Exam 3 Problem Roulette Flashcards by Hadley Katzman

Where in the cell does Glycolysis take place in mammals?

In the Cytosol, since the enzymes are soluble

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Which of the following is NOT an important catabolic product of pyruvate formed by glycolysis (i.e. what are the fates of pyruvate from glycolysis?)?

Glucose

Acetyl-CoA

Ethanol plus carbon dioxide

Lactate

Glucose

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How many hexose phosphates are generated from 18 pentose phosphates during the non-oxidative phase of the Pentose Phosphate pathway?

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Select the TRUE statement.

Gluconeogenesis in humans

Can take fatty acids to glucose.

helps decrease blood glucose after a carbohydrate-rich lunch

Is activated by the hormone insulin

requires PFK-1.

Cannot take acetyl CoA to glucose

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How many ATP molecules are required to convert one Glucose molecule to two 1,3-bisphosphoglycerate molecules?

None, ADP is required

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What is the substrate of glycogen synthase for glycogen synthesis (that is, making glycogen longer)?

Glucose 1-phosphate

Glucose

Glucose 6-phosphate

Glucose 1,3-bisphosphate

UDP-glucose

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The reaction in glycolysis that converts a ketose form to an aldose form is catalyzed by:

Phosphohexose isomerase

Phosphoglycerate mutase

Pyruvate kinase

Aldolase

Triose phosphate isomerase

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The conversion of glucose-6-phosphate to ribulose-5-phosphate involves:

Hydrolysis of glucose-6-phosphate

Reduction of NADP+

Isomerization of glucose-6-phosphate

Carboxylation of glucose-6-phosphate

Reduction of glucose-6-phosphate

Reduction of NADP+

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When a free glucose molecule first enters a cell (via the glucose transporter), the most likely first reaction catalyzed is:

Dehydration generating fructose

Phosphorylation of the C6 carbon using ATP

Isomerization into fructose

Phosphorylation of the C1 carbon using ATP

Dehydrogenation generating NADH

Phosphorylation of the C6 carbon using ATP

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Glycolysis conserves metabolic energy in two different molecules. What is the correct pair of molecules and their net amounts produced by glycolysis?

4 ATP + 2 NADPH

2 ATP + 2 NADH

2 ATP + 4 NADH

4 ATP + 2 NADH

2 ATP + 2 NADPH

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Which of the below helps convert glucose into a reactant for glycogen synthase?

cyclic AMP

CTP

GTP

UTP

ATP

UTP

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The purpose of the oxidative phase of the pentose phosphate pathway is to:

oxidize glucose 6P, reduce NAD+, and as a result help generate energy (ATP) through oxidative phosphorylation

convert 6 ribose phosphates to 5 hexose phosphates

facilitate the Cori cycle.

provide intermediates for the citric acid cycle.

generate pentoses for the synthesis of nucleotides and nucleic acids.

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The electron acceptor in the steps that convert pyruvate to ethanol is:

pyruvate.

acetaldehyde.

NAD+.

TPP

ethanol.

acetaldehyde.

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Which reaction of Glycolysis is unusual in that is uses inorganic phosphate as a reactant rather than phosphate/phosphoryl attached to another molecule?

Production of fructose 1,6-bisphosphate

Production of Glucose 6-phosphate

Production of Pyruvate

Production of 1,3-bisphosphoglycerate

Production of 3-phosphoglycerate

Production of 1,3-bisphosphoglycerate

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Which is NOT a function of reactions of the Pentose Phosphate Pathway in the cell?

Facilitate photosynthesis

Conversion of a six-carbon sugar to a three-carbon sugar to produce ATP and NADH

Facilitates the reductive synthesis of fatty acids.

Helps counter oxidative damage during the transport of O2

Helps produce the sugars used to build DNA and RNA

Conversion of a six-carbon sugar to a three-carbon sugar to produce ATP and NADH

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In animals, an enzyme UNIQUE to gluconeogenesis is:

Fructose-1,6 bisphosphatase

Glyceraldehyde 3-phosphate dehydrogenase

Enolase

Phosphoglyceromutase

Aldolase

Fructose-1,6 bisphosphatase

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An enzyme used NEITHER in glycolysis NOR in gluconeogenesis is:

glucose 6-phosphatase.

pyruvate kinase.

phosphoglycerate kinase.

Phosphoglucomutase

hexokinase.

Phosphoglucomutase

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It is critical to regenerate reaction intermediates in metabolic pathways for them to continue. In anaerobic conditions, what is the product when pyruvate is reduced to regenerate NAD+ in one form of fermentation?

Lactate

Glycogen

Glucose

ATP

NADH

Lactate

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When lactic acid accumulates in muscles it is gradually carried away by the blood to the liver. What effect does lactic acid have on the respiratory rate?

It decreases the respiratory rate

Respiratory rate will initially decrease and the rapidly level off

It has no effect on the respiratory rate

It increases the respiratory rate

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Based on the last reaction of glycolysis, what can be said about the hydrolysis of PEP versus ATP

Hydrolysis of ATP is more spontaneous than hydrolysis of PEP

The rate of PEP hydrolysis is greater than the rate of ATP hydrolysis

The rate of ATP hydrolysis is greater than the rate of PEP hydrolysis

Free energy of hydrolysis is equal for PEP and ATP

Hydrolysis of PEP is more spontaneous than hydrolysis of ATP

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The 1st and 3rd reactions of glycolysis are phosphoryl group transfers from ATP. What ion is also required for this reaction?

Mg2+

PO4 3-

Mn2+

H+

Ca2+

Mg2+

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How is wasteful hydrolysis of a high-energy bond by hexokinase prevented?

Glucose doesn’t bind enzyme if enzyme is not already bound to ATP

Glucose doesn’t bind the enzyme during normal catalysis

ATP doesn’t bind enzyme if enzyme is not already bound to glucose

ATP doesn’t bind the enzyme during normal catalysis

Water cannot enter the active site of hexokinase

ATP doesn’t bind enzyme if enzyme is not already bound to glucose

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How many net NADH molecules are produced from one glucose molecule in glycolysis?

None, no net NADH is made

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Which of the following is a metabolic response to low blood glucose levels?

increased levels of insulin in blood

Increased Glucagon levels

Increased glycogen synthesis

Increased glycolysis

Decreased glycogen phosphorylase activity

Increased Glucagon levels

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Under anaerobic conditions mammals utilize a process termed the "Cori Cycle" in which glucose is fermented to lactic acid in the muscle, and lactic acid is transported to the liver where it is converted back to glucose. During these processes, the net gain/loss of other metabolites is: +2 ATP in muscle, -6 ATP in liver +32 ATP in muscle +2 ATP and +1 NADH in muscle, -6 ATP in liver and -1 NADH in liver +2 ATP in muscle, -4 ATP in liver +2 ATP and +1 NADH in muscle, -4 ATP in liver and -1 NADH in liver

+2 ATP in muscle, -6 ATP in liver

Which of the following molecules is a potent regulator of both Glycolysis and Gluconeogenesis? NAD+ Glucose Fructose 1,6-bisphosphate Pyruvate Fructose 2,6-bisphosphate

Fructose 2,6-bisphosphate

What is FALSE given what we know about the thermodynamics of the Fructose 1,6 bisPhosphatase reaction? It is an irreversible step that doesn’t need coupling to another highly irreversible step ATP has a higher phosphoryl group transfer potential than fructose 1,6 bisP It is an example of a hydrolysis reaction Pi is a product of the reaction ATP has a lower phosphoryl group transfer potential than fructose 1,6 bisP

ATP has a lower phosphoryl group transfer potential than fructose 1,6 bisP

Which of the following enzymes is not bypassed in gluconeogenesis? Enolase Hexokinase Pyruvate Kinase Phosphofructokinase 1

Enolase

What general reaction type catalyzes the transfers a functional group from one position to another position on the same molecule? Aldolases Enolases Dehydrogenases Catalases Mutases

Mutases

What enzyme catalyzes glycogen breakdown to glucose? Glycogen phosphorylase Glycogen phosphatase Transglycolase Glucose phosphatase Glycogen kinase

Glycogen phosphorylase

Conversion of pyruvate to phosphoenolpyruvate requires an important cofactor that will come up often in the rest of the course. Which one of the following is that cofactor, a carrier of CO2? Pyrophosphate (PPi) Niacin Magnesium Biotin Thiamine

Biotin

Which of the following is TRUE about aerobic glycolysis? There is a net production of one NAD+ in this pathway There is a net oxidation of glucose It is the pathway used by yeast to produce ethanol The carbons in pyruvate and glucose are in the same oxidation state Pyruvate is readily converted to lactate which accumulates in the muscles

There is a net oxidation of glucose

The first reaction in glycolysis that results in the FORMATION of a compound with high phosphoryl transfer potential is catalyzed by: pyruvate kinase Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) phosphofructokinase-1. phosphoglycerate kinase Hexokinase

Glyceraldehyde 3-phosphate dehydrogenase (GAPDH)

The principle behind using PET scans (with a radiolabeled glucose analog) to diagnose cancer metastasis is the: none of the other answers are correct greater uptake of glucose by cancer cells than normal cells greater increase in glycolytic enzymes in cancer cells than normal cells formation of lactic acid in cancers due to hypoxic conditions difference in tissue-density of the tumor and the surrounding normal tissue

greater uptake of glucose by cancer cells than normal cells

Gluconeogenesis requires the conversion of pyruvate (or lactate) to phosphoenolpyruvate in a bypass reaction. In which two cellular locations CAN this conversion take place (bearing in mind there are 2 alternative paths)? Rough endoplasmic reticulum and cytosol Golgi and rough endoplasmic reticulum Plasma membrane and cytosol Mitochondria and cytosol Cytosol and Golgi

Mitochondria and cytosol

What products do you expect from a mixture of a 6-carbon and a 4-carbon-containing sugar-phosphate substrate in the presence of a transaldolase enzyme? 8 and 2 carbon containing sugar phosphate Only one 10 carbon containing sugar phosphate 5 and 5 carbon containing sugar phosphate 7 and 3 carbon containing sugar phosphates 9 and 1 carbon containing sugar phosphates

7 and 3 carbon containing sugar phosphates

An enzyme that uses two PENTOSES as substrates to produce a HEPTOSE and a TRIOSE is a Aldolase Triose phosphate isomerase Transaldolase Transketolase Kinase

Transketolase

Identify an important enzymes that function in anaerobic fermentation in yeast. Glucose 6-phosphatase Pyruvate decarboxylase Alcohol carboxylase Coenzyme A Lactate dehydrogenase

Pyruvate decarboxylase

The oxaloacetate-to-malate-to-oxaloacetate chain of reactions of gluconeogenesis is important because this is the only way lactate can be used to synthesize glucose. It couples with a highly irreversible step to make the overall pathway irreversible this chain-of-reactions is the only way in which gluconeogenesis can occur It allows the apparent transfer of NADH from the mitochondria to cytosol It allows stimulation of glycolysis and gluconeogenesis at the same time.

It allows the apparent transfer of NADH from the mitochondria to cytosol

How many of the intermediates of glycolysis is/are phosphorylated? All of them 2 9 4 5

Which statement is FALSE regarding the reciprocal regulation of glycolysis and gluconeogenesis? The regulation of the committed step of glycolysis is a major part of reciprocal regulation Fructose 2,6 bisP is remarkable as it not only stimulates PFK-1 but it simultaneously stimulates FBPase-1 The enzyme responsible for synthesizing a regulator of reciprocal regulation contains not only the activity to make the regulator but also the activity to consume/degrade the regulator The cell doesn’t want to simultaneously activate both glycolysis and gluconeogenesis AMP can regulate both glycolysis and gluconeogenesis

Fructose 2,6 bisP is remarkable as it not only stimulates PFK-1 but it simultaneously stimulates FBPase-1

In which organisms does GLYCOLYSIS occur? Only in heterotrophs and not in autotrophs Aerobic organisms only Anaerobic organisms only Only in autotrophs and not in heterotrophs Both aerobic and anaerobic organisms

Both aerobic and anaerobic organisms

What product of ethanol fermentation is also an important reactant in Glycolysis? NAD+ Inorganic phosphate Glucose ATP Glyceraldehyde 3-phosphate

NAD+

What is false about the Pentose Phosphate Pathway? It is an irreversible pathway It generates important cellular precursors It is employed in rapidly dividing cells It has two phases, an oxidative phase and a reductive phase It is important for helping maintain the redox status of the cellular environmen

It has two phases, an oxidative phase and a reductive phase

What is one of the two products formed during Pyruvate fermentation by yeast? Acetyl-CoA Glucose Carbon dioxide NADH Lactate

Carbon dioxide

An enzyme involved in glycogen breakdown is glycogen phosphorylase. transketolase glycogen synthase. Glycogenin branching enzyme

glycogen phosphorylase.

Which one of these will NOT help in making the free energy change for a cellular process become more negative? Accumulation of reactant A decrease in the mass action ratio Depletion of product Accumulation of product

Accumulation of product

How many electrons and protons are transferred to NAD+ during a Dehydrogenation reaction in Biochemical pathways? 1 e- and 1 H+ 2 e- and 2 H+ 1 e- and 2 H+ 4 e- and 4H+ 2 e- and 1 H+

2 e- and 1 H+

Which of the following is a good indicator of large changes in the net rate of a metabolic pathway caused by small changes in specific substrate and product concentrations of a specific reaction of that pathway? Compare ΔG’o for the steady state and the accelerated or inhibited reactions Compare Vmax of the steady state to the Vmax for the accelerated or inhibited reactions Compare the Vo for the steady state to the Vo for the accelerated or inhibited reactions Compare the Turnover number to the Catalytic Efficiencies Compare the Mass Action Ratio to K’eq for the reaction

Compare the Mass Action Ratio to K’eq for the reaction

Which molecule has the highest oxidation state? Carbon dioxide (CO2) Formaldehyde (CH2O) Carbon monoxide (CO) Methane (CH4) Acetaldehyde (CH3COH)

Carbon dioxide (CO2)

Which of the following is NOT one of the 3 possible catabolic fates of Pyruvate that is formed in Glycolysis, as directly described in our text and others. Fermentation to lactate Complete oxidation to carbon dioxide and water through the Kreb’s Cycle Oxidation to ribose 5-phosphate in the Pentose Phosphate Pathway Fermentation to ethanol

Oxidation to ribose 5-phosphate in the Pentose Phosphate Pathway

Which of the following is not one of the three important groups that are donated by (transferred from) ATP under nucleophilic attack in metabolic reactions? Cyclic monophosphoryl Adenylyl Phosphoryl Pyrophosphoryl

Cyclic monophosphoryl

Select the TRUE statement In a redox reaction, there is a transfer of electrons from one molecule/ion to another. Reduction of a compound involves removal of electrons from it. Dehydrogenase enzymes remove both two e- and two hydride ions from the same molecule. In fermentation, pyruvate is oxidized to lactate. Oxidation of a compound involves addition of electrons to it.

In a redox reaction, there is a transfer of electrons from one molecule/ion to another.

Phosphofructokinase is tightly regulated in glycolysis by allosteric modulators. Which of the following is NOT an allosteric modulator of PFK-1? AMP Fructose 2,6-bisphosphate ATP Glucose ADP

Glucose

Which of the following is NOT one of the important metabolic “Fates” of pyruvate that is formed by glycolysis? CO2 Lactate Ethanol NADH Dihydroxyacetaone phosphate

Dihydroxyacetaone phosphate

Which statement is FALSE regarding the reciprocal regulation of glycolysis and gluconeogenesis? The enzyme responsible for synthesizing a regulator of reciprocal regulation contains not only the activity to make the regulator but also the activity to consume/degrade the regulator The regulation of the committed step of glycolysis is a major part of reciprocal regulation The cell doesn’t want to simultaneously activate both glycolysis and gluconeogenesis Fructose 2,6 bisP is remarkable as it not only stimulates PFK-1 but it simultaneously stimulates FBPase-1 AMP can regulate both glycolysis and gluconeogenesis

Fructose 2,6 bisP is remarkable as it not only stimulates PFK-1 but it simultaneously stimulates FBPase-1

It is uncommon for one molecule to act as both an activator and inhibitor in metabolism. Which of the following molecules both activates glycolysis and inhibits gluconeogenesis? Glucose 6-phosphate Pyruvate Fructose 2,6-bisphosphate NAD+ ADP

Fructose 2,6-bisphosphate

Which of the following is a feedback inhibitor of phosphofructokinase-1? ATP Glyceraldehyde-3-phosphate Pyruvate NADH 3-phosphoglycerat

ATP

Under which scenario will the rate of gluconeogenesis in the liver be much GREATER than that of glycolysis? Low pyruvate concentration in muscle cells increased blood sugar Low ATP/AMP ratio in the muscle cells High level of AMP in muscle cells Starvation

Starvation

Which statement about free glucose storage is FALSE? If all glucose were available as free glucose (not glycogen) the concentration gradient of intra- and extracellular glucose would be prohibitively large. The free energy difference between intra- and extracellular free glucose would be difficult to overcome for glucose uptake by the cell. Glucose is insoluble and cannot contribute to the osmotic balance of the cell. All statements are true

Glucose is insoluble and cannot contribute to the osmotic balance of the cell.

When K’eq is ________ delta G’o is _______. Greater than 1, negative Less than 1, negative 0, Positive 0, negative Greater than 1, positive

Greater than 1, negative

Sucrose and mannose both can enter Glycolysis through Feeder Pathways at what intermediate? Glucose 6-phosphate 3-phosphoglycerate Fructose 1,6-bisphosphate Glucose 1-phosphate Fructose 6-phosphate

Fructose 6-phosphate

Under low levels of glucose in the blood, the liver decreases its glycolytic rate and instead elevates the rate of aerobic respiration gluconeogenesis glycogen synthesis inhibition of glycogen phosphorylase anaerobic respiration

gluconeogenesis

Which one would be an example of a highly spontaneous reaction? Change in free energy is 0 kJ/mol Change in free energy is -2 kJ/mol Change in free energy is +20 kJ/mol Change in free energy is -20 kJ/mol Change in free energy is +2 kJ/mol

Change in free energy is -20 kJ/mol

What is a chemical rationale for the release of a CO2 molecule during the oxidative phase of the Pentose Phosphate Pathway? Reduction of pyruvate to ethanol results in release of CO2 Reduction of pyruvate to acetaldehyde results in release of CO2 Oxidation of CO by atmospheric oxygen produces CO2 Lipids and ribose 5-phosphates are reduced so that glucose can be oxidized to CO2 Beta keto acids formed upon oxidation decarboxylate spontaneously

Beta keto acids formed upon oxidation decarboxylate spontaneously

What part of UTP is transferred to glucose 1P to form glucose-UDP for glycogen synthesis? Phosphoryl group UTP Uracil Uridylyl (UMP) group UDP

Uridylyl (UMP) group

The enzyme that catalyzes the branching of glycogen polymers catalyzes Breakage of (α1 → 6) bonds Synthesis of (α1 → 6) bonds Synthesis of (α1 → 4) bonds Synthesis of (beta1 → 4) bonds Breakage of (beta1 → 4) bonds

Synthesis of (α1 → 6) bonds

Which cofactor, or more properly prosthetic group, can perform as a one-electron or a two-electron carrier? NADPH Coenzyme A Magnesium FAD NADH

FAD

Which one is not a defining feature of a committed step of a pathway? It is the only irreversible reaction in the pathway The reaction has a free energy change in the cell that is negative It is a highly regulated step in the pathway It must be a spontaneous reaction under the conditions of the cell Most feed-in metabolites enter the pathway before this step

It is the only irreversible reaction in the pathway

The change in free energy (ΔG’o) for the above reaction is -16.7 kJ/mol. The reaction that comes next in glycolysis has a free energy change of 1.7 kJ/mol. The pH of these reactions is optimal near 7.4. What is the overall free energy change for these reactions? -15 kJ/mol. -18.4 kJ/mol 15 kJ/mol -28.4 kJ/mol 18.4 kJ/mol

-15 kJ/mol.

Glucose residues are removed from glycogen until a branch in the polysaccharide is reached. What specifically happens at the branch to permit more catabolism? More glucose residues are removed at branches by the same glycosidases that remove non-branched glucose since the enzyme is multifunctional Nothing happens since we cannot break any branches “Debranching Enzyme” breaks the branches The alpha-1,6-glycosidic linkage is converted to a beta-1,6-glycosidic linkage, and then a glycosidase cleaves it

“Debranching Enzyme” breaks the branches

Glycolysis produces important products for other cells than the ones making it. What is the net production of ATP and NADH from one Glucose molecule? 1, 1 1, 2 4, 2 2, 4 2,2

2,2

For the reaction A to B, DeltaG'° = –60 kJ/mol. The reaction is started with 10 mmol of A; no B is initially present. After 24 hours, analysis reveals the presence of 2 mmol of B, 8 mmol of A. Which is the most likely explanation? A and B have reached equilibrium concentrations. An enzyme has shifted the equilibrium toward A. Formation of B is thermodynamically unfavorable. B formation is kinetically slow; equilibrium has not been reached by 24 hours. The result described is impossible, given the fact that DeltaG'° is –60 kJ/mol.

B formation is kinetically slow; equilibrium has not been reached by 24 hours.

Glycogen synthase CANNOT Add glucose to the reducing end of a glycogen polymer form (alpha 1->4) linkages in a growing glycogen polymer Get phosphorylated in the cell, ever. Use a large growing glycogen polymer as a reactant Use Glucose-UDP as a building block to grow a glycogen polymer

Add glucose to the reducing end of a glycogen polymer

Pyruvate kinase transfers a phosphate group from phosphoenolpyruvate (PEP) to ADP, forming pyruvate and ATP. This reaction is essentially irreversible. Which of the following is the best explanation for the irreversible nature of this reaction? The change in free energy for the overall reaction is large and negative There is a different enzyme in the cell that synthesizes PEP Binding of pyruvate to the active site is weak relative to binding of PEP Reaction is coupled to pyruvate dehydrogenase reaction Hydrolysis of ATP is highly favorable

The change in free energy for the overall reaction is large and negative

If the standard change in free energy of the reaction is +73 kJoule/mole, what is true about this reaction at standard conditions? will occur at a very fast pace. will occur at a very slow pace. will occur spontaneously. will not occur spontaneously. More information is needed to determine if the reaction will be spontaneous or not under these conditions.

will not occur spontaneously.

Which statement is true about biochemical oxidation-reduction reactions? Dehydrogenases typically remove two electrons and two hydrides. Every oxidation must be accompanied by a reduction. During oxidation a compound gains electrons. They usually proceed through homolytic cleavage. There are two commonly accessed oxidation states of carbon.

Every oxidation must be accompanied by a reduction.

If the cell needs to replenish nucleoside triphosphates for suddenly increasing transcription, it will probably increase only the steps that increase NADPH production to reduce ribose to deoxyribose increase only the oxidative phase of the PPP increase the flux through the complete PPP cyclic pathway increase only the non-oxidative phase of the PPP

increase only the oxidative phase of the PPP

When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate. Which statement is MOST nearly correct, when applied to the reaction shown (R = 8.315 J/mol · K and T = 298 K)? glucose 6-phosphate ⇋ fructose 6-phosphate ΔG'°is incalculably large and positive. ΔG'°is zero. ΔG'° is –1.7 kJ/mol. ΔG'° is +1.7 kJ/mol. ΔG'°is incalculably large and negative.

ΔG'° is +1.7 kJ/mol.

What enzyme will be activated by the AMP, which then activates other ATP-producing pathways? Pyruvate kinase Phosphofructokinase-1 Hexokinase IV cAMP-dependent protein kinase AMP-dependent protein kinase

AMP-dependent protein kinase

Which of the following is also a high-energy bond that carries a lot of potential energy, making it relatively common in metabolism. Biphosphate of NADH Coenzyme A Bisphosphates on phosphoinositides Thioester 3’5’-phosphate linkage of cAMP

Thioester

Which of the following is a metabolic response to high blood glucose levels? Increased glycogen phosphorylase activity Decreased glycolysis Increased levels of insulin in blood Decreased glycogen synthesis Increased Glucagon levels

Increased levels of insulin in blood

For the reaction, ΔG'° = +29.7 kJ/mol L-malate + NAD+ → oxaloacetate + NADH + H+ The reaction as written: may occur in cells at some concentrations of substrate and product. can occur only in a cell in which NADH is converted to NAD+ by electron transport. can never occur in a cell. can occur in a cell only if it is directly coupled to another reaction for which ΔG'° is negative. cannot occur because of its large activation energy.

may occur in cells at some concentrations of substrate and product.

What term best characterizes the following: ADP + GTP → ATP + GDP Phosphorylation Adenylylation Prenylation Autophosphorylation Transphosphorylation

Transphosphorylation

What enzyme then removes glucose from glycogen in a phosphorolysis reaction? Glycogen kinase Inorganic pyrophosphatase Glycogen phosphorylase Glycogenin Glycogen synthase

Glycogen phosphorylase

What important reaction occurred to yield α-ketoglutarate from isocitrate Substrate level phosphorylation and hydration Decarboxylation and reduction of NAD+ Decarboxylation and hydration Decarboxylation and oxidation of NADH

Decarboxylation and reduction of NAD+

What Product of the Glyoxylate Cycle is a Reactant of the Citric Acid Cycle? Aspartate Succinate Alpha-ketoglutarate Aconitate Glyoxylate

Succinate

The conversion of 1 mol of glucose to 6 mol of CO2 via glycolysis and the citric acid cycle also yields _____ mol of NADH, _____ mol of FADH2, and _____ mol of ATP/GTP (total). 5, 1, 2 3, 1, 1 0, 0, 32 4, 1, 1 10; 2; 4

10; 2; 4

Which of the following molecules is NOT associated with Ketone Bodies? Acetoacetate Beta-hydroxybutyrate Acetyl-CoA Acetone

Acetyl-CoA

Acyl-CoA dehydrogenase passes electrons to the Electron Transferring Flavoprotein (ETF). What molecule is the immediate source of these electrons? That is, what molecule in ETF and acts as the last electron donor before the electron transport chain? NADH Fatty acyl-CoA Acetyl CoA FAD Malonyl-CoA

FAD

What enzyme catalyzes an isomerization reaction in the Citric Acid Cycle? triose phosphate isomerase citrate synthase phosphoglycerate mutase Succinyl CoA synthetase Aconitase

Aconitase

Full oxidation of a polyunsaturated fatty acid (18:2) gives rise to a product NOT given out by full oxidation of a monounsaturated fatty acid (18:1). This product is most likely: water NADP+ NADH Acetyl-CoA FADH2

NADP+

What reaction uses Pi as a substrate? Reaction catalyzed by: Glucose 6P dehydrogenase Citrate synthase Phosphofructokinase-1 Glyceraldehyde 3-phosphate dehydrogenase Pyruvate carboxylase

Glyceraldehyde 3-phosphate dehydrogenase

What two chemical mechanisms change pyruvate to acetyl-CoA in the pyruvate dehydrogenase complex? Condensation and oxidation Dehydrogenation and decarboxylation Dehydrogenation and oxidation Decarboxylation and condensation Condensation and dehydrogenation

Dehydrogenation and decarboxylation

Triglycerides and lipoproteins associate into what structure which is a vascular carrier of these lipids? Glyoxysomes Mitochondria Bile salts Chylomicrons Peroxisomes

Chylomicrons

Of the reactions that produce alpha-ketoglutarate and succinyl-CoA, both use what reaction mechanism? Phosphorylation Oxidative decarboxylation Hydration Dehydration Dehydrogenation

Oxidative decarboxylation

Which of the following does not serve as a coenzymes or prosthetic group for the Pyruvate Dehydrogenase Complex? Coenzyme A Lipoate Thiamine pyrophosphate Flavin adenine nucleotide Biotin

Biotin

The conversion of 1 mol of pyruvate to 3 mol of CO2 via pyruvate dehydrogenase and the citric acid cycle also yields _____ mol of NADH, _____ mol of FADH2, and _____ mol of ATP/GTP (total). 4; 1; 1 2; 2; 2 3; 2; 0 4; 2; 1 3; 1; 1

4; 1; 1

Acyl chains with odd numbers of carbons can undergo oxidation, yielding which of the following as a final product molecule? β-hydroxybutyrate Propionyl-CoA Acetyl CoA Palmitate Acetone

Propionyl-CoA

Which of the following is not a component of Chylomicrons? Phospholipids Apolipoproteins Triacylglycerols Cholesterol Bile Salts

Bile Salts

Which one is used to partly digest ingested fats in the adipose tissues in response to low blood sugar? Intestinal lipase Hormone sensitive lipase Lipoprotein lipase HGM-CoA lyase All the answers can perform this function

Hormone-sensitive lipase

What combination of step and enzyme accurately depict a reaction in fatty acyl-CoA beta oxidation that uses a prosthetic group for catalyzing a redox reaction? Step 1 – beta-hydroxyacyl-CoA dehydrogenase Step 3 – beta-hydroxyacyl-CoA dehydrogenase Step 1 – acyl-CoA dehydrogenase Step 3 - acyl-CoA dehydrogenase None of the combinations are correct

Step 1 – acyl-CoA dehydrogenase

What is the direct role of NAD+ in the pyruvate dehydrogenase complex reaction cascade? It oxidizes FADH2 It reduces FADH2 It reduces lipoate It reduces TPP It oxidizes TPP

It oxidizes FADH2

Pools of which of the following enzyme(s) are found in both the mitochondrial matrix and the cytosol: Succinate dehydrogenase All of these None of these Lactate dehydrogenase Malate dehydrogenase

Malate dehydrogenase

Aconitase has an unusual chemical feature associated with 3 Cys residues. What is that feature? Binding site for a competitive inhibitor Iron-sulfur center Disulfide linkage Heme group Cytochrome

Iron-sulfur center

What is the common feature of these three reactions: isocitrate dehydrogenase, pyruvate dehydrogenase complex, and alpha-ketoglutarate dehydrogenase complex? All three are highly endergonic All three require prosthetic groups All three produce CoA-SH All three require NADH All three produce CO2

All three produce CO2

Which of the following enzymes is not involved in a decarboxylation reaction? All of the above are involved in decarboxylation reactions Isocitrate dehydrogenase Alpha-ketoglutarate dehydrogenase Pyruvate dehydrogenase Malate dehydrogenase

Malate dehydrogenase

What class of lipids is the primary target of beta-oxidation? Triglycerides Phospholipids Sphingolipids Glycerols Glycerophospholipids

Triglycerides

Which one of these fatty acids when oxidized would give rise to propionyl-CoA as a product? (18:3) (16:2) (20:1) (22:0) (17:0)

(17:0)

High cellular concentrations of what molecule would INHIBIT the entry of pyruvate via acetyl CoA into the citric acid cycle? NADH AMP Calcium (Ca2+) Coenzyme A oxaloacetate

NADH

Which of the following pathways produces Succinyl-CoA for the Kreb’s Cycle? Oxidation of polyunsaturated fatty acids Beta-oxidation of fatty acids with even numbers of carbons Oxidation of phospholipids Beta-oxidation of fatty acids with odd numbers of carbons Oxidation of monounsaturated fatty acids

Beta-oxidation of fatty acids with odd numbers of carbons

When a fatty acid of chemical formula 22:1 Δ9 is oxidized using the beta-oxidation pathway, the number of FADH2 produced will be: 9 8 11 22 10

How is a specific reaction in the Citric Acid Cycle that uses an achiral substrate able to form only one enantiomeric form of a chiral product? The energy of ATP hydrolysis drives chiral center formation. Only one enantiomer of the substrate can fit in the active site All enzymes, their active sites, and their complexes with the transition state of a reaction are chiral. Substrate-level phosphorylation. Water can be chiral at 55.5 M concentration

All enzymes, their active sites, and their complexes with the transition state of a reaction are chiral.

A coenzyme/cosubstrate required for formation of an acyl-CoA and an acetyl-CoA from beta-ketoacyl-CoA during beta oxidation CoA-SH NAD+ FAD All other answers are correct. H2O

CoA-SH

What additional reactant is required for oxidation of polyunsaturated fatty acids compared with saturated fatty acids? NAD+ ATP FAD NAD(P)H Acetyl-CoA

NAD(P)H

Which one of the following enzymatic activities would be decreased by the decreased uptake of thiamine by chronic alcohol users? alpha-Ketoglutarate dehydrogenase complex Malate dehydrogenase Isocitrate dehydrogenase Succinate dehydrogenase Fumarase

alpha-Ketoglutarate dehydrogenase complex

If the FREE FATTY ACID (16:1) is catabolized completely, to carbon dioxide and water, the NET yield of ATP (i.e., ATP potential from NTP, NADH, and FADH2) per molecule of FREE FATTY ACID is _____ ATP. 108 106.5 106 104.5 112

104.5

What the two additional reaction mechanisms are performed on the unsaturated fatty acid, Linoleic acid (18:3) in the correct order, to permit its entry into beta-oxidation? Isomerization, Reduction Oxidation, reduction Reduction, Isomerization Oxidation, hydration Isomerization, Oxidation

Isomerization, Reduction

What class of proteins is associated with chylomicrons and functions to target lipids for delivery to specific tissues? Apolipoproteins Carnitines Perilipins Serum albumin Phospholipases

Apolipoproteins

Which of the following important reactants is NOT produced by the first 5 steps of the Kreb’s Cycle? Succinate All of the above are produced by the first 5 steps CO2 GTP NADH

All of the above are produced by the first 5 steps

Malonate is a competitive inhibitor of succinate dehydrogenase. If malonate is added to a mitochondrial preparation that is oxidizing pyruvate as a substrate, which of the following compounds would you expect to immediately decrease in concentration? Isocitrate Succinate Pyruvate Citrate Fumarate

Fumarate

How many acetyl-CoA molecules are obtained from linoleic acid [18:2 (Δ 9,12)] via beta-oxidation? 7 The number cannot be determined with the given information 18 9 16

Where does ketogenesis occur in primates such as humans? adipose tissue skeletal muscle the brain the liver both the liver and adipose tissue

the liver

Which one of the following is not occurring in the Citric Acid Cycle? Substrate-level phosphorylation FADH2 formation Oxidative decarboxylation C-C bond formation reaction Acetyl CoA formation

Acetyl CoA formation

What valuable Citric Acid Cycle intermediate is made by PEP carboxykinase and by PEP carboxylase, a molecule that is usually in low concentration in cells? Oxaloacetate Fumarate Pyruvate Citrate Malate

Oxaloacetate

Which one of the following is not part of the Citric acid cycle? Oxidation of pyruvate Formation of a C-C bond Synthesis of NTP Use of FAD+ as a substrate Simultaneous oxidation and loss of CO2

Oxidation of pyruvate

What molecule serves as an example of how an intermediate on one energy-generating metabolic pathway can regulate the flux through ANOTHER energy-generating metabolic pathway? Mg2+ Fructose 1,6 bisP ATP Citrate O2

Citrate

The reaction in the beta-oxidation of fatty acids that is most similar to the reaction catalyzed by fumarase in the citric acid cycle is catalyzed by: acyl CoA dehydrogenase enoyl CoA hydratase thiolase hormone-sensitive lipase (HSL) beta-hydroxy acyl CoA dehydrogenase

enoyl CoA hydratase

Which of the following intermediates can be used to produce Phosphoenolpyruvate that could be used in Gluconeogenesis? Malate Succinyl CoA Pyruvate Succinate Oxaloacetate

Oxaloacetate

-oxidation comprises a repeating set of 4 reactions that remove acetyl groups from acyl chains. Which reaction involves a thiolate in a cleavage reaction? None of the steps involve a thiolate group Step 1 Step 2 Step 3 Step 4

Step 4

A coenzyme/cosubstrate required for formation of a beta-ketoacyl-CoA from a beta-hydroxyacyl-CoA is FAD NAD+ CoA-SH All other answers are correct. TPP

NAD+

GTP is produced by the Kreb’s Cycle. What important enzyme can then produce ATP from the GTP if there is sufficient ADP present? Nucleoside diphosphate kinase Protein kinase A F-type ATPase Adenylate kinase Adenylate cyclase

Nucleoside diphosphate kinase

Triacyl glycerol stores energy not only in the form of fatty acids but also in the form of a product that can be metabolized to undergo Entire PPP cycle Oxidative phase of the PPP The ATP-generating steps of glycolysis Non-oxidative phase of the PPP None of the answers is correct

The ATP-generating steps of glycolysis

Plants can make glucose out of fatty acids because They encode odd-numbered fatty acids that are not found in animals They are able combine the glyoxylate cycle to the CAC in the mitochondria The rate of fatty acid oxidation is greater in plants that in animals The oxaloacetate concentrations are much higher in plants None of the other answers is true.

They are able combine the glyoxylate cycle to the CAC in the mitochondria

What is the location for ketone body biogenesis? Hepatocytes Glial cells Adipocytes Myocytes Neurons

Hepatocytes

How many ATP equivalents are required to produce an activated fatty acid in order for it to enter beta-oxidation? 1 None, because GTP is the source of energy 3 One for beta-oxidation and two for omega-oxidation 2

The redox reaction catalyzed by which of these enzymes uses a cofactor/co-enzyme/prosthetic group that is different than that of all the other ones? (In other words, all the other enzymes use the same redox cofactor/co-enzyme/prosthetic group) glucose 6-phosphate dehydrogenase malate dehydrogenase succinate dehydrogenase isocitrate dehydrogenase glyceraldehyde 3-phosphate dehydrogenase

succinate dehydrogenase

Which of the following statements is TRUE regarding the thermodynamics of the Citric Acid Cycle? The Cycle is an endergonic set of reactions The free energy input is significantly positive, but the equilibrium indicates that the Cycle will continue uninterrupted All the reactions contain free energy changes that are near 0, which is one reason why the cycle can continue uninterrupted It is an exergonic set of reactions Only the final 3 steps are significantly negative, but the sum of these three free energy changes drive the rest of the Cycle

It is an exergonic set of reactions

Which of the following would contain Glyoxysomes? Algae Gram-negative bacteria Vertebrates Yeast Leafy plants

Leafy plants

Chylomicrons are associated with lipid metabolism. What is their function? Oxidation of fatty acyl chains in plants and algae Oxidation of fatty acyl-CoA that have odd numbers of carbons Transport of triglycerides in the blood Assembly of acyl chains and glycerol into triacylglycerols Transport of fatty acyl chains from the gut lumen to the vascular space

Transport of triglycerides in the blood

Fumarate

A substrate required for formation of a beta-hydroxyacyl-CoA from trans-Δ2-enoyl-CoA is FAD H2O CoA-SH All other answers are correct. NAD+

H2O

Which reaction of the Citric Acid Cycle combines a 4-carbon and a 2-carbon intermediate to form a 6-carbon intermediate? 2 3 5 1 4

Citric Acid Cycle happens in the _____ and glycolysis happens in the _____. Plasma membrane, Cytosol Mitochondria, Cytosol Cytosol, Cytosol Cytosol, Mitochondria Cytosol, Plasma membrane

Mitochondria, Cytosol

Plants contain a lot of fatty acids with odd numbers of carbons. Oxidation of these lipids produces Propionyl-CoA. Complete oxidation of this molecule requires extra reactions that produce what Krebs Cycle intermediate as the final product? Malate Citrate Succinate Succinyl-CoA Alpha-ketoglutarate

Succinyl-CoA

All redox reactions of the citric acid cycle are linked to the reduction of nicotinamide-containing molecule EXCEPT that catalyzed by: succinate dehydrogenase. α-ketoglutarate dehydrogenase complex malate dehydrogenase. pyruvate dehydrogenase isocitrate dehydrogenase.

succinate dehydrogenase.

The three-carbon product from the hydrolysis of triacylglycerols is fed into glycolysis as: dihydroxyacetone-1,3- bisphosphate. Glyceraldehyde 3-phosphate acetyl CoA. glucose-6-phosphate. glucose.

Glyceraldehyde 3-phosphate

The isomerization of citrate to isocitrate: protects cells from the toxic effects of arsenite ion. is an oxidation reaction. converts a tertiary alcohol, which cannot easily be oxidized, to a secondary alcohol that can be oxidized. is a major regulatory step for the citric acid cycle. is the only unnecessary step of the citric acid cycle.

converts a tertiary alcohol, which cannot easily be oxidized, to a secondary alcohol that can be oxidized.

The fatty acid molecules obtained in a blood draw from a healthy individual will be found to be Bound to a protein belonging to the albumin family. Water-soluble as they are much smaller and more hydrophilic than triacylglycerol Bound to bile salt micelles. Bound to carnitine. Bound to myoglobin.

Bound to a protein belonging to the albumin family.

How many molecules of acetyl CoA are produced from a single molecule of glucose for participation in the Krebs cycle? 4 2 1 0 3

A combination of a cyclic pathway in the glyoxysome/peroxisome and a cyclic pathway in the mitochondria is used For the synthesis of fatty acids from acetyl-CoA in animals. To perform oxidative phosphorylation for gluconeogenesis in a hibernating bear For gluconeogenesis starting with fatty acids For the synthesis of fatty acids from TCA cycle intermediates.

For gluconeogenesis starting with fatty acids

One reason that fatty acids make an excellent source of fuel is that they carry more energy per carbon atom than do carbohydrates. This is because: The carbons in fatty acids are more hydrophobic than the carbons in carbohydrates. The carbons in fatty acids are lighter than carbons in carbohydrates. The carbons in fatty acids are more polar than the carbons in carbohydrates. The carbons in fatty acids are more oxidized than the carbons in carbohydrates. The carbons in fatty acids are more reduced than the carbons in carbohydrates.

The carbons in fatty acids are more reduced than the carbons in carbohydrates.

Anaplerotic reactions produce pyruvate and citrate to maintain constant levels of citric acid cycle intermediates all of the other answers are correct recycle pantothenate used to make CoA Use citric acid cycle intermediates to make other useful precursors in the cell produce citric acid cycle intermediates

produce citric acid cycle intermediates

What is the primary function of the chylomicron in absorption of fats? It helps solubilize fats so that they can be delivered from the intestinal cells to adipocytes via the blood phosphoryl group transfer It is a lipase, which is an enzyme that breaks down lipids into fatty acids It is produced in the liver and is important for gluconeogenesis it is a coenzyme required for the Citric Acid Cycle

It helps solubilize fats so that they can be delivered from the intestinal cells to adipocytes via the blood

What is the primary function of bile? It helps solubilize fats in the diet so that they can be broken down and absorbed into the body it is a coenzyme required for the Citric Acid Cycle It is produced in the liver and is important for gluconeogenesis phosphoryl group transfer It is a lipase, which is an enzyme that breaks down lipids into fatty acids

It helps solubilize fats in the diet so that they can be broken down and absorbed into the body

The reaction of the citric acid cycle that involves substrate-level phosphorylation forms the following metabolite as a product: fumarate. alphaketoglutarate succinyl CoA succinate isocitrate.

succinate

Triglycerides are carried in the blood by ______ while free fatty acids in the blood bind to and are carried by _______. Chylomicrons, Perilipins Chylomicrons, Serum albumin Perilipins, Serum albumin Perilipins, Chylomicrons Serum albumin, perilipins

Chylomicrons, Serum albumin

Exam 3 Problem Roulette Flashcards

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