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146 Cards in this Set
- Front
- Back
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Children with pyruvate dehydrogenase deficiency:
a.exhibit severe neurological defects. b.have elevated levels of myoglobin. c.may be treated with a carbohydrate enhanced diet. d.All of the above. |
a.exhibit severe neurological defects.
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While deficiency of enzymes of the TCA cycle are rare:
a.the first mutation characterized was a malate residue. b.the mitochondrial and cytosolic isozymes of fumarase are derived from different genes. c.Cases of severe deficiency of fumarase in mitochondria and cytosol have been reported. d.The deficiency occurs in the teenage years. |
c.Cases of severe deficiency of fumarase in mitochondria and cytosol have been reported.
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Net synthesis or the formation of glucose from non-carbohydrate substrates is termed:
a.Citric acid cycle b.Glycogenolysis c.Gluconeogenisis d.Is impossible. |
c.Gluconeogenisis
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In the Cori cycle:
a. nitrogen from alanine must be converted to urea. b. Only tissues with aerobic metabolism are involved. c. The same amount of ATP is used in the liver to synthesize glucose as is released through glycolysis leading to no net change in energy. d. A three carbon compound is converted to glucose at the expense of energy from fatty acid oxidation. |
d.A three carbon compound is converted to glucose at the expense of energy from fatty acid oxidation.
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Glucose 6-phosphatase, which is deficient in Von Gierke’s disease is needed for the production of blood glucose from:
a.Lactose. b.liver glycogen. c.fructose. d.all of the above. |
d.all of the above.
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One complete turn of the Citric Acid Cycle yields:
a. 2 CO2, One GTP, 3 NADH and one FADH2. b. One CO2 , 6 ATP, 3 NADH, 4 FADH2 c. eight ATP. d. One Acetyl CoA. |
a. 2 CO2, One GTP, 3 NADH and one FADH2.
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Coenzyme Q is:
a.also known as ubiquinone. b.a benzoquinone isoprenoid. c.a lipophilic electron carrier. d.all of the above. |
d.all of the above.
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Mitochondria:
a.Allow for non-oxidative phosphorylation in the inner membrane. b.Have cristae that allow for decreased surface area to improve efficiency. c.Have an outer membrane of 100% protein. d.Have an inner membrane where electron transport and oxidative phosphorylation occur. |
d.Have an inner membrane where electron transport and oxidative phosphorylation occur.
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The inner mitochondrial membrane contains a transporter for:
a.ATP b.NADH c.NANA d.FADH2 |
a.ATP
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How many NADH’s are produced by glycolysis for each glucose molecule catabolized?
a.One b.Two c.Three d.Four |
b.Two
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How many NADH’s are produced by glycolysis for each glucose molecule catabolized?
a.One b.Two c.Three d.Four |
b.Two
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A competitive inhibitor of pyruvate dehydrogenase is:
a. CO2 b. NAD c. Acetyl CoA d. pyruvate |
c. Acetyl CoA
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Regulation of enzyme catalyzed metabolic pathways can occur through:
a.limiting the substrate. b.Limiting the enzyme. c.Allosteric inhibition. d.All of the above. |
d.All of the above.
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The pentose phosphate pathway:
a.Is completely reversible. b.Produces NADPH by glucose-6-phosphate dehydrogenase. c.Yields pentose-5-phosphate for fatty acid synthesis. d.Converts ribulose-5-phosphate into 5 and 7 carbon carbohydrates. |
d.Converts ribulose-5-phosphate into 5 and 7 carbon carbohydrates.
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Complex III of the electron transport chain:
a. accepts electrons from Complex II by pyruvate b. transfers one electron at a time from cytochrome C to ubiquinone. c. is temperature dependant. d. accepts electrons from Complex II via coenzyme Q. |
d. accepts electrons from Complex II via coenzyme Q.
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Reactive oxygen species may result in:
a.Genetic mutation. b.Convert epoxide to cis double bonds. c.Fuse peptide bonds. d.All of the above. |
a.Genetic mutation.
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Cellular defense against oxidative stress is handled by all of the following except:
a.Uses superoxide dismutase. b.Uses catalase. c.Uses enzymatic systems to inactivate and convert hydroxyl radicals to inactive species. d.All three of the above are mechanisms to defend against oxidative stress. |
c.Uses enzymatic systems to inactivate and convert hydroxyl radicals to inactive species.
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G6PD mutations:
a.Due to heart disease, slightly decrease life span. b.May alter the Km and the Vmax of the enzyme. c.Alter the Citric acid cycle. d.Are affected by aspirin. |
b.May alter the Km and the Vmax of the enzyme.
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Water solubility of metabolites is increased when which of the following is added:
a.D-glucuronic acid. b.Glucose-6- phosphate c.Inorganic phosphate (Pi). d.UDP-glucose. |
a.D-glucuronic acid.
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The conversion of fructose 6-phosphate to fructose 2,6-bisphosphate:
a.Requires ADP to be converted to ATP. b.Is irreversible. c.Requires fructose 2,6-bisphosphatase. d.Requires 6-phosphofructo-2-kinase. |
d.Requires 6-phosphofructo-2-kinase.
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The Alanine and Cori cycles:
a.Both together provide a continuous supply of glucose as a primary energy source. b.Are only functional in tissues that completely oxidize glucose to CO2 & water. c.Occur in the kidney. d.Generate energy in the liver. |
a.Both together provide a continuous supply of glucose as a primary energy source.
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All amino acids can supply carbon for gluconeogenesis except:
a.glycine and leucine. b.Leucine and Lysine. c.Cirtuline and NADH. d.NADPH and NADP. |
b.Leucine and Lysine.
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Glycogen is:
a.A polymer of glucose stored only in muscle. b.A fuel reserve for maintenance of blood glucose concentrations. c.Is broken down by glycogenesis. d.Decreased after meals. |
b.A fuel reserve for maintenance of blood glucose concentrations.
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Glycogen branching enzyme is important since:
a.It allows glucogen to be released rapidly. b.It allows glucose to be rapidly released. c.It does not require inorganic phosphate. d.All of the above. |
b.It allows glucose to be rapidly released.
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Regulation of enzymes can occur by all of the following except:
a.Limited substrate availability. b.Having different isoforms of the enzymes. c.Covalent modification of the enzyme. d.Through interactions with non-competitive binding sites. |
b.Having different isoforms of the enzymes.
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PFK-1 is:
a.Allosterically inhibited by NADH and citrate. b.Inhibited by AMP c.Inhibited by ATP. d.Inhibited by ADP. |
c.Inhibited by ATP.
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Types of reactions in the glycolytic pathway include all except:
a.Dehydration. b.Ethyl cleavage. c.Phosphoryl shifts. d.Phosphorol transfer |
b.Ethyl cleavage.
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The first step in the liver’s metabolism of fructose is:
a.Isomerization to glucose. b.Phosphorylation to fructose 1,6-biphosphate. c.Phosphorylation to fructose 1-phosphate. d.Cleavage by aldolase. |
c.Phosphorylation to fructose 1-phosphate.
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Glucose 6-phosphate`, which is deficient in Von Gierke’s disease is needed for the
Production of blood glucose from: a.Liver glycogen. b.Fructose. c.Amino acid carbon chains. d.All of the above. |
d.All of the above.
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All of the following are true about glucuronic acid except:
a.it is a precursor of ascorbic acid in humans. b.It is a charged molecule at physiological pH. c.It can be ultimately converted to xyulose 5-phosphate and then enter the pentose phosphate pathway. d.All of the above are true. |
a.it is a precursor of ascorbic acid in humans.
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All are precursors of Acetyl CoA except:
a.Glycogen. b.Triglyceride c.Inorganic phosphate. (Pi) d.Protein. |
c.Inorganic phosphate. (Pi)
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31.Acetyl CoA and NADH:
a.Are non-competitive inhibitors in the regulation of pyruvate dehydrogenase. b.Are potent inhibitors of a kinase. c.Do not activate protein kinase. d.Are competitive inhibitors of the regulation of pyruvate dehydrogenase. |
d.Are competitive inhibitors of the regulation of pyruvate dehydrogenase.
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True/False
Enzymes of the citric acid cycle are located only in the inner membrane of the mitochondria. |
False.
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True/False
Glucuronic acid is formed by the oxidation of UDP-glucose. |
True
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True/False
Conversion of glucose to lactate yields a net of two molecules of ATP whereas synthesis of glucose from lactate requires six molecules of ATP. |
True
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True/False
The majority of proteins in the electron transport chain are encoded in mitochondrial DNA and synthesized in the matrix. |
False. encoded in nuclear DNA and synthesized in the cytosol.
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True/False
The alanine malate shuttle transports cystolic reducing electrons into the mitochondrial matrix. |
False. asparate malate shuttle.
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True/False
Glucose is converted to glucose 6-phosphate by hexokinase. |
True
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True/False
There are a number of well-characterized glycogen storage diseases, all due to inherited defects. |
True
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True/False
Type three glycogen storage disease is caused by deficiency of glycogen debranching enzyme. |
True
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True/False
Type V glycogen storage disease is caused by an excess of muscle phosphoylase. |
False. absence of muscle phosphoylase.
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True/False
Lactic acidosis is characterized by elevated blood lactate levels, usually greater than 5mM. |
True
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True/False
The stepwise transfer of electrons to oxygen results in formation of superoxide anions, then hydrogen peroxide, and finally hydroxyl free radicals. |
True
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True/False
Complex I, II and III all pump protons. |
False. Complex I, III and IV
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True/False
The inner membrane of the mitochondria contains all of the enzymes . |
False
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True/False
Pyruvate dehydrogenase is a multi-enzyme complex. |
True
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True/False
The capacity for hepatic glucose synthesis from lactate and alanine is limited in newborn babies. |
True
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True/False
In gluconeogenesis glucose can by synthesized from lactate and requires ATP. |
True
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True/False
Consumption of alcohol especially by an undernourished person can cause hypoglycemia. |
True
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True/False
Catabolism degrades complex molecules into smaller molecules with the expenditure of energy. |
False. no energy needed.
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What kind of energy form does anabolism require?
a. NADPH b. ATP c. ADP d. NADH e. Two of the above. |
e. Two of the above. (ATP and NADH)
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(Catabolism/anabolism) results in thermogenesis.
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anabolism
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Energy production comes from (catabolism/anabolism).
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catabolism
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In order to make NADH as an energy form hydrides must be transferred from substrates by:
a. Transferase b. Dehydrogenase c. Lyase d. Kinase |
b. Dehydrogenase
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The First Law of Thermodynamics states that:
a.A process can occur spontaneously only if the sum of the entropies of the systems and its surroundings increases. b.Energy can neither be created nor destroyed. c.The energy of a system and the environment is constant. d.Two of the above. e.All of the above. |
d.Two of the above.
(Energy can neither be created nor destroyed. The energy of a system and the environment is constant.) |
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True/False
The change in energy of a reaction only depends on the energy at the end minus the energy at the beginning. |
True
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True/False
The energy difference in a chemical reaction is independent of the path of the transformation. |
True
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1.)The Second Law of Thermodynamics discusses the:
a.Change in energy b.Change in temperature c.Change in entropy d.None of the above |
c.Change in entropy
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True/False
Because the entropy must be constantly increasing, the formation of an ordered complex molecule is not feasible. |
False. decrease in entropy is offset by entropy of surroundings.
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Which of the following is TRUE?
a.Entropy changes are not readily measured b.Entropy changes requires the knowledge of the entropy change of the surroundings and system. c.It is used as a predictor of spontaneity. d.A & B e.All of the above. |
d.A & B
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What does change in free energy depend on?
a.Change in enthalpy b.Change in entropy c.Both d.Neither |
c.Both
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A reaction can occur spontaneously if ΔG is (positive/negative/zero).
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negative
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No net change can occur if:
a.ΔG > 0 b.ΔG < 0 c.ΔG = 0 d.ΔG > 0 |
c.ΔG = 0
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True/False
ΔG provides no information about the rate of the reaction. |
True
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(Endergonic/exergonic) reactions releases energy in the form of (ATP/NADH/Pyruvate) while (endergonic/exergonic) reactions requires an input of energy.
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Exergonic. ATP. Endergonic.
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When an unfavorable reaction occurs:
a.The reaction will not proceed b.It can proceed when coupled with a favorable reaction c.It can proceed by increasing the temperature of the surroundings d.It will proceed over a long period of time |
b. It can proceed when coupled with a favorable reaction
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Energy rich compounds tend to have a:
a.Phosphate bond b.Positive ΔG c.Negative ΔG d.A & C |
d.A & C
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Acetyl CoA exists in a (oxidized/reduced) form ___________ and forms (high/low) energy (amide/thioester/ester) bonds with acyl groups.
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reduced. CoASH. high. thioester.
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From what is Acetyl CoA produced?
a.Glycogen b.Triacylglycerides c.Amino acids d.All of the above are possible sources. |
d.All of the above are possible sources.
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The enzyme (pyruvate dehydrogenase/lactate dehydrogenase) is used to convert CoASH into Acetyl CoA along with the coenzyme (pyruvate/lactate) and cofactor (NAD+/NADPH/ATP).
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pyruvate dehydrogenase. pyruvate. NAD+.
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True/False
The protein kinase is crucial in regulating lactate dehydrogenase in Acetyl CoA production. |
False. kinase is involved in regulating pyruvate dehydrogenase.
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What inhibits protein kinase?
a.Calcium ions b.Acetyl CoA & NADH c.CoASH d.Pyruvate e.Two of the above |
e.Two of the above (CoASH and Pyruvate)
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1.)The action of phosphatase:
a.Dephosphorylates Pyruvate Dehydrogenase and activates it. b.Phosphorylates pyruvate dehydrogenase and inactivates it. c.Is activating by Calcium ions d.A & C |
d.A & C
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Acetyl CoA consists of ___ carbons.
a.2 b.3 c.6 d.None of the above. |
a.2
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One complete turn of the TCA cycle yields ___ GTP, ___ FADH2, ___ CO2, and ___ NADH.
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1. 1. 2. 3.
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1.)How many ATPs are formed by the electron transport chain?
a.6 b.2 c.4 d.9 e.37 |
d.9
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True/False
Citrate formation from Acetyl CoA and Oxaloacetate has a high energy barrier and requires ATP to proceed. |
False. Citrate formation has a negative ΔG and is favored.
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True/False
Oxaloacetate concentration in the mitochondria is very low, even below the Km value of the enzyme. |
True
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What are the 3 most regulated enzymes in the TCA cycle?
a. Aconitase, Citrate Synthase, Succinate Dehydrogenase. b. Citrate Synthase, alpha-ketoglutarate dehydrogenase, Aconistase c. Citrate synthase, Succinyl CoA synthetase, Isocitrate dehydrogenase. d. Citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase. |
d. Citrate synthase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase.
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In the TCA cycle as ATP is used, NADH will (increase/decrease) and FADH2 will (increase/decrease).
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increase. decrease.
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What converts citrate to isocitrate?
a.Aconitase b.Citrate dehydrogenase c.Isocitrate dehydrogenase d.Citrate synthase. |
a.Aconitase
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Oxidative decarboxylation occurs when:
a. The introduction of water into the TCA cycle generates the formation of hydrogen ions and O2 gas. b. A hydroxyl group is placed next to a carboxyl group and then they leave as CO2. c. When 32 molecules of ATP is produced from the TCA cycle. d. All of the above. |
b.A hydroxyl group is placed next to a carboxyl group and then they leave as CO2.
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Which molecule undergoes oxidative decarboxylation to form alpha-ketoglutarate?
a.Isocitrate dehydrogenase after conversion to aconitase. b.Citrate after conversion to isocitrate c.Isocitrate after conversion to oxalosuccinate d. None of the above |
c.Isocitrate after conversion to oxalosuccinate
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The enzyme analogous to pyruvate dehydrogenase multienzyme complex is:
a.Citrate synthase. b.Alpha-Ketoglutarate dehydrogenase. c.Succinate dehydrogenase d.Isocitrate dehydrogenase |
b.Alpha-Ketoglutarate dehydrogenase.
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Which compound is similar to Acetyl ester in that it has an energy rich thiol ester bond?
a.Alpha-ketoglutarate. b.Isocitrate c.Succinyl CoA d.Malate |
c. Succinyl CoA
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Which is a coenzyme of alpha-ketoglutarate dehydrogenase?
a. Thiamine pyrophosphate b. Lipoic acid c. CoASH d. FAD & NAD+ e. All of the above |
e. All of the above
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In converting alpha-ketoglutarte to succinyl CoA the rate of the reaction depends on (substrate/enzyme/coenzyme) concentration. Afterwards Succinyl CoA can be used in the biosynthesis of ___________.
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coenzyme. heme.
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1.)What is produced in the Succinyl CoA to Succinate conversion?
a.GDP b.GTP c.CoASH d.Enzyme phosphate e.B & C f.All of the above |
f.All of the above except A
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1.)Has a histidine and 1 subunit containing 3 iron-sulfur centers.
a.Alpha-ketoglutarate. b.Succinyl CoA synthetase c.Aconitase d.Succinate dehydrogenase |
d.Succinate dehydrogenase
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In succinate dehydrogenase the electrons are transferred from the substrate ______________ through (FAD/FADH2/NAD/NADPH) to the iron-sulfur center and eventually transferred to ________________ also known as ubiquinone.
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succinate. FAD. coenzyme Q.
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True/False
The reaction converting fumarate to L-Malate by the enzyme fumarase is freely reversible. |
True
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Which of the following is in the correct sequence?
a.Oxaloacetate -> L-Malate -> Citrate b.Citrate -> Oxaloacetate -> L-Malate c.L-Malate -> Oxaloacetate -> Citrate. |
c.L-Malate -> Oxaloacetate -> Citrate.
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True/False
The reaction converting L-Malate by malate dehydrogenase to oxaloacetate is favored toward oxaloacetate, since it is driven towards the citrate synthase reaction. |
False. ΔG is positive so reverse reaction to L-Malate is favored. Reaction is pulled forward by citrate synthase reaction which requires oxaloacetate.
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True/False
The two byproducts of the TCA cycle are H2O and CO2. |
True
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1.)Every turn of the TCA cycle yields:
a.6 ATP b.8 ATP c.10 ATP d.12 ATP |
c.10 ATP
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True/False
Enzymes and intermediates found in the TCA cycle functions exclusively in the mitochondria. |
False. TCA intermediates are also precursors for amino acids, fatty acids, and glucose synthesis.
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The most important anaplerotic reaction that supplies 4-5 carbon acids for the TCA cycle is:
a.Pyruvate carboxylase b.Citrate synthase c.Alpha-ketoglutarate dehydrogenase d.Isocitrate dehydrogenase |
a.Pyruvate carboxylase
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Match the following: (More than one correct answer)
Citrate synthase: a.Inhibited by ATP b.Inhibited by NADH c.Inhibited by Succinyl CoA d.Inhibited by Long Chain Acyl CoA e.Stimulated by ADP f.Inhibited by GTP. g.Stimulated by Ca2+ |
a, b, c, d
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Match the following: (More than one correct answer)
Isocitrate dehydrogenase: a.Inhibited by ATP b.Inhibited by NADH c.Inhibited by Succinyl CoA d.Inhibited by Long Chain Acyl CoA e.Stimulated by ADP f.Inhibited by GTP. g.Stimulated by Ca2+ |
a, b, e
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Match the following: (More than one correct answer)
Alpha-ketoglutarate dehydrogenase: a.Inhibited by ATP b.Inhibited by NADH c.Inhibited by Succinyl CoA d.Inhibited by Long Chain Acyl CoA e.Stimulated by ADP f.Inhibited by GTP. g.Stimulated by Ca2+ |
a, b, c, f, g
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A bond may be "high energy" for any of the following reasons except:
a. products of its cleavage are more resonance stabilized than the original compound b. the bond is unusually stable, requiring a large energy input to cleave it c. electrostatic repulsion is relieved when the bond is cleaved d. a cleavage product may be unstable, tautomerizing to a more stable form e. the bond may be strained |
b. the bond is unusually stable, requiring a large energy input to cleave it
High-energy does not refer to high energy of formation (bond stability). A "high-energy" bond is so designated because it has a high free energy of hydrolysis. |
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At which of the following enzyme-catalyzed steps of the tricarboxylic acid cycle does net incorporation of the elements of water into an intermediate of the cycle occur:
a. aconitase b. citrate synthase c. malate dehydrogenase d. succinate dehydrogenate e. succinyl CoA snythase |
b. citrate synthase
Water is required to hydrolyze the thioester bond of acetyl CoA. |
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All of the following tricarboxylic acid cycle intermediates may be added or removed by other metabolic pathways except:
a. citrate b. fumarate c. isocitrate d. alpha-ketoglutarate e. oxaloacetate |
c. isocitrate
Clearly most of the tricarboxylic acid cycle intermediates play multiple roles in the body. |
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The inner mitochondrial membrane contains a transporter for:
a. NADH b. acetyl CoA c. GTP d. ATP e. NADPH |
d. ATP
ATP and ADP are transported in opposite directions. |
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ATP synthase (also known as Complex V) consists of two domains, F1 and F0:
a. F1 and F0 are both integral membrane protein complexes of the outer membrane b. F1 domain provides a channel for translocation of protons across the membrane c. F1 binds ATP but not ADP d. only the F0 region contains more than one subunit |
d. only the F0 region contains more than one subunit
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The active form of pyruvate dehydrogenase is favored by the influence of all of the following on pyruvate deyhydrogenase except:
a. low Ca2++ b. low acetyl CoA/CoASH c. high pyruvate d. low NADH/NAD+ |
a. low Ca2++
High Ca++ favors the active form of dehydrogenase but by activating the phosphatase. |
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Suppose the specific defect were a mutant pyruvate dehydrogenase (the first catalytic subunit) with poor binding of its prosthetic group. In this type of defect, sometimes greatly increasing the dietary precursor of the prosthetic group may be helpful. In this case, increasing which of the following may be helpful?
a. lipoic acid b. niacin (for NAD) c. pantothenic acid (for CoA) d. riboflavin (for FAD) e. thamine (for TPP) |
e. thamine (for TPP)
TPP is the cofactor for the first reaction which decarboxylates pyruvate. |
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Cyanide:
a. only minimally inhibits the electron transport chain because cytochrome oxidase is a terminal component of the chain b. inhibits mitochondrial respiration but energy production is unaffected c. also binds to the copper of cytochrome oxidase d. binds to Fe3+ of cytochrome a3 e. poisoning could also be reversed by increasing O2 concentration |
d. binds to Fe3+ of cytochrome a3
This is why methemoglobin is an effective antidote since it also has an Fe3+. |
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If cyanide is added to tightly coupled mitochondria that are actively oxidizing succinate:
a. subsequent addition of 2,4-dinitrophenol will cause ATP hydrolysis b. subsequent addition of 2,4-dinitrophenol will restore succinate oxidation c. electron flow will cease, but ATP synthesis will continue d. electron flow will cease, but ATP synthesis can be restored by addition of 2,4-dinitrophenol e. subsequent addition of 2,4-dinitrophenol and the phosphorylation inhibitor, oligomycin, will cause ATP hydrolysis. |
a. subsequent addition of 2,4-dinitrophenol will cause ATP hydrolysis
Cyanide inhibits electron transport at site III, blocking electron flow throughout the system. In coupled mitochondria, ATP synthesis cease too. Addition of the uncoupledr permits the mitochondrial ATPase to operate and it catalyzes the favorable ATP hydrolysis reaction unless it is inhibited by a phosphorylation inhibitor such as oligomycin. |
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NAD+ can be regenerated in the cytoplasm if NADH reacts with any of the following except:
a. pyruvate b. dihydroxyacetone phosphate c. oxalacetone d. the flavin bound to NADH dehydrogenase |
d. the flavin bound to NADH dehydrogenase
The flavin is mitochondrial |
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Glucokinase:
a. has a S0.5 greater than normal blood glucose concentration b. is found in muscle c. is inhibited by glucose 6-phosphate d. is also known as the GLUT-2 protein e. has glucose 6-phosphatase activity as well as kinase activity |
a. has a S0.5 greater than normal blood glucose concentration
Blood glucose is 5 mM. S0.5 of glucokinase is 7 mM. |
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All of the following are correct except:
a. reactive oxygen species (oxygen radicals) result when there is a concerted addition of 4 electrons at a time to O2 b. superoxide anion (O2-) and hydroxyl radical (.OH) are two forms of reactive oxygen c. superoxide dismutase is a naturally occuring enzyme that protects against damage by converting O2- to H2O2 d. reactive oxygen species damage phospholipids, proteins and nucleic acids e. glutathione protects against H2O2 by reducing it to water |
a. reactive oxygen species (oxygen radicals) result when there is a concerted addition of 4 electrons at a time to O2
Four electron transfer produces water. Oxygen radicals occur when electrons are added stepwise to O2. |
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All of the following result from ischemia except:
a. decrease in intracellular ATP b. decrease in intracellular creatine phosphate c. decrease in NADH/NAD+ d. lactic acidosis e. depletion of cellular glycogen |
c. decrease in NADH/NAD+
Inhibition of electron transport because of low O2 prevents reoxidation of NADH so the NADH/NAD+ increases |
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6-Phosphofructo-1-kinase activity can be decreased by all of the following except:
a. ATP at high concentrations b. citrate c. AMP d. low PH e. decreased concentration of fructose 2,6-biphosphate |
c. AMP
AMP is an allosteric regulator that relieves inhibition by ATP |
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Which of the following supports gluconeogenesis?
a. alpha-ketoglutarate + apartate <--> glutamate + oxaloacetate b. pyruvate + ATP + HCO3- <--> oxaloacetate + ADP + Pi + H+ c. acteyl CoA + oxaloacetate + H2O <--> citrate + CoA d. leucine degradation e. lysine degradation |
b. pyruvate + ATP + HCO3- <--> oxaloacetate + ADP + Pi + H+
This reaction is on the direct route of conversion of pyruvate to glucose |
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In the Cori Cycle:
a. only tissues with aerobic metabolism (mitochondria and O2) are involved b. a three-carbon compound arising from glycolysis is converted to glucose at the expense of energy from fatty acid oxidation c. glucose is converted to pyruvate in anaerobic tissues, and this pyruvate returns to the liver, where it is converted to glucose d. nitrogen from alanine must be converted to urea, increasing the amount of energy required to drive the process |
b. a three-carbon compound arising from glycolysis is converted to glucose at the expense of energy from fatty acid oxidation
The liver derives the energy required for gluconeogenesis from aerobic oxidation of fatty acids. |
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When blood glucagon rises, which of the following hepatic enzyme activities falls?
a. adenylate cyclase b. protein kinase c. 6-phosphofructo-2-kinase d. fructose 1,6-biphosphatase |
c. 6-phosphofructo-2-kinase
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McArdle's patients:
a. fail to synthesize glycogen appropriately b. do not repsond to glucagon in a normal fashion c. show a reduced state of glycolysis during exercise d. have impaired tricarboxylic acid cycle e. has reduced lactic acid because all of the lactate is converted to pyruvate |
c. show a reduced state of glycolysis during exercise
Muscles use glucose from glycogen as the primary substrate for glycolysis during exercise. Lack of phosphorylase prevents the degradation of glycogen. |
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Glucose 6-phosphatase, which is deficient in Von Gierke's disease, is necessary for the production of blood glucose from:
a. liver glycogen b. fructose c. amino acid carbon chains d. lactose e. all of the above |
e. all of the above
To get into the blood, glucose must be free, not phosphorylated |
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Ca2+ increases glycogenolysis by:
a. activating phophorylase kinase b, even in the absence of cAMP b. binding to phosphorylase b c. activating phosphoprotein phosphatase d. inhibiting phosphoprotein phosphatase e. protecting cAMP from degradation |
a. activating phophorylase kinase b, even in the absence of cAMP
The gamma subunit of phosphorylkinase is a calmodulin-type protein. Both a and b forms of the enzyme are activated by Ca2+ |
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Phosphorylation-dephosphorylation and allosteric activation of enzymes play roles in stimulating glycogen degradation. All of the following result in enzyme activation except:
a. phosphorylation of phosphorylase kinase b. binding of AMP to phosphorylase b c. phosphorylation of phosphorylase d. phosphorylation of protein kinase a e. dephosphorylation of glycogen synthase |
d. phosphorylation of protein kinase a
Protein kinase a catalyzes phosphorylations but is activated by binding cAMP |
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The first step in the liver's metabolism of fructose is:
a. isomerization of glucose b. phosphorylation to fructose 1,6-bisphosphate by ATP c. phosphorylation to fructose 1-phosphate by ATP d. phosphorylation to fructose 6-phosphate by ATP e. cleavage by aldolase |
c. phosphorylation to fructose 1-phosphate by ATP
The ADP formed is converted to ATP at the expense of Pi. Inability to further metabolize fructose 1-phosphate results in depletion of Pi. |
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The products initially produced by aldolase action on the substrate formed from fructose are:
a. two molecules of dihydroxyacetone phosphate b. two molecules of glyceraldehyde 3-phosphate c. two molecules of lactate d. dihydroxyacetone phosphate and glyceraldehyde 3-phosphate e. dihydroxyacetone phosphate and glyceraldehyde |
e. dihydroxyacetone phosphate and glyceraldehyde
Glyceraldehyde can be converted to glyceraldehyde 3-phosphate so both products feed into the glycolytic pathway or gluconeogenesis |
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All of the following are true about glucuronic acid except:
a. it is a charged molecule at physiological pH b. as a UDP derivative, it can be decarboxylated to a component used in proteoglycan synthesis c. it is a precursor to ascorbic acid in humans d. its formation from glucose is under feedback control by a UDP-linked intermediate e. it can ultimately be converted to xylulose 5-phosphate and thus enter the pentose phosphate pathway |
c. it is a precursor to ascorbic acid in humans
Man does not make ascorbic acid |
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NADPH/NAD+ is maintained at a high level in the cells primarily by:
a. lactate dehydrogenase b. the combined actions of glucose 6-phosphate dehydrogenase and glucolactonase c. the action of the electron transport chain d. shuttle mechanisms such as alpha-glycerophosphate dehydrogenase shuttle e. the combined actions of transketolase and transaldolase |
b. the combined actions of glucose 6-phosphate dehydrogenase and glucolactonase
Although the glucose 6-phosphate dehydrogenase reaction, specific for NADP, is reversible, hydrolysis of the lactone assures that the overall equilibrium lies far in the direction of NADPH |
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If a cell requires more NADPH than ribose 5-phosphate:
a. only the first phase of the pentose phosphate pathway would occur b. glycolytic intermediates would flow into the reversible phase of the pentose phosphate pathway c. there would be sugar interconversion but no net release of carbons from glucose 6-phosphate d. the equivalent of the carbon atoms of glucose 6-phosphate would be released as 6 CO2 e. only part of this need could be met by the pentose pathway, and the rest would have to be supplied by another pathway |
d. the equivalent of the carbon atoms of glucose 6-phosphate would be released as 6 CO2
Glucose 6-phosphate yields ribose 5-phosphate + CO2 in the oxidative phase. If this is multiplied by six, the six ribose 5-phosphates can be rearranged to five glucose 6-phosphates by the second, reversible phase. |
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Reducing power, in the form of either NADH or FADH2, is generated at which of the following metabolic stages (check all that apply)?
a. Glycolysis b. The Pyruvate Dehydrogenase Complex c. The Citric Acid Cycle d. Oxidative Phosphorylation |
d. Oxidative Phosphorylation
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Which of the following describes the signal transduction process?
a.One molecule of cAMP is produced for every hormone molecule that binds to its cellular receptor. b.Addiction of a phosphate group to an enzyme by a kinase always results in a more active enzyme. c.All signal transduction cascades lead to change in the expression of cellular genes. d.Inhibitory and stimulatory signals interact to regulate a cell’s activity |
d. Inhibitory and stimulatory signals interact to regulate a cell’s activity
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3) In a certain individual, the receptor for epinephrine contains a mutation that reduces its affinity for epinephrine. Which would you expect to occur in response to environmental stress?
a. No effect; the mutation is unimportant b. cAMP levels would be reduced in comparison to a cell with a normal receptor c. cAMP levels would be elevated in comparison to a cell with a normal receptor. d. Glycogen breakdown would accelerate |
b. cAMP levels would be reduced in comparison to a cell with a normal receptor
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Caffeine blocks the breakdown of cAMP. Caffeine would also be expected to do which of the following?
a.Increase protein kinase A activity b.Decrease protein kinase A activity c.Increase the binding of GTP by G proteins d.Block the activation of inhibitory receptors |
a. Increase protein kinase A activity
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Which of the following does not describe metabolism?
a.The reverse direction of a metabolic pathway occurs at a different rate from forward direction b.Metabolic pathways can be turned off when the level of product becomes too high c.Some cell types completely lack metabolic pathways that other cell types utilize d.The last step of a metabolic pathway regulates flow rate though the entire pathway |
d. The last step of a metabolic pathway regulates flow rate though the entire pathway
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6) Which of the following is NOT a molecule used by cells for energy?
a. ATP b. NADH c. CO2 d. FADH2 |
c. CO2
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Which of the following would describe an anabolic pathway?
a. An intermediate in the pathway can be formed from three distinct substrates and produces a single final product b. ATP energy is produced by the process c. ADP levels rise as a result of the process d. NADH levels rise drastically with increased flux through the pathway. |
c. ADP levels rise as a result of the process
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The inhibitor rotenone blocks transfer of electrons from the Fe-S protein in Complex I to CoQ. Which of the following processes would most likely be lessened as well?
a. Substrate level phosphorylation of ADP to ATP by ATP synthase b. NADH production c. FADH2 production d. Reduction of oxygen by Complex IV e. Entry of FADH2 into the electron transport chain |
d. Reduction of oxygen by Complex IV
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Base upon your knowledge of regulation of metabolic pathways, which of the following would you expect to occur as ADP levels rise in the mitochondria?
a. Electron transport would come to a halt b. ATP synthase activity would increase c. Pumping of electrons into the inter membrane space would slow d. Catabolism of glucose would cease e. Glycogen production would increase |
b. ATP synthase activity would increase
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10) Which of the following would most likely occur if the mitochondrial inner membrane was freely permeable to small ions?
a. The mitochondrial membrane would rupture b. ATP synthesis rates would increase dramatically c. Electron transport would be uncoupled from ATP synthesis d. The pH in the intermembrane space would become very acidic e. The Malate-asparate shuttle system would be more productive |
c. Electron transport would be uncoupled from ATP synthesis
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Which is the correct net reaction for the conversion of glucose to lactate in muscle?
a. Glucose + 2ADP + 2NAD+ + 2Pi yields 2 lactate + 2ATP + 2NAHD + H+ b. Glucose + ADP + NAD+ +2Pi yields 2 lactate + ATP + NADH + H+ c. Glucose +2 ADP + 2Pi yields 2 lactate + 2 ATP + 2H2O d. Glucose + ADP + NAD+ + 2Pi yields lactate + ATP + NADPH + H+ |
c. Glucose +2 ADP + 2Pi yields 2 lactate + 2 ATP + 2H2O
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Which is the correct net reaction for the formation of glucose from lactate in the liver?
a. 2 lactate + 2ATP + 2GTP + 4H2O yields glucose + 2ADP + 2GDP + 4Pi b. 2 lactate + 4ATP + 2GTP + 4H2O yields glucose + 2ADP + 2GDP + 6Pi c. 2 lactate + 6ATP + 6H2O yields glucose + 6ADP + 6Pi d. 2 lactate + 4ATP + 2GDP + 6H2O yields glucose + 4ADP + 2GDP + 6Pi |
c. 2 lactate + 6ATP + 6H2O yields glucose + 6ADP + 6Pi
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What is the correct net reaction for the overall Cori Cycle?
a. 2ATP + 2GTP + 4H2O yields 2ADP + 2GDP + 4Pi b. 4ATP + 2GTP + 6H2O yields 4ADP + 2GDP + 6Pi c. 6ATP + 2GTP + 8H2O yields 6ADP + 2GDP + 8Pi d. ATP + 3GTP + 4H2O yields ADP + 3GDP + 4Pi |
a. 2ATP + 2GTP + 4H2O yields 2ADP + 2GDP + 4Pi
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Can you recall the metabolic source for the acetyl CoA that can be ultimately converted to cholesterol?
a. Citric acid cycle b. Glycolysis c. Oxidative phosphorylation d. Pentose-phosphate shunt e. Fatty acid oxidation |
b. Glycolysis
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True/False
Lipitor will alleviate the effect of ingesting large amounts of high cholesterol foods |
False
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True/False
250mg total cholesterol/100ml of blood is considered “low risk” for cardiovascular disease |
False
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True/False
Exercise will increase the levels of HDL cholesterol in your blood |
True
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True/False
Mevinolin acts by increasing HMG CoA reductase activity. |
False
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What is the name of the water soluble enzyme that degrades triacylglycerol into fatty acids and glycerol in the small intestine?
a. Cholate b. Glycocholate c. Pancreatic lipase d. Glycerol |
c. Pancreatic lipase
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What is the name of the carrier molecule in the bloodstream that transports the fatty acids from the adipocytes to the myocytes for oxidation to ATP?
a. Serum albumin b. Triacylglycerol lipase c. Glycocholate d. Protein kinase |
a. Serum albumin
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