3rd LE Flashcards
True of Myokinase:
1. Catalyzes the irreversible transfer of phosphate groups from ADP
to ATP. X
2. Promotes catabolic reactions in the presence of increased AMP
concentration.
3. The enzyme is present only in muscle cells. X
4. Allows AMP to be rephosphorylated to ADP.
A. Statements 2 & 4 are correct.
B. All statements are correct.
C. Statements 1 & 3 are correct.
D. Statements 1, 2 & 3 are correct.
A. Statements 2 & 4 are correct.
Myokinase:
2. Promotes catabolic reactions in the presence of increased AMP
concentration.
4. Allows AMP to be rephosphorylated to ADP.
Enumerate the 3 major sources of energy conservation or energy
capture in the cell.
THE CITRIC ACID CYCLE, GLYCOLYSIS, OXIDATIVE PHOSPHORYLATION
Which of the following compounds have high group transfer
potential?
1. Carbamoyl phosphate
2. 1,3-Bisphosphoglycerate
3. Creatine phosphate
4. Pyrophosphate
A. All statements are correct.
B. Statements 2 & 4 are correct.
C. Statements 1 & 3 are correct.
D. Statements 1, 2 & 3 are correct.
D. Statements 1, 2 & 3 are correct.
- Carbamoyl phosphate
- 1,3-Bisphosphoglycerate
- Creatine phosphate
Metalloflavoproteins are a group of enzymes containing
flavoproteins and a metal ion. Which of these enzymes contain
molybdenum as the metal cofactor?
1. Xanthine oxidase
2. Pyruvate dehydrogenase
3. Aldehyde dehydrogenase
4. Amino Acid oxidase
A. All statements are correct.
B. Statements 1, 2 & 3 are correct.
C. Statements 1 & 3 are correct.
D. Statements 2 & 4 are correct.
C. Statements 1 & 3 are correct.
- Xanthine oxidase - molybdenum containing enzymes
- Aldehyde dehydrogenase - molybdenum & non-heme protein
True of superoxide free radicals.
1. Most important and widespread form under physiologic pH.
2. Can reduce iron-complexes.
3. Are products of normal cellular metabolism especially in the
mitochondria.
4. Superoxide dismutase catalyzes the reaction of superoxide
radicals to hydrogen peroxide and water
A. All statements are correct.
B. Statements 1, 2 & 3 are correct.
C. Statements 2 & 4 are correct.
D. Statements 1 & 3 are correct.
A. All statements are correct.
- Which of the following sites in the electron transport chain are
the likely sources of endogenous radical species?
A. Complex I
B. Complex III
C. Complex IV
D. Complex II
C. Complex IV
The drug Oligomycin significantly reduces the flow of electrons in
the electron transport chain in which of the following complexes?
A. Complex I, III & IV
B. Complex I, II & III
C. Complex I & III
D. Complex II & IV
A. Complex I, III & IV
Oligomycin completely blocks oxidation and phosphorylation by blocking the flow of protons through ATP synthase (Complex V)
In the ATP production, which of the following subunits in the
enzyme complex takes up phosphates consequently forming ATP?
A. Sigma
B. Gamma
C. Beta
D. Alpha
C. Beta
Which of the following is the most important energy shuttle
system found in myofibrils.
1. Glycerophosphate shuttle
2. Malate shuttle
3. Aspartate shuttle
4. Creatine phosphate shuttle
A. Statements 2 & 4 are correct.
B. Statement 4 is correct.
C. Statements 1, 2 & 3 are correct.
D. Statements 1 & 3 are correct.
B. Statement 4 is correct
MELAS (mitochondrial encephalopathy, lactic acidosis and
stroke), a rare genetic disorder affecting the enzymes of which of
the following complexes?
1. Complex III
2. Complex I
3. Complex II
4. Complex IV
A. Statements 2 & 4 are correct.
B. Statement 4 is correct.
C. Statements 1, 2 & 3 are correct.
D. Statements 1 & 3 are correct.
A. Statements 2 & 4 are correct.
- Complex I
- Complex IV
MELAS is inherited condition due to NADH-Q reductase(COMPLEX I) or cytochrome oxidase
(COMPLEX IV)
Which of the following enzymes are found in the mitochondrial
matrix?
1. Citric Acid Cycle enzymes
2. Pyruvate dehydrogenase
3. Fatty acid Beta-oxidation
4. Creatine kinase
A. Statements 2 & 4 are correct.
B. All statements are correct.
C. Statements 1, 2 & 3 are correct.
D. Statements 1 & 3 are correct.
C. Statements 1, 2 & 3 are correct
- Citric Acid Cycle enzymes
- Pyruvate dehydrogenase
- Fatty acid Beta-oxidation
Citric acid cycle enzymes including pyruvate dehydrogenase and B-oxidation enzymes are
found in the mitochondrial matrix
Creatine kinase is found in intermembrane space (together with adenylyl kinase)
Which of the following substances inhibits the Cytochrome P450
hydroxylase cycle.
1. Carboxin
2. Cyanide
3. Hydrogen sulfide
4. Carbon Monoxide
A. Statement 4 is correct.
B. Statements 1, 2 & 3 are correct.
C. Statements 1 & 3 are correct.
D. Statements 2 & 4 are correct.
A. Statement 4 is correct.
- Carbon Monoxide
In the general laws of thermodynamics, what is the most likely
result when delta G is positive?
1. Reaction is complete and is essentially irreversible.
2. Reaction proceeds when there is a net gain of energy.
3. Reaction proceeds spontaneously with a loss of energy.
4. Reaction may least likely occur or not occur at all.
A. Statements 1, 2 & 3 are correct.
B. Statements 1 & 3 are correct.
C. Statements 2 & 4 are correct.
D. Statement 4 is correct.
C. Statements 2 & 4 are correct.
- Reaction proceeds when there is a net gain of energy
- Reaction may least likely occur or not occur at all.
This enzyme is considered a specialized Nucleoside
Monophosphate kinase.
ADENYLYL KINASE or MYOKINASE
nucleoside monophosphate (NMP) kinases catalyze the formation of NDP from the
corresponding monophosphates.
Thus, Adenylyl kinase is a specialized NMP kinase.
This is the form of hemoglobin protein that contains ferric iron
(Fe3+) in the heme prosthetic groups due to oxidation.
A. myoglobin
B. oxyhemoglobin
C. deoxyhemoglobin
D. methemoglobin
D. methemoglobin
In methemoglobinemia, the heme iron is ferric rather than ferrous(metheme), rendering
methemoglobin unable to bind or transport O2.
Which of the following briefly describes myoglobin?
a. low affinity to bind to oxygen
b. higher molecular weight
c. lacks quaternary structure
d. tightly binds to oxygen
d. tightly binds to oxygen
Myoglobin - reservoir of oxygen; tightly binds to O2 more than hemoglobin
Why does the glycolytic pathway continue in the direction of glucose
catabolism?
A. Glycolysis occurs in either direction
B. High levels of ATP keep the pathway going in a forward direction
C. There are essentially three irreversible reactions that act as the
driving force for the pathway
D. The enzymes of glvcolvsis only function in one direction
C. There are essentially three irreversible reactions that act as the
driving force for the pathway
For every one molecule of sugar glucose which is oxidized, __ molecules of
pyruvic acid are produced.
A. 4
B. 3
C. 2
D. 1
C. 2
Glucose + 2NAD + 2ATP + 2ADP + 2P –> 2Pyruvate + 2NADH + 4ATP + 4ADP
In the glycogen synthase reaction, the precursor to glycogen is
A. UTP-glucose
B. glucose-1-P
C. UDP-glucose
D. glucose-6-P
C. UDP-glucose
Glycogenin catalyzes the transfer of a further seven glucose residues from UDPGlc, in
1 → 4 linkage, to form a glycogen primer that is the substrate for glycogen synthase.
The active form of glycogen phosphorylase is phosphorylated, while the
dephosphorylation of which active form occurs?
A. Glycogen hydrolase
B. Glycogen semisynthesis
C. Glycogen dehydrogenase
D. Glycogen synthase
D. Glycogen synthase
The Activities of Glycogen Synthase & Phosphorylase Are Reciprocally Regulated
- Active glycogen synthase a is dephosphorylated and inactive glycogen
synthase b is phosphorylated.
Which of the following is not true of glycolysis?
A. ADP is phosphorylated to ATP via substrate level phosphorylation
B. The pathway oxidises two moles of NAD- to NAD+ for each mole of
glucose that enters - NAD+ -> NADH
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 oxidises two moles of NAD- to NAD+ for each mole of
glucose that enters
its - NAD+ -> NADH
During glycolysis, the major energy-generating step involves
A. Phosphoglycerate kinase
B. Phosphofructokinase
C. Glyceraldehyde-3-dehydrogenase
D. Pyruvate kinase
C. Glyceraldehyde-3-dehydrogenase
Which of the following regulates glycolysis steps?
A. All are correct
B. Phosphofructokinase
C. Pyruvate Kinase
D. Hexose kinase
A. All are correct
Glycogen has:
A. ɑ-1,4 linkage
B. ɑ-1,6 linkages
C. ɑ-1,4 and ß-1,6 linkage
D. ɑ-1,4 and ɑ-1,6 linkage
D. ɑ-1,4 and ɑ-1,6 linkage
What is the other name of glycolysis?
A. TCA pathway
B. HMS pathway
C. EMP pathway
D. None are correct
Embden-Meyerhof-Parnas (EMP) pathway
Which of the following process occurs in glycolysis
A. Reduction
B. Fixation
C. Hydrogenation
D. Oxidation
D. Oxidation
How much ATP is/are used in glycolysis or For complete phosphorylation of a
glucose molecule how many ATP molecules are required?
A. 4
B. 6
C. 8
D. 2
D. 2
Which one of the following is the first step of glycolysis?
A. Dehydrogenation of glucose
B. Phosphorylation of glucose
C. Breakdown of glucose
D. Conversion of glucose into fructose
B. Phosphorylation of glucose
In the pentose phosphate pathway, the major products are:
A. Ribulose and NADH
B. Ribulose and NADPH
C. Ribulose and ATP
D. Ribulose and NAD+
B. Ribulose and NADPH
What is the first reaction of the pentose phosphate pathway?
A. Reduction of ketopentose ribulose 5-phosphate to 6-
phosphogluconate
B. Oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone
C. Oxidation of 6-phosphogluconate to ketopentose ribulose 5-
phosphate
D. Reduction of 6-phospho glucono-δ-lactone to glucose 6-phosphate
B. Oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone
Which of the following statements is correct about oxidative pentose
phosphate pathway?
A. It oxidizes NADPH to NADP+
B. Glucose 6-phosphatase catalyzes the rate limiting reaction of the
pathway
C. The pathway supplies ribose 5-phosphate and NADPH in the
quantities the cell requires
D. It generates NADH
C. The pathway supplies ribose 5-phosphate and NADPH in the
quantities the cell requires
Which one out of the following enzymes acts in the pentose phosphate
pathway?
A. Pyruvate Kinase
B. Glycogen phosphatase
C. 6-phosphogluconate dehydrogenase
D. Aldolase
C. 6-phosphogluconate dehydrogenase
What is the main function of the pentose phosphate pathway?
A. Supply NADH
B. Supply energy
C. Supply NADP+
D. Supply pentoses and NADPH
D. Supply pentoses and NADPH
Which one of the following statements is correct about the pentose
phosphate pathway?
A. It generates 6 moles of CO2 for each mole of glucose consumed
B. Present in plants but not in animals
C. It is a reductive pathway that consumes NADH
D. It generates 38 mol of ATP per mole of glucose consumed
C. It is a reductive pathway that consumes NADH
Which of the following statements is correct about the reductive pentose
phosphate pathway?
A. It is not reversible
B. Transketolase transfers 3 carbon units
C. Pentoses can provide glycolytic intermediates
D. Transaldose transfers 2 carbon units
C. Pentoses can provide glycolytic intermediates
Which of the following statements is false about gluconeogenesis?
A. From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a
carbon source
B. From muscle vigorous muscle activity, lactate can be used as a
carbon source
C. From the hydrolysis of tri-acyl-glycerol, glycerol is converted to
glucose in gluconeogenesis
D. From red blood cells, lactate can be used as a carbon source
A. From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a
carbon source
Which enzyme catalyzes the conversion of pyruvate to oxaloacetate?
A. Pyruvate dehydrogenase
B. Pyruvate Kinase
C. Phosphofructokinase-1
D. Pyruvate carboxylase
D. Pyruvate carboxylase
Oxaloacetate is reduced to malate by
A. Malate dehydrogenase
B. Pyruvate kinase
C. Phosphofructokinase-1
D. Pyruvate carboxylase
A. Malate dehydrogenase
Gluconeogenesis involves the conversion of
A. Phosphoenolpyruvate to glucose
B. Glucose to pyruvate
C. Pyruvate to fructose
D. Pyruvate to glucose
D. Pyruvate to glucose
What is the main source of glucose carbons for gluconeogenesis?
A. Alanine
B. Cysteine
C. Guanine
D. Threonine
A. Alanine
Which of the following statements about gluconeogenesis is correct?
A. Glucose 6-phosphatase hydrolyzes glucose 6-phosphate and is found
in liver and muscle
B. Fructose 1, 6-bisphosphatase converts fructose 1, 6-bisphosphate
into fructose 1-phosphate
C. Pyruvate is first converted to phosphoenolpyruvate by
phosphoenolpyruvate carboxykinase
D. Glucose 6-phosphatase hydrolyzes glucose 6-phosphate to release
glucose into the blood
C. Pyruvate is first converted to phosphoenolpyruvate by
phosphoenolpyruvate carboxykinase
True for metabolism in the brain, EXCEPT:
A. Glycolysis and TCA cycle are the only major processes that the
tissues are capable of undergoing
B. Lactate is the end product of metabolism that is transported out of
the tissues.
C. Ketone bodies accounts for about 20% of the metabolic fuel
D. Utilizes the glycerophosphate shuttle
A. Glycolysis and TCA cycle are the only major processes that the
tissues are capable of undergoing
In the heart, the preferred metabolic fuel to be oxidized first is:
A. Fatty Acids
B. Glucose
C. Lactate
D. Ketone bodies
D. Ketone bodies
Increasing the concentration of hydrogen ions in the intermembrane space
of the mitochondria results in?
A. Increased ATP formation
B. Increasing water in the space
C. Decreased chemiosmosis
D. Decreased oxidative phosphorylation
A. Increased ATP formation
The metabolic process is primarily affected and is the root cause of the
progression of the signs and symptoms of hepatic failure such as coma and
convulsions.
A. Glycolysis
B. Urea cycle
C. Transamination
D. Gluconeogenesis
D. Gluconeogenesis
Hyperammonemia, as occurs in advanced liver disease, leads to loss of consciousness,
coma and convulsions as a result of Citric Acid Cyle. Ammonia depletes CAC
intermediates and inhibits oxidative decarboxylation of a-ketoglutarate. CAC has a central role in Gluconeogenesis, Lipogenesis and Interconversion of Amino Acids
L. a 40 years old male came in for his annual checkup. A blood sample is taken after an overnight
fast. Which one of the following will be at a higher concentration than after she had eaten a meal?
A. Triacy|glycerol
B. Non-esterified fatty acids
C. Glucose
D. Insulin
B. Non-esterified fatty
R, a 37 years old female had her blood taken after she had eaten three
Pandesal and a boiled egg.
Which one of the following will be at a higher concentration than if the blood sample had been
taken after an overnight fast?
A. Glucose
B. Glucagon
C. Non-esterified fatty acids
D. Ketone Bodies
A. Glucose
What intermediate in the glycolysis pathway also serves as an
intermediate in Fatty Acid Synthesis?
A. Phosphoenolpyruvate
B. Phosphoglycerate
C. Fructose-b-phosphate
D. Dihydroxyacetone phosphate
D. Dihydroxyacetone phosphate
What Glycogen Storage Disease deals with a deficiency in Lysosomal
glucosidase?
A. Pompe disease
B. Von Gierke disease
C. Hers disease
D. Tarui disease
A. Pompe disease
Von Gierke dse = Glucose-6-phosphate
Hers dse = Liver phosphorylase
Tarui dse = Muscle and erythrocyte phosphofructokinase 1
The following conditions are expected to decrease as the number of
hours of fasting is prolonged.
1. Plasma insulin
2. Blood glucose
3. Liver glycogen
4 Pasma Amino Acids
A. Statement 4 is correct
B. Statements 2 & 4 are correct
C. Statements 1, 2 & 3 are correct
D. Statements 1 & 3 are correct
C. Statements 1, 2 & 3 are correct
- Plasma insulin
- Blood glucose
- Liver glycogen
The substrates that are mainly used by the fast twitch muscles.
1. Glucose
2. Triacylglycerol
3. Glycogen
4. Lactate
A. Statements 1, 2 & 3 are correct.
B. Statement 4 is correct.
C. Statements 1 & 3 are correct.
D. Statements 2 & 4 are correct.
C. Statements 1 & 3 are correct
1. Glucose
3. Glycogen
Which of the following normal conditions increases the risk for ketosis?
1. Pregnancy
2. Diabetes mellitus
3. Lactation
4 Obesity
A. Statement 4 is correct
B. Statements 2 & 4 are correct
C. Statements 1 & 3 are correct
D. Statements 1, 2 & 3 are correct
D. Statements 1, 2 & 3 are correct
1. Pregnancy
2. Diabetes mellitus
3. Lactation
Triacylglycerol is packaged as chylomicrons and are transported to which
of the different tissues for processing.
1. Adipose
2. Heart muscle
3. Liver
4. Blood
A. Statements 1 & 3 are correct
B. Statements 2 & 4 are correct
C. Statements 1, 2 & 3 are correct
D. Statement 4 is correct
A. Statements 1 & 3 are correct
1. Adipose
3. Liver
The chylomicron remnants are cleared by the liver.
The other major source of long-chain fatty acids is synthesis (lipogenesis) from carbohydrate, in adipose tissue and the liver
For metabolism to be efficient, macronutrients should undergo this
pathway to provide substrates for ATP formation.
1. Electron Transport Chain
2. Glycolysis
3. Oxidative Phosphorylation
4. Krebs cycle
A. Statement 4 Is corre
B. Statements 1 & 3 are correct.
C. Statements 1, 2 & 3 are correct
D. Statements 2 & 4 are correct.
D. Statements 2 & 4 are correct.
2. Glycolysis - NADH
4. Krebs cycle - 3NADH & FADH2
This molecule, when available, can be directly used as a substrate for
gluconeogenesis.
A. Acetyl-CoA
B. Pyruvate
C. Oxaloacetate
D. Triacylglycerol
C. Oxaloacetate
When energy is scarce resulting in metabolism of ketone bodies in
extrahepatic tissues, an alternative pathway catalyzed by Thiophorase is
activated which involves the use of this intermediate in the TCA cycle.
A. Malate
B. Fumarate
C. Oxaloacetate
D. Succinyl CoA
D. Succinyl CoA
The intermediates of the Citric Acid Cycle can be used as substrates for
gluconeogenesis through the key enzyme Phosphoenolpyruvate carboxykinase which utilizes this high-
energy compound.
A. FADH+
B. ATP
C. NADP+
D. GTP
D. GTP
GTP is used for the reaction of phosphoenolpyruvate carboxykinase, thus providing a
link between citric acid cycle activity and gluconeogenesis, to prevent excessive
removal of oxaloacetate for gluconeogenesis, which would impair citric acid cycle activity
Absorption of intact peptides that stimulate antibody response causes an allergic reaction particularly to gluten is one manifestation of this disorder.
A. Cystic Fibrosis
B. Gastric Ulcer
C. Lactose Intolerance
D. Celiac Disease
D. Celiac Disease
The following substance may impair iron absorption in the gut.
A. Milk
B. Vitamin C
C. Alcohol
D. Fruits
A. Milk
This amino acid is considered ketogenic because in prolonged tasting and
starvation, most acetyl-CoA is used for ketogenesis.
A. Tryptophan
B. Isoleucine
C. Phenylalanine
D. Tyrosine
B. Isoleucine
The following has a glycemic index of 1. EXCEPT:
A. Tetrahalose
B. Sucrose
C. Lactose
D. Maltose
B. Sucrose
Gluconeogenesis is the process of synthesizing glucose from non-
carbohydrate precursors, except:
A. Amino acids
B. Glycerol
C. Ketose
D. Lactate
C. Ketose
Which of th following substance inhibits complex III
a. Antimycin A
b. malonate
C. Barbiturate
a. Antimycin A
Which of the following substance acts a competitive inhibitor of complex II??
A. Atractyloside
B. Carbon monoxide
C. Malonate
D. Barbiturate
C. Malonate
What thermodynamic system refers to the heat content of the conducting system?
A. Enthalpy
B. Anabolism
C. Catabolism
D. Entropy
A. Enthalpy
Glycogenolysis is inhibited by
ATP
Which pathway is involved in the production of pentose sugar in DNA and RNA?
a. Glycolysis
b. HMp shunt
c. Glucogenesis
d. Glycogenolysis
b. HMp shunt
other name of Pentose Phosphate Pathway is Hexose Monophosphate Pathway (HMP)
Correct Match
A. Calcium ion - stimulates cAMP
B. Insulin -
C. G6P - Inhibits cAMP
D. Epinephrine - Stimulates cAMP
D. Epinephrine - Stimulates cAMP
During anaerobic conditions, lactate from the muscle goes to the liver through the bloodstream. What will the lactic acid be converted to before going back to the muscle (gist)
A. Glucose
B. Acetyl CoA
C. Glycogen
D. Citrate
A. Glucose
True about gluconeogenesis in humans
A. Conversion of fatty acids to glucose
B. Reduced blood glucose after a fat rich meal
C. Conversion of protein to glucose
D. Requires ATP, but not NADH
A. Conversion of fatty acids to glucose
_______ when there is high source of energy, ________ when there is need or demand of energy
A. Insulin - Cortisol
B. Glucagon - Insulin
C. Insulin - Glucagon
D. Cortisol - Glucagon
C. Insulin - Glucagon
G6PD deficiency. What causes hemolytic anemia?
A. Presence of decreased free radicals in the erythrocytes
B. Presence of increased sodium concentration in the erythrocytes
C. Presence of ATP in the erythrocytes
D. Presence of increased free radicals in the erythrocytes
D. Presence of increased free radicals in the erythrocytes
Which of the following statements regarding the conversion of galactose to glucose is CORRECT?
A. There is both reduction and oxidation reactions.
B. The 1st enzyme to catalyze a reaction is _____________
C. NADH is utilized in the conversion of ___________
D. Epimerase is irreversible.
A. There is both reduction and oxidation reactions.
Conversion of G3P to F3P is a example of which reaction
A. Dehydration
B. Phosphate transfer
C. Isomerase
D. Aldol cleavage
C. Isomerase
Not a product of HMP
a. NADPH
b. Seduloheptulose -5- phosphate
c. G3P
d. F6P
b. Seduloheptulose -5- phosphate
Conversion of xylulose-5-phosphate to ribulose-5-phosphate
Epimerase
Condition in which individuals with cancer, HIV, AIDS and other chronic diseases are undernourished:
A. Anorexia
B. Bulimia
C. Cachexia
D. Wasting
C. Cachexia
Essential amino acids except
A. Isoleucine
B. Histidine
C. Lysine
D. Proline
D. Proline
Overnutrition leads to excess energy intake and contribute to noncommunicable diseases, except:
A. Obesity
B. DM Type II
C. Atherosclerosis
D. Osteoarthritis
D. Osteoarthritis
Beta oxidation occurs in the following tissues except:
A. Liver
B. Heart
C. Slow twitch muscles
D. Kidney
D. Kidney
Matching Type. Regulating Enzymes
A PEPCK
B Glucokinase
C Phosphoglucomutase
D G6PD
E phosphorylase Kinase
- Glycolysis
- Glucogenesis
- Glycogenolysis
- Gluconeogenesis
- HMP Shunt
- B.
- C.
- E.
- A.
- D
- Glycolysis = Glucokinase
- Glucogenesis = Phosphoglucomutase
- Glucogenolysis = phosphorylase kinase
- Gluconeogenesis = PEPCK
- HMP Shunt = g6pd
Matching Type
46. Tauri Disease
47. Von Gierke Disease
48. Pompe Disease
49. McArdle Disease
50. Her’s Disease
- PFK
- G6-Phosphatase
- Lysosomal gluconidase
- Muscle phosphorylase
- Liver phosphorylase
