose Phosphate Pathway. PPP is also known as Hexose monophosphate (HMP) shunt
96
The primer used for the synthesis of long-chain fatty
acids with odd number of carbon atoms
A. Malonyl CoA
B. Acetyl CoA
C. Propionyl CoA
D. Acyl CoA
C. Propionyl CoA
The Acetyl-CoA used as a primer formscarbon atoms 15 and
16 of palmitate. th addition of all the subsequent C2 units is
via the malonyl-CoA. Propionyl CoA instead of acetyl CoA is
used as a primer for the synthesis of long chain fatty acids with an odd number of carbon atoms, which are found
particularly in ruminant fat and milk
97
Which of the ff is the 2nd step of lipogenesis?
A. Provision of acetyl-CoA and NADPH
B. Transport of acetyl-CoA from the mitochondria to
the cytosol
C. Reactions of synthesis using fatty acid
synthase complex
D. Carboxylation of acetyl-CoA to malonyl-CoA
C. Reactions of synthesis using fatty acid
synthase complex
Production of Malonyl-CoA is the initial & controlling step in
fatty scid synthesis. After the formation of malonyl-CoA, fatty acids are formed by the fatty acid synthase enzyme
complex.
98
Best describes the regulation of acetyl-CoA
carboxylase
A. Inactivated by cysteine group
B. Activated by citrate
C. Tricarboxylate transporter transports citrate from
cytosol to mitochondria
D. Inactivation is promoted by phosphorylation of
the enzyme
B. Activated by citrate
lipogenesis. It is an allosteric enzyme and is activated by
citrate, which increases in concentration in the well-fed state
and is an indicator of a plentiful supply of acetyl-CoA (Please recheck since option D is also in p.221)
rechecked: both answers are considerable.
99
Which of the ff lipoproteins would contribute to a
measurement of plasma cholesterol in a normal
individual ff a 12-hr fast?
A. Both VLDL and LDL
B. VLDL
C. LDL
D. Chylomicrons
A. Both VLDL and LDL
100
Alcoholic fatty liver is best described by this statement
A. The concomitant gout in these patients is due to
hypolacticacidemia
B. May be caused by decreased lipogenesis &
impaired fattyacid oxidation
C. There is excess production of NAD
D. (+) oxidation of ethanol by alcohol
dehydrogenase
D. (+) oxidation of ethanol by alcohol
dehydrogenase
Oxidation of ethanol by alcohol dehydrogenase leads to
excess production of NADH, which competes with reducing
equivalents from other substrates, including fatty acids, for
the respiratory chain This inhibits their oxidation and causes
increased esterification od fatty acids to form triacylglycerol,
resulting in fatty liver disease.
A. Hyperlacticacidemia decreases excretion of uric acid,
aggravating gout
B. Caused by impaired fatty acid oxidation and increased lipogenesis
C. Excess production of NADH
101
Lipase present in the stomach cannot hydrolyze fats
owing to its
A. Acidity
B. Esterification property
C. Neutrality
D. Alkalinity
A. Acidity
Digestion of Fats Occurs Mainly in the Small Intestine. A small amount of triglycerides is digested in the
stomach by lingual lipase secreted by lingual glands in the mouth and swallowed with the saliva. This amount of
digestion is less than 10 percent and is generally unimportant.
Instead, essentially all fat digestion occurs in the
small intestine as follows.
102
Triacylglycerol present in the plasma lipoproteins
are hydrolyzed by:
A. Colipase
B. Lingual lipase
C. Pancreatic lipase
D. Lipoprotein lipase
D. Lipoprotein lipase
103
A 25 y.o female has been diagnosed with lecithin:
cholesterol acyltransferase(LCAT) deficiency. In which
of the ff reactions LCAT is involved? A. uptake of cholesterol from liver cells
B. converting cholesterol to cholesterol esters
C. hydrolysis of HDL
D. transfer of cholesterol esters from HDL to VDL
B. converting cholesterol to cholesterol esters
104
Regulation of intracellular cholesterol is up regulated
by this transcription factor
A. SREBP
B. HMG-CoA
C. Na/K+ ATPase
D. Sterol proteolytic enzymes
A. SREBP
105
Match the following:
A. inhibits Tricorboxylate transporter
B. Stimulates acetyl coA carboxylase
C. inhibits acetyl coA carboxylase
D. malonyl coA
E. ATP dependent
F. palmitic acid
Acetyl coa carboxylase - D
Insulin - B
Glucagon - C
Thioesterase - A
Acyl- coA - F
106
Match the following:
A. Zellweger syndrome
B. RDS
C. Retinitis pigmentosa
D. Gaucher`s disease
E. Krabbe Disease
F. Farber Disease
DHA - C
Dipalmitoyl phosphatidylcholine - B
B-galactosidase - E
Ceramidase - F
Very long chain fatty acids - A
107
Which of the following proteins or
enzymes that when deficient, can cause
mutation implied by the chronic granulomatous disease
A. NADPH oxidase
B. Myeloperoxidase
C.
D. Glutathione peroxidase
A. NADPH oxidase
108
Which of the ff. Metabolic pathways is
crucial to the red blood cells as it
supplies reducing energy to the cell
A. Glycolysis
B. Oxidative phosphorylation
C. Pentose phosphate pathway
D. Citric acid cycle
C. Pentose phosphate pathway
109
This pathway is the alternative source of
energy (ATP) of platelets.
A. Glycolysis
B. Fatty acid beta oxidation
C. Pentose phosphate pathway
D. Ketogenesis
B. Fatty acid beta oxidation
110
Glycolytic enzymes in a eukaryotic cell
are located in the?
Cytosol
111
This statement LEAST LIKELY describes
glycolysis:
A. ADP is phosphorylated to ATP via
substrate level phosphorylation
B. The pathway oxidizes two moles of NADH to NAD+ for each mole of glucose
that enters
C. The pathway does not require oxygen
D. The pathway requires two moles of
ATP to get started catabolizing each
mole of glucose
B. The pathway oxidizes two moles of NADH to NAD+ for each mole of glucose that enters
112
Which of the following enzymes is the
major energy generating step during
glycolysis
A. Phosphofructokinase
B. Pyruvate kinase
C.Glyceraldehyde-3-Phosphate
D. Phosphoglycerate kinase
C.Glyceraldehyde-3-Phosphate
113
Glucose from the breakdown of glycogen
through hydrolysis is obtained in what
organ?
A. Liver
B. Muscles
C. Kidneys
D. Pancreas
A. Liver
114
In glycogen synthase reaction, precursor
of glycogen:
A.Glucose-6-phosphate
B.UTP-glucose
C.Glucose-1-phosphate
D.UDP-glucose
D.UDP-glucose
115
he first irreversible step of glycolysis
is catalyzed by this enzyme
a. Hexokinase
b. Phosphofructokinase
c. Glucokinase
d. Pyruvate kinase
a. Hexokinase
116
Cleave of your fructose 1,6
bisphosphate yields
a. Aldose, ketose
b. 2 aldose
c. 2 ketose
d. Only a ketose
a. Aldose, ketose
Aldose DHAP ketose G3P
117
Substrate used in the last step of
glycolysis:
A. Pyruvate
B. GA3P
C. 1,3-BPG
D. PEP
D.PEP( phosphoenolpyruvate)
118
Pyruvate, the end product of glycolysis,
enters the citric acid cycle after is has
been converted to
A. Acetic acid
B. Lactic acid
C. Acetaldehyde
D. Acetyl-CoA
D. Acetyl-CoA
119
Carrier protein which transports pyruvate
through the mitochondrial matrix
A. NADH
B. Coenzyme A
C. NADPH
D. Succinyl CoA
B. Coenzyme A
120
BEST DESCRIBES the rate-limiting
enzymes of glycogenolysis.
A. Named glycogen synthase
B. Catalyze the phosphorylitic cleavage
of the 1->4 linkages of glycogen to G3P
C. Requires glycogenesis as its
coenzyme
D. Has different isoenzyme encoded by
different genes
D. Has different isoenzyme encoded by
different genes
121
Glycolytic enzymes in eukaryotic cells
are located in
A. Plasma membrane
B. Mitochondrial matrix
C. Cytosol
D. Intermembrane space
C. Cytosol
122
LESS LIKELY describes glycolysis:
A. ADP is phosphorylated to ATP at
substrate level phosphorylation
B. Pathway oxidizes 2 NADH to NAD+
for each mole of glucose that enters
C. Does not require oxygen
D. Pathway required 2 ATP to start
catabolizing each mole of glucose
B. Pathway oxidizes 2 NADH to
NAD+ for each mole of glucose
that enters
*Should be reduces NAD+ to NADH
123
Enzyme involved in the major energy
generating step in glycolysis:
A. Phosphofructokinase
B. Pyruvate kinase
C. GA3P
D. Phosphoglycerate kinase
C. GA3P
124
Glucose, from glycogen through
hydrolysis, can be found in
A. Liver
B. Muscle
C. Kidney
D. Pancreas
A. Liver
125
What is the precursor of glucose
A. Glucose 1 phosphate
B. UDP- glucose
C. Glucose-6 phosphate
D. Glucose-6 phosp
C. Glucose-6 phosphate
126
In the liver, cAMP independent activation
of glycogenolysis needs the following
hormones, EXCEPT:
A. Epinephrine
B. Angiotensin II
C. Glucagon
D. Vasopressin
C. Glucagon
127
Glycogenin is needed to create an initial
short glycogen chain. These amino acid
residues serves as an anchor for the
terminal chain of glycogen:
A. Serine
B. Tyrosine
Glycogenin is needed to create an initial
short glycogen chain. These amino acid
residues serves as an anchor for the
terminal chain of glycogen:
A. Serine
B. Tyrosine
C. Glycine
D. Leucine
B. Tyrosine
128
What's faster when needing glucose
A. Gluconeogenesis
B. Gluconeogenesis
C. Glycogenolysis - KANI
D. Glycolysis
C. Glycogenolysis
129
Makes up the bond in glycogen branches
A. Phospodiester
B. Covalent
C. 1,4-glycosidic
D. 1,6-glycosidic
D. 1,6-glycosidic
130
which enzyme is activated by glucagon
a. glycogen synthase
b. phosphoenolpyruvate carboxykinase
c. phosphofructokinase 1
d. hexokinase
b. phosphoenolpyruvate carboxykinase
131
The metabolic function of PPP is
a. ADP biosynthesis
b. i forgot huu saarry
c. oxidation-reduction formation of h20
d. generate nadph and pentoses for the
biosynthesis of fatty acid and nucleic acid
d. generate nadph and pentoses for the
biosynthesis of fatty acid and nucleic acid
132
LEAST likely describes PPP
A. Occurs in the cytosol
B. Oxygenation occurs by dehydration of
NAD+ to act as oxygen acceptor
C. Does not require ATP
D. Has 2 stages, irreversible and
substrate
B. Oxygenation occurs by
dehydration of NAD+ to act as
oxygen acceptor
133
increase in insulin release
1. Fed
2. Fasting
1. Fed
134
increase in glycogen synthesis
1. Fed
2. Fasting
1. Fed
135
increase in glucagon release
1. Fed
2. Fasting
2. Fasting
136
inhibition of lipogenesis
1. Fed
2. Fasting
2. Fasting
137
gluconeogenesis
1. Liver
2. Kidney
1. Liver
2. Kidney
138
Beta oxidation
1. Liver
2. Kidney
1. Liver
139
Plasma Proteins
1. Liver
2. Kidney
1. Liver
140
Glycerol kinase
1. Liver
2. Kidney
1. Liver
2. Kidney
141
Morse type: Cause and effect
A. Both statements are true and are
related
B. Both statements are true but unrelated
C. Statement 1 is true, statement 2 is
false
D. Statement 1 is false, statement 2 is
true
E. Both statements are false
A - Water soluble products of digestion are
transported directly to the liver via
hepatic portal vein because the liver
regulates the concentration of glucose
and amino acids to other tissues
142
A - In fasting state, glucose is spared for rbc
and brain because they primarily use
glucose as metabolic fuel
D - Most amino acids undergo glycolysis
from TAG because products of digestion
are used to synthesize complex
macromolecules
143
A - ATP is the energy currency of the cell
because of its high energy potential
where ATP becomes
A - Exergonic reaction, spontaneous energy,
loss of free energy BECAUSE negative
free energy
144
C - Car exhaustion impairs the activity of
ETC because carbon oxidase inhibits
cytochrome monoxide
E - Cytochrome P450 involved in ATP
Synthesis. Citric acid cycle requires NAD
and NADP
145
A - Cytochrome P450 in steroidogenic
organs eg. Testis because they are
involved in steroid synthesis.
146
This monosaccharide is present in
the synthesis of N-linked glycoproteins
but not in mature glycoproteins.
A. Galactose
B. Glucose
C. Mannose
D. Sialic acid
A. Glucos
147
Comprises major classes of
membrane and circulating
glycoproteins.
A. O-gly
B. N-gly
C. GPI-anchored
D. Galactose-histidine-lysine
B. N-gly
148
Which of the following is a substrate of
N-glycosidic (...)
A. UDP-GalNac, P-dolichol O
glycosidic
B. GDP-Man, P-dolichol
C. UDP-GlcNAc, P-dolichol
D. CMP-NeuAc, P-dolichol
C. UDP-GlcNAc, P-dolichol
149
Proteins involved in cell membrane
transport and adhesion and are
important for stability and integrity
have this glycoprotein.
A. O linked
B. N linked
C. GPI-anchored
D. Galactose-Histidine-Lysine
glycoprotein
C. GPI-anchored
150
Degenerative and lifestyle diseases
are caused by the body’s interaction
with these molecules.
A. Sugars
B. Proteins
C. Oxygen Radicals
C. Oxygen Radicals
151
Cancer cells are believed to possess
this glycoprotein thus enabling them to
invade other cells and tissues in the
body
A. Selectin
B. Integrin
C. Calnexin
D. Laminin
A. Selectin
integrin - adhesion of neutrophils to the
endothelium
calnexin - chaperone protein in the endoplasmic
reticulum membrane; which prevents a
glycoprotein from aggregating
laminin - congenital muscular dystrophies
152
This lipid has the fatty acid esterified
with a high molecular weight alcohol
instead of glycerol
A. Derived lipids
B. Waxes
C. Oils
D. Neutral lipids
B. Waxes
153
The major fat in adipose tissues in
mammals
A. Triacylglycerol
B. Phospholipids
C. Glycolipids
D. Cholesterol
A. Triacylglycerol
154
Energy that is generated from metabolic fuels during respiration but is not captured
in the ATP formation is released as?
a. CMP
b. Carbon dioxide
c. Oxygen
d. Heat
d. Heat
155
The first law of thermodynamics states that?
A. Amount of work in a system approaches a constant value as temperature
approaches zero.
B. In a spontaneous reaction, heat energy increases the rate of molecular
collision
C. Energy can neither be created nor destroyed.
D. As energy is transferred or transformed, more and more of it is wasted.
C. Energy can neither be created nor destroyed
156
This enzyme is active in tissues that are involved in eicosanoid metabolism.
a. Peroxidase
b. Catalase
c. Oxidase
d. Reductase
a. Peroxidase
157
A 23-year-old man has been vigorously working on the yard and begins to feel
slightly light-headed from hypoglycemia. He drinks a can of soda and is aware of the
competition for the sugar to be stored in his liver as glycogen versus used as energy
in his muscles. What is the best explanation regarding the fate of the glucose in the
soda?
Group of answer choices
a. The lower Km of hexokinase compared with the Km of glucokinase will
tilt the glucose towards glycolysis.
b. The glucose will be equally used by the muscle for metabolism and the liver
for glycogen storage.
c. The bolus of glucose via the soda will lead to a higher glucose level, inducing
the storage of the glucose into glycogen in the liver.
d. The muscle is using high levels of glucose, leading to an increased level of
glucose-6-phosphate thus inhibiting glucokinase.
a. The lower Km of hexokinase compared with the Km of glucokinase will
tilt the glucose towards glycolysis.
158
A 64-years-old man is presented to his family doctor with complaints of frequent
episodes of dizziness and of numbness in his legs. During a routine history and
physical examination, the doctor finds that the patient leads a sedentary lifestyle, is
obese, and has hypertension. The patient was asked to return to the clinic 1 week later
in the fasting state, during which time a blood specimen is obtained, and a glucose
tolerance test is performed. Humoral analysis reveals fasting hyperglycemia,
hyperinsulinemia, dyslipidemia, and glucose tolerance. The diagnosis is type 2
diabetes mellitus. Alteration in the substrate metabolism within which of the following
organs can be a cause for the observed humoral analysis?
Group of answer choices
a. Heart
b. Spleen
c. Brain
d. Liver
e. Kidney
d. Liver
159
True for the overall equation of glycolysis from glucose to lactate:
Group of answer choices
a. Glucose + NADPH + CoA → 2 Lactate + NADH + H + CO2
b. Glucose + 2 ATP + 2 Pi → 2 Lactate + 2 ADP + 2 H20
c. Glucose + NAD + CoA → Acetyl-CoA + NADH + H + CO2
a. Glucose + NADPH + CoA → 2 Lactate + NADH + H + CO2
160
In glycolysis, the following occurs in the absence of oxygen EXCEPT:
Group of answer choices
a. NADH in reoxidized by reducing lactate to Pyruvate, so permitting glycolysis.
b. Limits the amount of ATP produced per mole of glucose oxidized.
c. Impaired mitochondrial reoxidation of NADH.
d. Lactic acid accumulation
c. Impaired mitochondrial reoxidation of NADH.
161
What sugar is synthesized from glucose in the lactating mammary gland and in
other tissues where it is required for the synthesis of glycolipids, proteoglycans, and
glycoproteins.
A. Maltose
B. Galactose
C. Fructose
D. Sucrose
E. Glucose
B. Galactose
162
It is a rare benign hereditary condition, which is due to the lack of xylulose
reductase in the body:
A. G6PD Deficiency
B. Essential Pentosuria
C. Hemolytic Anemia
D. Essential Fructosuria
E. Galactosemias
B. Essential Pentosuria
163
What enzyme catalyzes the removal of H2O2 in conjunction with reduced
glutathione:
A. Glutathione dehydrogenase
B. Glutathione reductase
C. UDPGlc peroxidase
D. UDPGlc reductase
E. Glutathione peroxidase
E. Glutathione peroxidase
164
In the non-oxidative phase of the Pentose phosphate pathway. This enzyme
catalyzes the transfer of a three-carbon dihydroxyacetone moiety from the ketose
sedoheptulose-7-phosphate:
A. Hexokinase
B. Transaldolase
C. Transketolase
D. Transaminase
B. Transaldolase
165
The capacity of the tubular system to reabsorb glucose is limited to a rate of
about:
A. 2 mmol/sec
B. 4 mmol/L
C. 2 mmol/min
D. 10 mmol/min
E. 10 mmol/L
C. 2 mmol/min
166
The oxidation deamination of the amino acid alanine in the liver produces:
A. One molecule of pyruvic acid and another amino acid
B. One molecule of pyruvic acid and a molecule of water
C. One molecule of pyruvic acid and a molecule of ammonia
D. One molecule of pyruvic acid and a molecule of carbon dioxide
E. One molecule of pyruvic acid and a molecule of lactate
C. One molecule of pyruvic acid and a molecule of ammonia
167
Liver glycogen breakdown is stimulated by:
A. Insulin
B. Glucagon
C. Insulin & Adrenaline
D. Adrenaline
E. Glucagon & Adrenaline
E. Glucagon & Adrenaline
168
In fasting states, the following enzyme is/are down-regulated:
A. Phosphoenolpyruvate carboxykinase
B. Pyruvate Kinase
C. Glucose-6-phosphatase
D. Pyruvate carboxylase
B. Pyruvate Kinase
169
In fasting states, the following enzymes are upregulated EXCEPT:
A. Pyruvate Kinase
B. Glucose-6-phosphatase
C. Phosphoenolpyruvate carboxykinase
D. Pyruvate carboxylase
A. Pyruvate Kinase
170
Glucose enters muscle cells mostly by:
A. Simple diffusion
B. Co-transport with sodium
C. Active transport
D. Facilitated diffusion using specific glucose transporter
E. Co-transport with amino acid
D. Facilitated diffusion using specific glucose transporter
Glucose enters the muscle cell via facilitated diffusion
through the GLUT4 glucose transporter which
translocates from intracellular storage depots to the plasma
membrane and T-tubules upon muscle contraction.
171
The enzymes of glycolysis are located in the:
A. Nucleus
B. Lysosomes
C. Cytoplasm
D. Interstitial Fluid
E. Mitochondria
E. Mitochondri
Krebs: inner mitochondrial membrane
PPP: cytosol
172
The conversion of one molecule of glucose to two molecules of pyruvate results
in the net formation of:
A. thirty-nine molecules of ATP
B. Three molecules of ATP
C. Six molecules of water
D. thirty-eight molecules of ATP
E. Two molecules of ATP
E. Two molecules of ATP
173
In general, the higher the intensity of exercise, the greater the proportional
contribution of:
A. The TCA cycle (Krebs’ cycle) to the production of ATP
B. Anaerobic energy production
C. Aerobic energy production
D. Electron transfer chain to the production of ATP
E. Fat oxidation
C. Aerobic energy production
174
Anaerobic metabolism refers to the generation of ATP:
A. Without the use of glycogen
B. by the conversion of pyruvate to lactate
C. in the absence of available pyruvate
D. Without the involvement of ADP
E. Without the use of oxygen
E. Without the use of oxygen
175
In glycogenolysis, what enzyme catalyzes the rate-limiting step in
glycogenolysis?
A. Branching enzyme
B. Glycogen synthase
C. Glycogen phosphorylase
D. Glucogenin
E. Debranching enzyme
C. Glycogen phosphorylase
176
A young man with normocytic anemia, jaundice, and splenomegaly was
diagnosed as having RBC pyruvate kinase deficiency after a peripheral blood smear
showed spiculated cells. Because pyruvate kinase is abnormal in this patient, not
only is less pyruvate made but intermediates above pyruvate in the glycolytic
pathway also build up, slowing the pathway. Which of the following products may
not be made in the appropriate amounts in the RBC because of the deficiency of
pyruvate?
A. Glucose
B. Lactate
C. Oxaloacetate
D. Acetyl-CoA
B. Lactate
The RBC has no mitochondria so glucose cannot be made from
pyruvate or acetyl-CoA or oxaloacetate. The RBC does have
lactate dehydrogenase and conversion to lactate depends on pyruvate levels.
177
In glycogen synthesis, what enzyme catalyzes the formation of a glycoside bond
between C-1 of the glucose of UDPGlc and C-4 of a terminal glucose residue of
glycogen?
A. Branching enzyme
B. Glycogen phosphorylase
C. Glucogenin
D. Debranching enzyme
E. Glycogen synthase
E. Glycogen synthase
is a glycosyltransferase that catalyzes the elongation of the
glycogen chain by incorporating glycosyl residues from UDP-
glucose to the growing glycogen strand, forming α-1,4-glycosidic linkages with the release of UDP.
178
What glycogen storage disease is deficient in the enzyme cAMP-dependent
protein kinase A?
A. Type 0
B. Type VIII
C. Type Ib
D. Type X
E. Type IX
D. Type X
179
What glycogen storage disease is deficient in the enzyme lysosomal
glucosidase?
A. Andersen disease
B. Taraui disease
C. Hers disease
D. Pompe disease
E. Cori disease
D. Pompe disease
180
What glycogen storage disease is deficient in the Branching enzyme?
A. Cori disease
B. Hers disease
C. Taraui disease
D. Andersen disease
E. Pompe disease
D. Andersen disease
181
In glycogen synthesis, what enzyme transfers a part of the 1 → 4 chains to a
neighboring chain to form a 1 → 6 linkage?
A. Debranching enzyme
B. Glycogen phosphorylase
C. Glycogen synthase
D. Glucogenin
E. Branching enzyme
E. Branching enzyme
182
The initial step of glycogen synthesis is involved with this protein, which
catalyzes the transfer of glucose residue to form the glycogen primer:
A. Aldolase
B. Enolase
C. Calmodulin
D. Glycogenin
E. Glucogenin
D. Glycogenin
183
Glucose-6-phosphate is an important compound at the junction of several
metabolic pathways EXCEPT:
A. Pentose Phosphate Pathway
B. Glycogenesis
C. Citric Acid Cycle
D. Glycolysis
E. Gluconeogenesis
C. Citric Acid Cycle
184
Pyruvate dehydrogenase complex is composed of the following three enzymes:
A. Pyruvate Dehydrogenase, Dihydrolipoyl transacetylase, Dihydrolipoyl
dehydrogenase
B. Dihydrolipoyl dehydrogenase, Pyruvate Kinase, Pyruvate Transketolase
C. Pyruvate Dehydrogenase, Pyruvate Kinase, Pyruvate Transketolase
D. Pyruvate Kinase, Pyruvate Dehydrogenase, Hexokinase
E. Phosphofructokinase, Aldolase, Transketolase
A. Pyruvate Dehydrogenase, Dihydrolipoyl transacetylase, Dihydrolipoyl dehydrogenase
185
What are the three enzymes catalyzing the nonequilibrium reactions of glycolysis?
Group of answer choices
a. Hexokinase, Pyruvate Kinase, Phosphofructokinase
b. Enolase, Hexokinase, Glucokinase
c. Pyruvate Kinase, Pyruvate Dehydrogenase, Hexokinase.
d. Phosphofructokinase, Aldolase, Transketolase
e. Phosphofructotransferase, Glucokinase, Pyruvate Hydrolase
a. Hexokinase, Pyruvate Kinase, Phosphofructokinase
186
In glycolysis, the following occurs in the absence of oxygen EXCEPT:
Group of answer choices
a. NADH in reoxidized by reducing lactate to Pyruvate, so permitting glycolysis.
b. Limits the amount of ATP produced per mole of glucose oxidized.
c. Impaired mitochondrial reoxidation of NADH.
d. Lactic acid accumulation
c. Impaired mitochondrial reoxidation of NADH
187
True for the overall equation of glycolysis from glucose to lactate:
Group of answer choices
a. Glucose + NADPH + CoA → 2 Lactate + NADH + H + CO2
b. Glucose + 2 ATP + 2 Pi → 2 Lactate + 2 ADP + 2 H20
c. Glucose + NAD + CoA → Acetyl-CoA + NADH + H + CO2
d. Glucose + 2 ADP + 2 Pi → 2 Lactate + 2 ATP + 2 H20
a. Glucose + NADPH + CoA → 2 Lactate + NADH + H + CO2
188
Which of the following complications is less likely to occur in people with type 2
diabetes compared with those with type 1 diabetes?
Group of answer choices
a. Retinopathy
b. Hypoglycemic Coma
c. Weight gain
d. Neuropathy
e. Cardiovascular disease
b. Hypoglycemic Coma
189
A 64-years-old man is presented to his family doctor with complaints of frequent
episodes of dizziness and of numbness in his legs. During a routine history and
physical examination, the doctor finds that the patient leads a sedentary lifestyle, is
obese, and has hypertension. The patient was asked to return to the clinic 1 week later
in the fasting state, during which time a blood specimen is obtained, and a glucose
tolerance test is performed. Humoral analysis reveals fasting hyperglycemia,
hyperinsulinemia, dyslipidemia, and glucose tolerance. The diagnosis is type 2
diabetes mellitus. Alteration in the substrate metabolism within which of the following
organs can be a cause for the observed humoral analysis?
Group of answer choices
a. Heart
b. Spleen
c. Brain
d. Liver
e. Kidney
d. Liver
190
A 23-year-old man has been vigorously working on the yard and begins to feel
slightly light-headed from hypoglycemia. He drinks a can of soda and is aware of the
competition for the sugar to be stored in his liver as glycogen versus used as energy
in his muscles. What is the best explanation regarding the fate of the glucose in the
soda?
Group of answer choices
a. The lower Km of hexokinase compared with the Km of glucokinase will
tilt the glucose towards glycolysis.
b. The glucose will be equally used by the muscle for metabolism and the liver
for glycogen storage.
c. The bolus of glucose via the soda will lead to a higher glucose level, inducing the storage of the glucose into glycogen in the liver.
d. The muscle is using high levels of glucose, leading to an increased level of glucose-6-phosphate thus inhibiting glucokinase.
a. The lower Km of hexokinase compared with the Km of glucokinase will tilt the glucose towards glycolysis.
The lower Km of hexokinase compared with the Km of
glucokinase will tilt the glucose towards glycolysis.
Hexokinase is found in most tissues, and because of the very
low Km (substrate concentration at which the enzyme
achieves half maximal velocity) for glucose, it is designed to
work maximally to provide ATP for tissue even at low levels
of glucose. Hexokinase is inhibited by glucose 6-phosphate
and is most active with low levels of glucose 6-phosphate.
Glucokinase found in the liver has a high Km for glucose and is very active after a meal. The glucose in the soda would likely be used for ATP production.
191
A 17-year-old boy presents complaining of an inability to perform strenuous
exercises without bringing in painful muscle cramps and weakness. He indicated that
mild to moderate exercise resulted in no problems. When he was administered an
ischemic exercise test, his serum lactate concentration did not significantly increase.
A deficiency in which of the following enzymes is most likely the cause of the patients’
muscle cramps?
a. Glucose-6-phosphatase
b. Long Chain acyl-CoA
c. Glycogen synthase
d. Glycogen phosphorylase
e. Carnitine palmityl transferase II
d. Glycogen phosphorylase
Although a deficiency in a number of enzymes can result in exercise intolerance, the lack of an increase in serum lactate following ischemic exercise points to an inability to a defect in the breakdown of glycogen in the muscle. The muscle depends on glycogenolysis for intense exercise, and fatigue rapidly ensues when glycogen is depleted. Patients with a deficiency in the muscle isoform of glycogen phosphorylase (McArdle disease) can tolerate mild to moderate exercise, but get muscle cramps with strenuous exercise as a consequence of the lack of glycogenolysis in the muscle cell.
192
A 3-month-old infant presents with hepatosplenomegaly and failure to thrive. Liver
biopsy reveals glycogen with an abnormal, amylopectin-like structure with long outer
chains. Which of the following enzymes would most likely be deficient?
Group of answer choices
a. Branching enzyme
b. α-amylase
c. Glycogen phosphorylase
d. Glycogen synthase
e. Debranching enzyme
a. Branching enzyme
During Glycogenesis, branching enzyme creates branch points and further elongation is carried out by Glycogen synthase. In the deficiency of Branching
enzyme stored glycogen is abnormal, in the form of long polysaccharide chains with few branch points, resembling the
structure of Amylopectin, thus this defect is also called Amylopectinosis. Alpha Amylase is an enzyme for digestion of starch and glycogen. Debranching enzyme deficiency results in the accumulation of abnormal glycogen, there is an inability to remove the branch points, the resultant structure resembles Limit dextrin, and thus it is also called Limit dextrinosis. Glucose 6 phosphatase deficiency Is observed in von Gierke's diseases, a type 1 glycogen storage disease, the stored glycogen is always normal in chemistry
193
The following compounds can be synthesized by the enzyme Nucleoside
diphosphate kinases:
1. UTP
2. GTP
3. CTP
4. ATP
a. Statements 1 & 3 are correct.
b. Statements 1, 2 & 3 are correct.
c. All are correct.
d. Statements 2 & 4 are correct.
d. Statements 2 & 4 are correct.
194
Metabolic pathways that occur in the cytosol.
1. Fatty acid synthesis
2. Glycolysis
3. Pentose Phosphate Pathway
4. Beta-oxidation
a. Statements 2 & 4 are correct.
b. Statements 1, 2 & 3 are correct.
c. All are correct.
d. Statements 1 & 3 are correct.
b. Statements 1, 2 & 3 are correct.
Fatty acid synthesis- cytosol and endoplasmic reticulum
Glycolysis- cytosol
Pentose PO4 Pathway- cytosol
Beta-oxidation- mitochondria (eukaryotes)
195
Which of the following substances is still considered a major source of metabolic
fuel after a 40 hour fast?
a. Amino acids
b. Nonesterified fatty acids
c. Glucose
d. Ketone bodies
c. Glucose
196
The kidneys are involved in which of the following major metabolic pathway?
a. Amino acid metabolism
b. Beta-oxidation
c. Glycolysis
d. Gluconeogenesis
d. Gluconeogenesis
197
Match the items on the left with the correct choices on the right regarding nutrient
absorption.
Choices a::
Decrease calcium absorption
Increase calcium absorption
Decrease iron absorption
Increase iron absorption
Decrease zinc absorption
Choices b:
Milk- increased Ca absorption
Whole wheat bread- decreased Ca2+ absorption
High fat diet- decreased Ca2+ absorption
Alcohol- increased Fe2+ absorption
Ratio:
Decrease Ca2+ absorption:
1. Phytic acid
2. Increased fattyb acids
3. Intake of oxalate
Increase Fe2+ absorption
1. Vitaminc C
2. Alcohol
3. Fructose
198
Compounds capable of donating high-energy phosphates.
1. Phosphoenolpyruvate
2. Succinyl CoA
3. 1,3 Bisphosphoglycerate
4. Glucose-1,6-bisphosphate
a. Statements 1, 2 & 3 are correct.
b. Statements 2 & 4 are correct.
c. Statements 1 & 3 are correct.
d. All are correct.
c. Statements 1 & 3 are correct.
199
The primary requirement for an “activation” reaction to proceed. Thus, converting
a thermodynamically unfavorable reaction to favorable ones.
1. Phosphorylation
2. Oxidation
3. Phosphate Hydrolysis
4. Reduction
a. Statements 2 & 4 are correct.
b. Statements 1 & 3 are correct.
c. Statements 1, 2 & 3 are correct.
d. Statement 4 is correct.
b. Statements 1 & 3 are correct.
200
Reactions catalyzed by this/these enzyme/s produces hydrogen peroxide:
1. Catalase
2. Dehydrogenase
3. Peroxidase
4. Oxidase
a. Statements 2 & 4 are correct.
b. Statements 1 & 3 are correct.
c. Statements 1, 2 & 3 are correct.
d. Statement 4 is correct.
d. Statement 4 is correct.
201
The cytochrome oxidase complex comprises the following:
1. Heme a3
2. Ferric
3. Ferrous
4. Copper
a. Statements 2 & 4 are correct.
b. All are correct.
c. Statements 1, 2 & 3 are correct.
d. Statements 1 & 3 are correct.
b. All are correct.
202
Energy that is generated from metabolic fuels during respiration but is not captured
in the ATP formation is released as?
a. CMP
b. Carbon dioxide
c. Oxygen
d. Heat
d. Heat
203
This enzyme is active in tissues that are involved in eicosanoid metabolism.
a. Peroxidase
b. Catalase
c. Oxidase
d. Reductase
a. Peroxidase
204
TRUE about ketone bodies.
A. used as fuel by the extra-hepatic tissues particularly
acetone
B. overproduction causes ketosis
C. produced by the kidneys
D. oxidation of fatty acids to acyl-CoA
B. overproduction causes ketosis
205
Which of the following has the INCORRECT match?
A. lipolysis – adipose tissue
B. fatty acid oxidation – mitochondria
C. ketogenesis – peroxisomes
D. fatty acid synthesis – cytosol
C. ketogenesis – peroxisomes
206
The toxin hypoglycin inactivates this particular enzyme
inhibiting ß-oxidation causing Jamaican vomiting sickness.
A. Acetyl-CoA carboxylase
B. Acyl-CoA synthetase
C. 3-hydroxybutyrate dehydrogenase
D. Acyl-CoA dehydrogenase
D. Acyl-CoA dehydrogenase
207
The free fatty acids are transported by blood associated with
___ .
A. a fatty acid-binding protein
B. oxygen
C. albumin
D. ß-lipoprotein
C. albumin
208
Which of the following is a saturated fatty acid?
A. Docosahexanoic acid
B. Oleic acid
C. Palmitic acid
D. Linoleic acid
C. Palmitic acid
209
The long-chain fatty acids get transported through the inner
mitochondrial membrane ___ .
A. as carnitine derivative.
B. requiring sodium-dependent carrier.
C. freely.
D. as acyl-CoA derivative.
A. as carnitine derivative.
210
Long-chain fatty acids get activated first in this cell
compartment.
A. mitochondria
B. microsomes
C. nucleus
D. cytosol
D. cytosol
211
The rate-limiting step in the synthesis of fatty acids is the conversion of acetyl-CoA to malonyl-CoA catalyzed by this enzyme.
A. Malonyl-CoA synthase
B. Malonyl-CoA carboxylase
C. Acetyl-CoA carboxylase
D. Acetyl-CoA decarboxylase
D. Acetyl-CoA decarboxylase
212
What form of energy is required for fatty acid synthesis?
A. FADH2
B. NADPH
C. ATP
D. NADH
C. ATP
213
Fatty acid elongation occurs in the endoplasmic reticulum
using ____ as the acetyl donor.
A. palmitate
B. acetate
C. malonyl-CoA
D. NADPH
C. malonyl-CoA
214
Which of the following BEST DESCRIBES the regulation of
acetyl-CoA carboxylase?
A. Activated by phosphorylation of the enzyme.
B. Hormones such as glucagon, epinephrine & insulin
regulates the enzyme.
C. Tricarboxylate transporter is located in the cytosol.
D. Citrate is transported from cytosol to mitochondria by the
tricarboxylate transporter
D. Citrate is transported from cytosol to mitochondria by the
tricarboxylate transporter
215
Removal of CO2 in fatty acid synthesis occurs in which step?
A. translation
B. activation
C. reduction
D. condensation
D. condensation
216
Which of these is not generated by the cyclooxygenase
pathway?
A. prostacyclins
B. prostaglandins
C. thromboxanes
D. leukotrienes
D. leukotrienes
217
The cyclooxygenase enzyme that increases during inflammation.
A. COX2
B. COX3
C. COX4
D. COX1
A. COX2
218
The enzyme which catalyzes the conversion of cyclic
endoperoxidase into PGE2.
A. dehydrogenase
B. cyclooxygenase
C. isomerase
D. thiokinase
B. cyclooxygenase
219
What is a characteristic of sphingolipids?
A. They all contain ceramide joined to a polar group.
B. They all contain a long-chain alcohol joined to isoprene.
C. They all contain a fatty acid joined to glycerol.
D. They all contain a carbohydrate joined to a phosphate group.
A. They all contain ceramide joined to a polar group
220
Plasmalogens and PAF are phosphoglycerols with an ether link
derived from:
A. phosphatidate
B. dihydroxyacetone phosphate
C. glycerol-3-phosphate
D. cardiolipin
B. dihydroxyacetone phosphate
221
This phospholipase is one of the major toxins secreted by
bacteria.
A. phospholipase C
B. phospholipase B
C. phospholipase D
D. phospholipase A1
A. phospholipase C
222
A genetic disorder caused by the accumulation of
sphingomyelin in the brain is called:
A. Fabry Disease
B. Tay-Sachs Disease
C. Niemann-Pick Disease
D. Gaucher’s Disease
C. Niemann-Pick Disease
223
Plasma lipids are mostly composed of ____ .
A. phospholipids
B. cholesterol
C. cholesteryl esters
D. triacylglycerols
D. triacylglycerols
224
The class of lipoproteins that is protective against
atherosclerosis.
A. low-density lipoproteins
B. chylomicrons
C. high-density lipoproteins
D. very low-density lipoproteins
C. high-density lipoproteins
225
Apolipoprotein E is found in the lipoproteins listed below, except:
A. VLDL
B. LDL
C. chylomicron remnants
D. chylomicrons
B. LDL
226
The lipoprotein lipase is present in the endothelial surfaces of adipose tissues, heart and it is required for hydrolysis and release of triglycerides from chylomicrons. Which of the apolipoprotein present in chylomicron serves as the activator of this enzyme?
A. Apo CII
B. Apo E
C. Apo B100
D. Apo B48
A. Apo CII
227
The HDL is taken up by the hepatocytes via _____.
A. LDL receptor
B. ATP-binding cassette transporters A1
C. Scavenger receptor BI
D. Apo CII receptor
C. Scavenger receptor BI
228
Hormone-sensitive lipase is activated by _____.
A. epinephrine
B. insulin
C. prostaglandin E
D. nicotinic acid
A. epinephrine
229
Mr. A has uncontrolled Type I Diabetes Mellitus who underwent
blood works. Abnormal results showed hyperglycemia
(644mg/dl) and hypertriglyceridemia (512mg/dl). The hypertriglyceridemia in this patient is most likely due to __ .
A. decreased lipoprotein lipase activity
B. deficiency of Apo CII
C. absence of hormone-sensitive lipas
D. increased hepatic triglyceride synthesis
A. decreased lipoprotein lipase activity
230
The correct order of lipoproteins in terms of density from highest to lowest?
A. HDL – LDL – IDL – VLDL – Chylomicrons
B. IDL – LDL – HDL – Chylomicrons – VLDL
C. VLDL – IDL – Chylomicrons – HDL -- LDL
D. Chylomicrons – IDL – LDL – HDL – VLDL
A. HDL – LDL – IDL – VLDL – Chylomicrons
231
A chronic alcoholic beverage drinker is at risk of developing
alcohol fatty liver disease. The accumulation of fats in the liver of
these individuals is due to the following, EXCEPT:
A. decreased metabolic clearance of ethanol
B. impaired fatty oxidation
C. excess production of NADH
D. Increased lipogenesis
A. decreased metabolic clearance of ethanol
232
Which of the following is NOT true?
A. Water soluble vitamins are not included in chylomicrons.
B. Apolipoprotein is a constituent of chylomicrons.
C. Active form of fatty acid is acyl-CoA.
D. Lipids are transported as chyme.
D. Lipids are transported as chyme.
233
What products are obtained from the hydrolysis of cholesterol
ester?
A. cholesterol and fatty acids
B. cholesterol and phospholipids
C. cholesterol and ester
D. cholesterol and proteins
A. cholesterol and fatty acids
234
Cholesterol serves as the precursor for the following biosynthetic
pathways, EXCEPT:
A. steroid hormone synthesis
B. thyroid hormone synthesis
C. aldosterone synthesis
D. bile acid synthesis
B. thyroid hormone synthesis
235
The regulatory enzyme involved in the pathway of cholesterol
synthesis.
A. Squalene epoxidase
B. HMG-CoA synthase
C. Thiolase
D. HMG-CoA reductase
D. HMG-CoA reductase
236
How many IPP molecules are required for the formation of
squalene?
A. 4
B. 5
C. 6
D. 7
A. 4
237
Which form of energy is required in the rate-limited step of
cholesterol synthesis?
A. AMP
B. FAD
C. ATP
D. NADH
D. NADH
238
Which of the following LEAST DESCRIBES cholesterol synthesis?
A. in stage 5, cholesterol is formed from lanosterol
B. starvation inhibits synthesis of cholesterol
C. T4 increases cholesterol synthesis
D. cholesterol is amphipathic in nature
C. T4 increases cholesterol synthesis
239
Which of the following enzymes is the rate-limiting enzyme of
bile acid synthesis?
A. 5-beta isomerase
B. 12-beta-hydroxylase
C. 7-alpha-hydroxylase
D. 12-alpha-hydroxylase
C. 7-alpha-hydroxylase
240
In a few instances, adrenal steroids are
synthesized from the following precursors
1. Progesterone
2. Squalene
3. Estradiol
4. Mevalonate
A. Statement 4 is correct
B. ALL statements are correct
C. Statements 2 and 4 are correct
D. Statements 1 and 3 are correct
E. Statements 1,2, and 3 are correct
C. Statements 2 and 4 are correct
The adrenal steroid hormones are synthesized from cholesterol, which is mostly
derived from the plasma, but a small portion is synthesized in situ from acetyl-CoA via
mevalonate and squalene.
241
The vitamin that is needed for for the
decarboxylation reaction in the formation of
dopamine
A. Vitamin b6
B. Vitamin b5
C. Vitamin b1
D. Vitamin b2
A. Vitamin b6
242
Regulation mechanism of phosphoprotein
phosphatase is best exemplified in which of the
following scenarios
A. Glucose metabolism
B. Glycogen metabolism
C. Protein metabolism
D. Lipid metabolism
B. Glycogen metabolism
243
Alternative substrate used for
the synthesis of triacylglycerol
EXCEPT
a. Lactate
b. Acetate
c. Glucose
d. Amino acids
b. Acetate
244
A direct precursor of
ketogenesis
a. Triacyglycerol
b. Acetyl-CoA
c. Lactate
d. Pyruvate
b. Acetyl-CoA
Acetyl-CoA can be converted
into the ketone bodies by
ketogenesis especially within the
cells of the liver and the
extrahepatic tissues.
245
In Glycolysis, which enzyme
us inhibited by Flouride?
a. Hexokinase
b. Aldolase
c. Glucokinase
d. Enolase
d. Enolase
Substances that inhibit enzymes
in glycolysis:
Iodoacetate - glycerol-3-
phosphate dehydrogenase
Fluoride - enolase
246
In Glycolysis, how many
ATPs are formed in one
molecule of glucose
a. 2ATPs
b. 4 ATPs
c. 6 ATPs
d. 8 ATPs
b. 4 ATPs
One molecule of glucose
produces 4 ATPs since fructose-
1,6- biphosphate is cleaved into
two molecules which will
eventually undergo series of
reactions both forming 2 moles
of pyruvate. However, since 2
ATPs were spent on hexokinase
and phosphofructokinase earlier
on the pathway of glycolysis,
only a net amount of 2 ATPs are
produced.
247
In most tissues, which
hormone controls the entry of
glucose into the cell?
a. Glucagon
b. Somatostatin
c. Adrenalin
d. Insulin
d. Insulin
Insulin, produced by the
pancreas regulates the glucose
levels in the blood by increasing
glucose entry into the cells for
ATP production
248
Oxidation of Pyruvate occurs
in which part of the cell
a. Cytosol
b. Nucleus
c. Mitochondria
d. Golgi Apparatus
c. Mitochondria
Pyruvate is oxidized in the
mitochondria after it is shuttled
into the mitochondria by a
proton symporter, for ATP
production, or converted into
ketones, as it enters the Cori
cycle.
249
Which compound inhibits the
action of pyruvate
dehydrogenases in the oxidation
of pyruvate
a. Arsenic
b. Iodoacetate
c. NADH
d. Coenzyme A
a. Arsenic
Arsenic inhibits the pyruvate
dehydrogenase enzyme
complex.
250
Site for glycolysis in the cell
a. Cytosol
b. Nucleus
c. Mitochondria
d. Golgi apparatus
a. Cytosol
Glycolysis - cytosol
Kreb’s Cycle - mitochondria
Oxidation of pyruvate -
MItochondria
251
Which statement concerning
the glycolytic and gluconeogenic
pathways is correct?
a. Gluconeogenesis Is
catabolic and glycolysis
is anabolic
b. Both are anabolic
c. Gluconeogenesis is
anabolic and glycolysis
is catabolic
d. Both are catabolic
c. Gluconeogenesis is anabolic and glycolysis
is catabolic
Anabolic pathways are involved in the synthesis of larger and more complex compounds from smaller precursors—for example, the
synthesis of protein from amino acids and the synthesis of reserves of triacylglycerol and glycogen. Anabolic pathways are endothermic.
(2)Catabolic pathways are involved
in the breakdown of larger molecules,commonly involving oxidative reactions; they are exothermic, producing reducing equivalents, and, mainly via the
respiratory chain (see Chapter13),
ATP.
252
What body conditions favor
gluconeogenesis over glycolysis
a. High blood sugar
b. Starvation
c. Increasing cellular levels
of AMP
d. low cellular levels of
pyruvate
b. Starvation
Liver and kidney are the major
gluconeogenic tissues; the kidney
may contribute up to 40% of total
glucose synthesis in the fasting state
and more instarvation. After an
overnight fast, glycogenolysis and
gluconeogenesis make
approximately equal contributions to
blood glucose; as glycogen reserves
are depleted, so gluconeogenesis
becomes progressively more
important.
253
Which glycolytic reaction
cannot be directly reversed in
gluconeogenesis
a. 1,3-biphosphoglycerate -
> 3-phosphoglycerate
b. Glucose-6-phosphate-
>fructose-6-phosphate
c. Glyceraldehyde 3-
phosphate->1,3-
biphosphoglycerate
d. Glucose->glucose-6-
phosphate
d. Glucose->glucose-6-
phosphate
Glucose enters glycolysis by
phosphorylation to glucose-6-
phosphate, catalyzed by hexokinase,
using ATP as the phosphate donor.
Under physiological conditions, the
phosphorylation of glucose to
glucose-6-phosphate can be
regarded as irreversible. Hexokinase
is inhibited allosterically by its
product, glucose-6-phosphate.
254
Which enzyme is down
regulated in CHO feeding?
a. Pyruvate Kinase
b. Pyruvate dehydrogenase
c. Pyruvate carboxylase
d. Hexokinase
c. Pyruvate carboxylase
255
How many endothermic
reactions are involved in the reversal of the reaction catalyzed
by pyruvate kinase?
a. 2
b. 4
c. 3
d. 1
a. 2
Reversal of the reaction catalyzed
by pyruvate kinase in glycolysis involves two endothermic reactions.
Mitochondrial pyruvate carboxylase
catalyzes the carboxylation of
pyruvate to oxaloacetate, an ATP-
requiring reaction in which the
vitamin biotin is the coenzyme.
Biotin binds CO2 from bicarbonate
as carboxybiotin prior to the
addition of the CO2 to pyruvate (see
Figure 44–14). The resultant
oxaloacetate is reduced to malate,
exported from the mitochondrion
into the cytosol and there oxidized
back to oxaloacetate. A second
enzyme, phosphoenolpyruvate
carboxykinase, catalyzes the
decarboxylation and
phosphorylation of oxaloacetate to
phosphoenolpyruvate using GTP as
the phosphate donor.
256
What glycogen storage
disease exhibits deficiency in
liver phosphorylase?
a. Tarui dss ppl
b. Hers dss
c. Pompe dss
d. McArdie dss
b. Hers dss
257
Which subunit of muscle
phosphorylase Kinase is
identical to calmodulin?
a. α-subunit
b. β-subunit
c. γ-subunit
d. δ-subunit
d. δ-subunit
Glycogenolysis in muscle increases
several 100-fold at the onset of
contraction; the same signal
(increased cytosolic Ca2+ ion
concentration)is responsible for
initiation of both contraction and
glycogenolysis. Muscle
Phosphorylase kinase, which
activates glycogen phosphorylase, is
a tetramer of four different subunits,
α, β, γ, and δ. The α and β subunits
contain serine residues that are phosphorylated by cAMP-dependent
protein kinase. The δ subunit is
identical to the Ca2+-binding
protein calmodulin and binds four
Ca2+. The binding of Ca2+activates
the catalytic site of the γ subunit
even while the enzyme is in
thedephosphorylated b state; the
phosphorylated a form is only fully
activated in the presence of high
concentrations of Ca2+.
258
Another name for the Cori
cycle
a. TCA
b. Pentose phosphate cycle
c. Lactic Acid cycle
d. Glucose-alanine cycle
c. Lactic Acid cycle
Glucose is formed from two groups
of compounds that undergo
gluconeogenesis: (1) those that
involve a direct net conversion to
glucose, including most amino acids
and propionate and (2) those that are
the products of the metabolism of
glucose in tissues. Thus, lactate,
formed by glycolysis in skeletal
muscle and erythrocytes, is
transported to the liver and kidney
where it reforms glucose, which
again becomes available via the
circulation for oxidation in the
tissues. This process is known as the
Cori cycle, or the lactic acid cycle
259
Which of the following is
increased by glucagon?
a. Fatty acid synthesis
b. Protein synthesis
c. Glycogen synthesis
d. Ketogenesis
d. Ketogenesis
260
What is the renal threshold
of glucose
a. 5 mmol/L
b. 2mmol/L
c. 10 mmol/L
d. 20 mmol/L
c. 10 mmol/L
When the blood glucose
concentration rises above about 10
mmol/L, the kidney also exerts a
(passive) regulatory effect. Glucose
is continuously filtered by the
glomeruli, but is normally
completely reabsorbed in the renal
tubules by active transport. The
capacity of the tubular system to
reabsorb glucose is limited to a rate of about 2 mmol/min, and in
hyperglycemia (as occurs in poorly
controlled diabetes mellitus), the
glomerular filtrate may contain more
glucose than can be
reabsorbed,resulting in glucosuria
when the renal threshold for glucose
is exceeded.
261
ACETYL-COA integrates
glucose and fatty acids
The citric acid cycle is the final
common pathway for the
oxidation of CHO, lipid and
CHON because glucose, fatty
acids and most amino acids are
metabolized to acetyl CoA
262
Carbon monoxide blocks
complex IV
Classic poisons H2S, Carbon
monoxide and cyanide inhibit
complex IV and can therefore
totally arrest respiration.
263
MALONATE inhibits
succinate dehydrogenase
Malonate is a competitive
inhibitor of the enzyme
succinate dehydrogenase.
264
OXALOACETATE is
needed for continuous citric acid
The citric acid cycle is the final
pathway for the oxidation of
carbohydrate, lipid and protein.
Their common end-metabolite,
acetyl CoA reacts with oxaloacetate to form citrate
265
ACYL-COA is not found in
the mitochondrial matrix
Enzymes of inner membrane:
Electron carriers (complex I- IV)
ATP synthase
Membrane transporters
Enzymes of mitochondrial
matrix:
Citric acid cycle enzymes
Beta oxidation enzymes
Pyruvate dehydrogenase
Enzymes of outer membrane:
Acyl CoA synthetase
Glycerolphosphate acyl
transferase
266
PROTONS leads to
uncoupling
Uncouplers dissociate
oxidation in the respiratory
chain from phosphorylation.
Uncouplers are amphipathic
and increase the permeability
of the lipoid inner
mitochondrial membrane to
protons thus reducing
electrochemical potential and
short circuiting the ATP
synthase. In this way,
oxidation can proceed
without phosphorylation.
267
STATE 4 resting state
States of respiratory control
State 1 – availability of ADP
and substrate
State 2 – Availability of
substrate only
State 3 – The capacity of the
respiratory chain itself, when all
substrates and components are
present in saturating amounts
State 4 – availability of ADP
only, most cells are in resting
state
State 5 – availability of oxygen
only
268
ASPARTATE transamination
leads to formation of
oxaloacetate
Aminotransferase (transaminase)
reactions form pyruvate from
alanine, oxaloacetate from
aspartate and alpha-ketoglutarate
from glutamate
269
Complex 3 is Q-
CYTOCHROME C
OXIDOREDUCTASE
Components of the respiratory
chain are contained in 4 large
complexes embedded in the
inner mitochondrial membrane.
Complex I - NADH-Q
oxidoreductase
Complex II – Succinate-Q
reductase
Complex III – Q-cytochrome c
oxidoreductase
Complex IV – Cytochrome c
oxidase
270
The following follows the
rules of thermodynamics
A. Entropy is the extent of
disorder of randomness of the system and becomes
maximum as equilibrium
B. Change in enthalpy =
change in energy sa internal
reaction
C. Energy may be transferred
from one part of the system
to another, or may be
transformed into another
form of energy.
D. All of the Above
D. All of the Above
during any change;
2. The total entropy of a system
must increase if a process is to
occur spontaneously;
3. The entropy of a system
approaches a constant value as
the temperature approaches zero
4. The Zeroth Law states that if
two bodies are in thermal
equilibrium with some third
body, then they are also in
equilibrium with each other.
This establishes temperature as a
fundamental and measurable
property of matter.
271
Endergonic reactions are
coupled with exergonic reactions
summed up in which body
process?
A. Anabolism
B. Catabolism
C. Metabolism
D. Heterotropism
C. Metabolism
The exergonic reactions are
termed catabolism, whereas the
synthetic reactions that build up
substance are termed anabolism.
The combined catabolic and
anabolic processes constitute
metabolism.
272
Nutrient component factor in
high energy compound such as
ATP (?)
A. Fe
B. Cu
C. Mg
D. P
C. Mg
ATP plays a central role in the
transference of free energy from
the exergonic to the endergonic
processes. ATP is a nucleotide
consisting of the nucleoside
adenosine, and three phosphate
groups. In its reactions in the
cell, it functions as the Mg2+
complex
273
Phosphate donors in the
formation of ATP, except:
A. Phosphoenolpyruvate
B. Glucose-6-phosphate
C. 1,3-bisphosphoglycerate
D. Succinyl- CoA
B. Glucose-6-phosphate
274
All of the ff catalytic enzyme
produces 1-phosphate in the
citric acid cycle?
A. Phosphoglycerate kinase
B. Pyruvate kinase
C. Succinate thiokinase
D. Adenylyl kinase
C. Succinate thiokinase
Succinyl-CoA is converted to
succinate thiokinase (succinyl-
CoA synthase). This is the only
example of substrate level
phosphorylation in the citric acid
cycle.
275
The reaction is inhibited by
carbon monoxide because it
blocks this enzyme
A. Xanthine oxidase
B. Amino acid oxidase
C. Cytochrome c Oxidase
C. Cytochrome c Oxidase
A number of drugs (eg,
amobarbital) and poisons (eg,
cyanide, carbon monoxide)
inhibit Cytochrome c Oxidase
(Complex IV) which arrests
respiration.
276
Fast acting 4-heme containing
enzyme found in blood and
mucous membrane
A. Peroxidase
B. Catalase
C. Oxidase
D. Superoxide dismutase
B. Catalase
Catalase is a hemoprotein
containing four heme groups. It
can act as a peroxidase, and is
also able to catalyze the
breakdown of H2O2 formed by
the action of oxygenases to
water and oxygen
277
Which specific compound is
employed in removing 2
hydrogen bonds in a fatty acid to
form a carbon-carbon double
bond (the process is termed
desaturation) for a fatty acid
metabolism?
A. Cytochrome b5
B. Cytochrome c
C. Class 1 P450
D. Class 2 P450
A. Cytochrome b5
Cytochrome b5 has an important
role as a fatty acid desaturase.
Together with cytochrome P450
in the endoplasmic reticulum of
the liver, it is responsible for
about 75% of the modification
and degradation of drugs which
occur in the body.
278
The redox potential of
NAD/NADH = -0.32 and
O2/water = +0.82 implies that:
A. NAD/NADH has a tendency
to gain electrons while
O2/Water has a tendency to lose
electrons
B. NAD/NADH has a tendency
to lose electrons while
O2/Water has a tendency to
gain electrons
C. NAD/NADH has a tendency
to gain more electrons and faster
than O2/water
D. NAD/NADH has a tendency
to lose more electrons and faster
than O2/water
NAD-linked dehydrogenases
catalyze oxidoreduction
reactions. When a substrate is
oxidized, it loses 2 hydrogen
atoms and 2 electrons. One H+
and both electrons are accepted
by NAD+ to form NADH and
the other H+ is released.
279
Flavin-dependent
dehydrogenases except
A. Succinate dehydrogenase
B. Fatty Acyl-CoA
dehydrogenase
C. Glycerol-3-phosphate
dehydrogenase
D. Glucose-6-phosphate
dehydrogenase
C. Glycerol-3-phosphate
dehydrogenase
Glycerol-3-phosphate
dehydrogenase is not a flavin-
dependent dehydrogenase; it is
however important in lipid
metabolism.
280
Mechanism for lowering
serum uric acid levels is the
target for inhibition of this
enzyme
A. Amino acid oxidase
B. Xanthine oxidase
C. 3 hydroxyanthaniline
dioxygenase
D. Superoxide dismutase
B. Xanthine oxidase
Xanthine oxidase containing
molybdenum plays an important
role in the conversion of purine
bases to uric acid.
281
Most important role of
dehydrogenase in anaerobic
metabolism
A. Transfer Hydrogen to another
substrate
B. Transfer of electrons to
respiratory chain
Lactate dehydrogenase catalyzes
reduction of pyruvate to lactate,
permitting the oxidation of
NADH, which permits another
molecule of glucose to undergo
glycolysis.
282
Case study. Amylopectin branching something.
Answer is branching enzyme
Note: Amylopectin (80-87%), which consists of branched chains, consists of 24 to 30 glucose residues with
α1 → 4 linkages in the chains and by α1 → 6 linkages at the branch points
283
Case. Type 2 Diabetes, which will less likely to occur in Type 2 than Type 1:
A. Retinopathy
B. Weight gain
C. Cardiovascular Disease
D. Hypoglycemic coma
E. Neuropathy
D. Hypoglycemic coma
Note: Patients with Type 1 DM always use insulin and have a wider range in blood glucose levels than
patients with Type 2 DM. Patients with Type 2 DM are more likely to experience hypoglycemic coma due
to diabetic hyperosmolar syndrome than from diabetic ketoacidosis or hypoglycemia.
284
Glycolysis equation from glucose to lactate
Answer: Glucose + 2 ADP + 2 Pi 2 lactate + 2 ATP + 2 H2O
285
In glycolysis, the ff will occur in the absence of oxygen, EXCEPT:
A. Impaired mitochondrial reoxidation of NADH
B. Limit ATP binding with available molecule of oxidized glucose
C. NADH is reoxidized by converting lactate to pyruvate, allowing glycolysis
D. Lactate accumulation
E. NOTA
C. NADH is reoxidized by converting lactate to pyruvate, allowing glycolysis
NOTE: When oxygen is in short supply, mitochondrial reoxidation of NADH formed during glycolysis is
impaired, and NADH is reoxidized by reducing pyruvate to lactate, so permit- ting glycolysis to continue.
While glycolysis can occur under anaerobic conditions, this has a price, for it limits the amount of ATP
formed per mole of glucose oxidized, so that much more glucose must be metabolized under anaerobic than
aerobic conditions. In yeast and some other microorganisms, pyruvate formed in anaerobic glycolysis is
not reduced to lac- tate, but is decarboxylated and reduced to ethanol.
286
In glycolysis, the ff will occur in the absence of oxygen, EXCEPT:
A. Impaired mitochondrial reoxidation of NADH
B. Limit ATP binding with available molecule of oxidized glucose
C. NADH is reoxidized by converting lactate to pyruvate, allowing glycolysis
D. Lactate accumulation
E. NOTA
C. NADH is reoxidized by converting lactate to pyruvate, allowing glycolysis
NOTE: When oxygen is in short supply, mitochondrial reoxidation of NADH formed during glycolysis is
impaired, and NADH is reoxidized by reducing pyruvate to lactate, so permit- ting glycolysis to continue.
While glycolysis can occur under anaerobic conditions, this has a price, for it limits the amount of ATP
formed per mole of glucose oxidized, so that much more glucose must be metabolized under anaerobic than
aerobic conditions. In yeast and some other microorganisms, pyruvate formed in anaerobic glycolysis is
not reduced to lac- tate, but is decarboxylated and reduced to ethanol.
287
Glucose-6-phosphate is a component of this metabolic pathway except
A. Glycolysis
B. Gluconeogenesis
D. Citric acid cycle
E. Glycogenesis
D. Citric acid cycle
288
E. Glycogenin
NOTE: The initial steps in glycogen synthesis involve the protein glycogenin, a 37-kDa protein that is
glucosylated on a spe- cific tyrosine residue by UDPGlc. Glycogenin catalyzes the transfer of a further
seven glucose residues from UDPGlc, in 1 → 4 linkage, to form a glycogen primer, substrate for glycogen synthase
289
In glycogen synthesis, what enzyme transfers a part of 1-4 chain to a neighboring chain to form a
1-6 linkage?
A. Glycogen synthase
B. Branching enzyme
C. Glucogenin
D. Debranching enzyme
E. Glycogen phosphorylase
B. Branching enzyme
NOTE: When a growing chain is at least 11 glucose residues long, branching enzyme transfers a part of
the 1 → 4 chain (at least six glucose residues) to a neighboring chain to form a 1 → 6 linkage, establishing a branch point.
290
Glycogen Storage Disease deficiency in Branching enzyme
A. Pompe ds
B. Tarui ds
C. Hers ds
D. Andersen ds
E. Cori ds
D. Andersen ds
291
Glycogen storage disease, liver phosphorylase
A. Pompe
B. Taraui
C. Hers
D. Andersen
E. Cori
C. Hers
292
Glycogen storage disease deficient in cAMP-dependent protein kinase
A. Type 0
B. Type IX
C. Type X
D. Type VIII
E. Type Ib
C. Type X
Mnemonics: Viagra Pill Cause A Matigas Hard Tite
293
Rate limiting enzyme for glycogenolysis
A. Glycogen synthase
B. Debranching enzyme
C. Branching enzyme
D. Glycogen phosphorylase
E. Glycogen phosphatase
D. Glycogen phosphorylase
NOTE: Glycogen phosphorylase catalyzes the rate-limiting step in glycogenolysis—the phosphorolytic
cleavage of the 1 → 4 link- ages of glycogen to yield glucose-1-phosphate. Glycogen phosphorylase requires pyridoxal phosphate as its coenzyme.
294
Anaerobic glycolysis refers to generation of ATP:
A. Without involvement of ADP
B. Without use of glycogen
C. Without use of oxygen
D. Without pyruvate
E. Conversion of pyruvate to lactate
C. Without use of oxygen
295
First law of thermodynamics
A. entopry reaches 0-constant (3rd law)
B. energy can neither be created nor destroyed
C. the total entropy of a system must increase if a process is to occur spontaneously (2nd law)
D. NOTA
B. energy can neither be created nor destroyed
The first law of thermodynamics states that the total energy of a system, including its surroundings, remains constant. It implies that within the total system, energy is neither lost nor gained during any change.
296
Pathway that yield the most number of high energy phosphates
A. Glycolysis
B. Citric acid cycle
C. PPP
D. Oxidative phosphorylation
D. Oxidative phosphorylation
There are three major sources of ~P taking part in energy conservation or energy capture:
1. Oxidative phosphorylation is the greatest quantitative source of ~P in aerobic organisms. ATP is
generated in the mitochondrial matrix as O2 is reduced to H2O by electrons passing down the
respiratory chain.
2. Glycolysis. A net formation of two ~P results from the formation of lactate from one molecule of
glucose, generated in two reactions catalyzed by phosphoglycerate kinase and pyruvate kinase,
respectively.
3. The citric acid cycle. One ~P is generated directly in the cycle at the succinate thiokinase step.
It can be estimated that nearly 90% of the high-energy phosphates produced from the complete oxidation
of 1 mole glucose is obtained via oxidative phosphorylation coupled to the respiratory chain.
297
Dehydrogenase that acts as a carrier of electrons
A. NADH dehydrogenase
B. Dihydrolipoyl dehydrogenase
C. Aldehyde dehydrogenase
D. Succinate dehydrogenase
A. NADH dehydrogenase
NADH dehydrogenase acts as a carrier of electrons between NADH and the components of higher redox
potential.
Other dehydrogenases such as succinate dehydrogenase, acyl-CoA dehydrogenase, and mitochondrial
glycerol-3-phosphate dehydrogenase transfer reducing equivalents directly from the substrate to the
respiratory chain.
Another role of the flavin-dependent dehydrogenases is in the dehydrogenation (by dihydrolipoyl
dehydrogenase) of reduced lipoate, an intermediate in the oxidative decarboxylation of pyruvate and α- ketoglutarate.
298
Enzyme that converts purine bases to uric acid
A. Xanthine Oxidase
B. L-amino acid oxidase
C. Aldehyde dehydrogenase
D. Cytochrome oxidase
A. Xanthine Oxidase
Xanthine oxidase, which contains molybdenum and plays an important role in the conversion of purine
bases to uric acid, and is of particular significance in uricotelic animals.
L-amino acid oxidase, an enzyme found in kidney with general specificity for the oxidative deamination
of the naturally occurring l-amino acids
Aldehyde dehydrogenase, an FAD-linked enzyme present in mammalian livers, which contains
molybdenum and nonheme iron and acts on aldehydes and N-heterocyclic substrates.
Cytochrome oxidase is a hemoprotein widely distributed in many tissues, having the typical heme
prosthetic group present in myoglobin, hemoglobin, and other cytochromes
299
For metabolic processes to be efficient, this enzyme is central to energy homeostasis:
A. Pyrophosphate
B. Phosphorylase
C. Diphosphate
D. Adenylyl kinase
D. Adenylyl kinase
Adenylyl kinase is important for the maintenance of energy homeostasis in cells because it allows:
1. The group transfer potential in ADP to be used in the synthesis of ATP.
2. The AMP formed as a consequence of activating reactions involving ATP to rephosphorylated to
ADP.
3. AMP to increase in concentration when ATP becomes depleted so that it is able to act as a metabolic (allosteric) signal to increase the rate of catabolic reactions, which in turn lead to the generation of more ATP
300
High energy intermediate or carrier molecule of most cells
A. ATP
B. ADP
C. GDP
D. AMP
A. ATP
In the living cell, the principal high-energy intermediate or carrier compound is ATP
301
Chemiosmotic Theory
High phosphate production is due to conformational change in ATP synthase caused by movement of proton through the gradient
302
Utilizes carnitine system for transport to mitochondria
A. 3-hydroxybutyric acid
B. Long chain fatty acids
C. Tricarboxylates
D. Acetic acid
B. Long chain fatty acids
303
Main pathway for production of ATP in oxidation of metabolic fuels
A. Glycolysis
B. Oxidative phosphorylation
C. Citric acid cycle
D. Electron transport chain
B. Oxidative phosphorylation
304
TCA intermediate that is in free solution in cytosol for fatty acid synthesis when its enzyme is
inhibited
A. Malate
B. Fumarate
C. Citrate
D. a-ketoglutarate
C. Citrate
This provides integration of citric acid cycle activity with the provision of citrate in the cytosol as a source
of acetyl-CoA for fatty acid synthesis. Citrate is only available in free solution to be transported from the
mitochondria to the cytosol for fatty acid synthesis when aconitase is inhibited by accumulation of its product, isocitrate.
305
Enzyme catalyzing production of first NADH in citric acid cycle
A. Pyruvate dehydrogenase
B. Isocitrate dehydrogenase
C. Succinate dehydrogenase
D. a-ketoglutarate dehydrogenase
B. Isocitrate dehydrogenase
306
Substrate level phosphorylation in citric acid cycle
A. Oxalosuccinate to a-ketoglutarate
B. a-ketoglurate to succinyl CoA
C. Succinate to fumarate
D. Succinyl CoA to succinate
D. Succinyl CoA to succinate
307
Form of metabolic fuel that enters TCA
A. Oxaloacetate
B. Acetyl CoA
C. Glucose
D. Pyruvate
B. Acetyl CoA
308
Energy from metabolic fuels during respiration that is not captured in ATP formation is released
as:
A. Heat
B. Oxygen
C. Carbon dioxide
D. CMP
A. Heat
The remaining free energy that is not captured as high-energy phosphate is liberated as heat. This need not
be considered “wasted” since it ensures that the respiratory system as a whole is sufficiently exergonic to
be removed from equilibrium, allowing continuous unidirectional flow and constant provision of ATP. It also contributes to maintenance of body temperature.
309
Morse Type.
A. 1 and 3 is true.
B. 2 and 4 is true.
C. 1, 2, and 3 is true.
D. Only 4 is true.
E. All the statements are true.
The enzyme cytochrome oxidase reacts with the following compounds and inhibiting its function.
ANS: C
1. Cyanide
2. Hydrogen sulfide
3. Carbon monoxide
4. Carboxin
310
Morse Type.
A. 1 and 3 is true.
B. 2 and 4 is true.
C. 1, 2, and 3 is true.
D. Only 4 is true.
E. All the statements are true.
It is true of cytochrome oxidase allowing it to carry its function. ANS: B
1. Ferrous
2. Heme a+a3
3. Ferric
4. Copper
311
Morse Type.
A. 1 and 3 is true.
B. 2 and 4 is true.
C. 1, 2, and 3 is true.
D. Only 4 is true.
E. All the statements are true.
This enzyme transfers reducing equivalents directly from substrate to the respiratory chain. ANS:
A
1. Acyl-coA dehydrogenase
2. NADH dehydrogenase
3. Glycerol-3-phosphate dehydrogenase
4. Dihydrolipoyl dehydrogenase
Other dehydrogenases such as succinate dehydrogenase, acyl-CoA dehydrogenase, and mitochondrial glycerol-3-phosphate dehydrogenase transfer reducing equivalents directly from the substrate to the
respiratory chain.
312
Morse Type.
A. 1 and 3 is true.
B. 2 and 4 is true.
C. 1, 2, and 3 is true.
D. Only 4 is true.
E. All the statements are true.
Reactions catalyzed by this/these enzyme(s) produce(s) hydrogen peroxide. ANS: D
1. Catalase
2. Dehydrogenase
3. Peroxidase
4. Oxidase
Oxidases catalyze the removal of hydrogen from a substrate using oxygen as a hydrogen acceptor. They form water or hydrogen peroxide as a reaction product.
Peroxidase and Catalase catalyze the breakdown of H2O2.
313
Morse Type.
A. 1 and 3 is true.
B. 2 and 4 is true.
C. 1, 2, and 3 is true.
D. Only 4 is true.
E. All the statements are true.
Primary reaction for "activation" reaction to proceed. Thus, converting a thermodynamically
unfavorable to favorable ones. ANS: A
1. Phosphorylation
2. Oxidation
3. Phosphate Hydrolysis
4. Reduction
ATP Allows the Coupling of Thermodynamically Unfavorable Reactions to Favorable Ones
314
MATCHING TYPE:
A. NUCLEUS
B. PEROXISOME
C. MITOCHONDRIA
D. ENDOPLASMIC RETICULUM
E. NOTA
90. Chitin ANS: E
91. Pectin ANS: E
92. Zellweger syndrome ANS: B
93. Catalase and oxidase ANS: B
94. HSP ANS: C
95. Translocon ANS: D
96. Ran ANS: A
97. Karyopherins ANS: A
98. Tom 20/22 ANS: C
99. Infantile refsum ANS: B
100. SRP receptor ANS: D
315
Which is an essential substrate for de novo purine synthesis?
Aspartate
Carbon dioxide
Glutamate
A & B
All of the above
Aspartate & Carbon dioxide
316
Activation of protein kinase C requires the following substances except:
A. Phospholipase C
B. Adenylyl Cyclase
C. Calcium
D. G Protein
B. Adenylyl Cyclase
317
Which among the following is considered a primary bile acid?
A. Lithocholic acid
B. Cholic acid
C. Deoxycholic acid
D. Ursodeoxycholic acid
B. Cholic acid
318
Component of phosphatidylinositol that activates protein kinase c
A. Phosphatidylinositol 4,5
B. IP3
C. Diacylglycerol
D. Calcium
C. Diacylglycerol
319
Mother of all steroid hormones
Cholesterol
Pregnenolone
Testosterone
Progesterone
Cholesterol
320
Which second messenger system is utilized by the hormone glucagon?
A. Tyrosine kinase
B. cGMP Guanylate kinase
C. None, it binds intracellularly
D. cAMP, Adenylyl cyclase
D. cAMP, Adenylyl cyclase
321
True of lipolysis in adipocytes.
- Something about stimulating glycerol kinase
- Triglyceride lipase activated by increase in cAMP
- Insulin induces increased cAMP
Triglyceride lipase activated by increase in cAMP
322
Committed step in biosynthesis of cholesterol
Conversion of Mevalonate from HMG CoA
323
Abetalipoproteinemia defect on what protein
Apo E
Apo B
VLDL
LDL Receptor
Apo B
324
The multi-enzyme complex for the de novo synthesis of fatty acids contain at least
One-SH group
Two- SH group
Three-SH group
Four-SH group
Two- SH group
325
Nascent HDL source of Apo C and E
IDL
VLDL
LDL
HDL from liver
HDL from liver
326
How many double bonds in Arachidonic acid?
1
2
3
4
4
327
Acetyl coa carboxylase requires this vitamin to function
pantothenic acid
Biotin
Pyridoxal phosphate
Biotin
328
This lipid functions as a secondary messenger in the regulation of pathways for cell differentiation and cell growth. It is very important in maintaining skin moisture and is often incorporated in skin care products.
Cardiolipin
Ceramide
Choline
Ceramide
329
Key intermediate compound in the formation of triacylglycerol and phospholipid
A.
B. Choline-CDP
C. Phosphatidylserine
D. Phosphatidate
D. Phosphatidate
330
Alanine is formed from pyruvate through this metabolic process
Oxidation
Amidation
Transamination
Hydroxylation
Transamination
331
Glucose alanine cycle provides
A. An indirect means of removing nitrogen and replenishing energy
B.
C. A cycle of direct synthesis of carbohydrates
D. Provides the enzymes for gluconeogenesis
A. An indirect means of removing nitrogen and replenishing energy
332
Which of the following is not a branched chain amino acid?
Leucine
Lysine
Isoleucine
Valine
Lysine
333
Which of the following amino acid is not required for creatine synthesis
A. Serine
B. Glycine
C. Arginine
D. Methionine
A. Serine
334
Common compound of TCA cycle and Urea cycle
Oxaloacetate
A-ketoglutarate
Succinyl-CoA
Fumarate
Fumarate
335
True of GDH
A. Release of nitrogen as ammonia using NADH
B. Conversion of alpha amino nitrogen to ammonia by GDH and glutamine is called transdeamination
C. Inhibited by ADP
D. Activated by ATP, GTP and NADH
B. Conversion of alpha amino nitrogen to ammonia by GDH and glutamine is called transdeamination
336
Cytosolic enzymes in urea cycle except
A. Argininosuccinate synthetase
B. Ornithine carbamoyltransferase
C. Argininosuccinate lyase
D. Arginase
B. Ornithine carbamoyltransferase
337
Visible fat is present in
1. Milk
2. Egg yolk
3. Pulses
4. Coconut oil
4. Coconut oil
338
Acetyl-CoA generated from the breakdown of pyruvate can be a substrate for the following:
1. Cholesterol
2. Fatty acid
3. Steroid hormones
4. Glucose
1,2,3
339
Substance/s lacking in adipose tissue
Hormone sensitive lipase
G3P dehydrogenase
cAMP-dependent protein kinase
Glycerol kinase
Write A if statements 1 and 3 are correct
Write B if statements 2 and 4 are correct
Write C if statements 1, 2, 3 are correct
Write D if statement 4 is correct
Write E if ALL statements are correct
B. 2 and 4
340
same with ketogenesis and cholesterol
a. acetyl coa carboxylase
b. thiolase
c. acyl synthetase
d. hmg coa synthase
B. Both 2 and 4
341
The following polyunsaturated fatty acids can be synthesized in the body in the presence of active precursors:
A. Palmitoleic acid
B. Arachidonic acid
C. Oleic acid
D. Eicosanpentoenoic acid
B. Arachidonic acid
342
78.Enzyme both present in ketogenesis and fatty acid synthesis
A.Acetyl Decarboxylase
B. Thiolase
C. Acetyl Synthase
D. HMG Synthase
B. Thiolase
343
Co enzymes in FA beta oxidation
NAD
FAD
344
Phosphatidate is the parent compound of which acylglycerol?
1. Cardiolipin
2. Plasmalogen
3. Triacylglycerol
4. Phosphocholine
1&3
345
A. 1&3 is correct
B. 2&4 is correct
C. Only 4 is correct
E. All is correct
81. Acetyl-coa carboxylase inhibited by:
1.Phosphorylation
2.Glucagon
3.Increased acyl coa
4.AMPK
E. All is correct
346
Importance of peroxisomes in lipid metabolism
1- fatty acid beta oxidation
2- branched chain alpha oxidation
3- Esther phospholipid synthesis
4. Isoprenoid biosynthesis
A. 1&3 is correct
B. 2&4 is correct
C. Only 4 is correct
E. All is correct
E. All is correct
347
Therapeutic use of prostanoids
1 - Blood Pressure
2 - Nasal congestion relief
3 - Sleep promotion
4 - Abortifacient
A. 1,3
B. 2,4
C. 1,2,3
D. 4 only
E. AOTA
E. AOTA
348
True of Ketone bodies
1. Elevated in uncontrolled diabetes mellitus
2. Produced after diet or starvation
3. Abnormal levels lead to acidosis
4. Utilized by the liver during prolonged starvation
A. 1,3
B. 2,4
C. 1,2,3
D. 4 only
E. AOTA
C. 1,2,3
349
Bronchoconstriction synthesis pathway is involved in
1. Thromboxane
2. Lipoxins
3. Prostacyclin
4. Leukotrienes
2&4
350
Stimulation of LCAT
A. IDL
B. LDL
C. VLDL
D. HDL
D. HDL
351
Which of the following conditions most likely contributes to elevated levels of liver enzymes (SGPT) in the blood?
1. Overactive B-oxidation (?)
2. Active lipogenesis
3. Bile
4. Overproduction of ketone bodies
2&4
352
Fabry disease (what are the symptoms and its deficiency)
a- Galactosidase
Skin rash, kidney failure (full symptoms only in males; X-linked recessive)
353
Familial hypercholesterolemia type 2
Defective LDL receptors of Apo B
Atherosclerosis and coronary heart disease
354
Tay Sachs symptom & Deficiency
Hexosaminidase A, S
Mental retardation, blindness, muscular weakness
355
Familial hyperlipoproteinemia type 3
Abnormality in Apo E
Atherosclerosis and Xanthoma
356
Adipose tissue as the site of something (lipid or FFA, sorry nakalimot) metabolism
A. TAG synthesis
B. TAG degradation
C. BOTH
D. NONE
B. TAG degradation
357
Stimulated by catecholamine release
TG degradation
358
Stimulation of ATP-citrate lyase
TG Synthesis
