Final Exam Questions

Enzyme X has a Km of 50 𝜇M and a Vmax of 100mM/s. Calculate the reaction velocity of Enzyme X at a substrate concentration of 68 𝜇M. Answer in units of mM/s and round to two decimal places.

57.63

Use the Henderson-Hasselbalch equation to calculate the ratio of HCO3- to H2CO3 (Ka = 4.2 x 10-7) in a solution with a pH of 7.40). Select the closest approximation.

9.48 x 10^-2:1

5.98 x 10^-1:1

1.67:1

1.06 x 10^1:1

1.06 x 10^1:1

Which amino acid would most likely be found on the surface of a water-soluble globular protein?

Q

A

L

F

W

Q

Ammonium sulfate is useful in salting out during protein purification because

it has a specific affinity for a single amino acid and hence can be used on an affinity column to bond only peptides containing that amino acid.

it contains nitrogen and sulfur, both of which occur in proteins.

it is sparingly soluble in water, causing proteins to co-precipitate with it.

it forms ion-dipole interactions with water, making proteins less soluble and more likely to precipitate.

it forms ion-dipole interactions with water, making proteins less soluble and more likely to precipitate.

Hb Great Lakes is a mutated form of hemoglobin that has a higher affinity for oxygen compared to adult hemoglobin (HbA). On an oxygen binding curve, where would the curve for HbA be relative to that of Hb Great Lakes?

HbA would be to the right of Hb Great Lakes.

Both binding curves would be the same.

HbA would be to the left of Hb Great Lakes.

HbA would be to the right of Hb Great Lakes.

What is the net charge of His when pH=5?

+2

-2

+1

0

-1

+1

Which of these would decrease the affinity of hemoglobin for oxygen?

increasing the partial pressure of oxygen

lowering the pH

neither of these would decrease the affinity of hemoglobin for oxygen

lowering the pH

The order of a reaction can be determined from the overall balanced equation for the reaction.

True

False

False

The active site of an enzyme

is the portion of the enzyme to which the substrate binds.

is frequently located in a cleft in the enzyme.

contains the reactive groups that catalyze the reaction.

All of these are correct.

All of these are correct.

Gel filtration purifies protein based on their_______ .

molecular weight

charge

hydrophobicity

molecular weight

The following diagram shows the anode, cathode, and pH gradient of an isoelectric focusing bed:

anode+ −cathode

pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14

If the amino acid glycine were placed in the bed where the pH is 7, and the current were turned on, it would migrate closest to which of the following positions?

pH 8

pH 10

pH 4

pH 6

pH 6

What is the conjugate acid of dimethylamine, (CH3)2NH?

CH3CH2NH─

(CH3)2NH2+

(CH3)2N─

CH3CH2NH+

(CH3)2NH2─

(CH3)2N+

(CH3)2NH2+

You have the following polypeptide:

CVMDL

Each of the answer choices includes a substitution in the amino acid sequence. Which of the substitutions would be most likely to result in disruptions to the tertiary structure of the amino acid? The substitution in each is bolded to help you more easily view the changes.

SVMDL

CVMDI

CVMDA

CVMEL

CQMDL

CQMDL

Carbon monoxide is a dangerous gas. Why?

None of these answers are correct.

Carbon monoxide binds strongly to all heme groups, not allowing any oxygen to bind.

Once carbon monoxide binds to one heme group, it dramatically weakens the binding of oxygen to other heme groups. This results in hemoglobin being unable to release oxygen to tissues due to it releasing prematurely in the lungs.

Once carbon monoxide binds to one heme group, any oxygens that bind to the other heme groups are bound much more tightly. This results in hemoglobin being unable to release oxygen to tissues.

Once carbon monoxide binds to one heme group, any oxygens that bind to the other heme groups are bound much more tightly. This results in hemoglobin being unable to release oxygen to tissues.

On a Lineweaver-Burk plot, what does the Y-intercept represent?

-1/KM

kcat/KM

1/Vmax

KM/Vmax

1/Vmax

In an alpha helical structure, hydrogen bonding occurs

parallel to the helical axis.

pointing inside of the helix.

perpendicular to the helical axis.

among the side chains of the amino acids.

parallel to the helical axis.

What is the pI of Gly?

9.60

7.26

2.34

11.94

5.97

5.97

Enzyme A has a Km of 5.0mM and a Vmax of 10.0mM/s. Enzyme B has a Km of 1.0mM and Vmax of 5mM/s. Assuming that you are at a substrate concentration in which your velocity is still much less than Vmax for either of these enzymes AND both enzymes are equal in concentration, which of the enzymes would be considered more efficient?

Enzyme B

No answer text provided.

Enzyme A

These enzymes have the same efficiency.

Enzyme B

Which enzyme class is characterized by its ability to catalyze reactions that exchange functional groups between molecules?

Oxidoreductase

Isomerase

Transferase

Hydrolase

Lyase

Ligase

Transferase

In a solution of room temperature water, [H+] = 7.6*10^-8M. What is the pH of this solution?

7.12

8.31

7.60

6.88

7.12

What amino acid performs the nucleophilic attack in the chymotrypsin mechanism?

His

Ser

Asp

Lys

Ser

An enzyme-catalyzed reaction is inhibited by a competitive inhibitor. What is the most probable effect exerted by this inhibitor on the reaction?

Lowered Km and increased Vmax.

Lowered Km and decreased Vmax.

Lowered Km and no change in Vmax.

Increased Km and decreased Vmax.

Increased Km and no change in Vmax.

Increased Km and increased Vmax.

Increased Km and no change in Vmax.

In hemoglobin, the ________ directly binds to iron and helps anchor the heme in the globin.

Propionate group of heme

Proximal histidine

Distal histidine

Hydrophobic end of heme

Proximal histidine

A sample of peptide of unknown sequence was treated with trypsin to produce the following smaller peptides:

1) Asn-Thr-Trp-Met-Ile-Lys        2) Gly-Tyr-Met-Gln-Phe       3) Val-Leu-Gly-Met-Ser-Arg

Another sample of the same peptide was treated with cyanogen bromide and gave the following smaller peptides:

1) Gln-Phe       2) Val-Leu-Gly-Met     3) Ile-Lys-Gly-Tyr-Met    4) Ser-Arg-Asn-Thr-Trp-Met

What is the sequence of the original peptide?

I-K-G-Y-M-Q-F-S-R-N-T-W-M-V-L-G-M

N-T-W-M-I-K-G-Y-M-Q-F-V-L-G-M-S-R

Q-F-V-L-G-M-S-R-N-T-W-M-I-K-G-Y-M

V-L-G-M-S-R-N-T-W-M-I-K-G-Y-M-Q-F

V-L-G-M-S-R-N-T-W-M-I-K-G-Y-M-Q-F

What is the net charge of the following peptide chain at pH = 10?

SPARKS

0

-1

+1

+2

+3

+1

All catalysts work by ___ the ___ for a reaction

decreasing, activation energy

Enzyme X has a Km of 40 𝜇M. What percentage of Enzyme X’s maximum velocity will be achieved at a substrate concentration of 32 𝜇M? Round to two decimal places. Your answer should be between 0 and 100.

44

Which of the following is a property that may be expected of a globular protein?

Compact structure held together by several different IMFs

Intrinsic folding of peptide backbone to form a spherical shape

Water-soluble

All of these are properties of a globular protein.

All of these are properties of a globular protein.

Determine the catalytic efficiency of an enzyme with the following kinetics data: kcat = 422s-1, KM = 0.5nM. Answer in units of mM-1s-1.

8.44*10^14

844

211

211*10^-9

8.44*10^8

You are in a lab studying an enzyme with multiple subunits. At one point during the experiment, you decide to take a closer look at some of your enzymes. Upon close inspection, you observe that your enzyme molecules either have all of their active sites in a T conformation or have all of their active sites in an R conformation. This is most specifically explained by which model of enzyme behavior? 

Michaelis-Menten

Concerted Allosteric

Sequential Allosteric

Lineweaver-Burke

Concerted Allosteric

You disrupt all of the hydrogen bonds in a protein. Which of the following structure(s) would least likely be affected?

All of the above would be equally affected

Quaternary structure

Tertiary structure

Secondary structure

Primary structure

Primary structure

Which substance would you expect to be eluted first from a molecular sieve (size exclusion) column?

myoglobin

both would bond strongly to the column and not elute.

hemoglobin

hemoglobin

A decrease in pH causes more hemoglobin to shift to the

pH does not affect the balance between oxygenated and deoxygenated hemoglobin.

Deoxygenated form

Oxygenated form

Deoxygenated form

Which of these amino acids would be considered a nonpolar amino acid?

Asp

Asn

Gln

Gly

Glu

Gly

In electrophoresis experiments

the polarity of substances to be separated is more important than their charge or size.

an electric field must be applied to the mixture to be separated.

the sample can be badly degraded as a result of the separation.

the separation must be carried out in bright light.

an electric field must be applied to the mixture to be separated.

Which of the following amino acid side chains is most likely to participate in acid-base catalysis?

Met

Leu

Ala

His

His

What is the pI of Lys?

5.565

6.355

10.530

9.740

9.740

Protein synthesis takes place in

nucleolus

golgi apparatus

ribosomes

smooth endoplasmic reticulum

none of the above

ribosomes

Which of the following are NOT a step in the chymotrypsin mechanism? Note: the term 'scissile bond' is referring to the bond that chymotrypsin cleaves.

The nitrogen of histidine performing a nucleophilic attack on the nitrogen of the scissile bond.

His accepting a proton from water to form a hydroxide ion.

The oxygen of Ser performing a nucleophilic attack on a carbonyl carbon.

Ser donating a proton to His to form an alkoxide ion

The nitrogen of histidine performing a nucleophilic attack on the nitrogen of the scissile bond.

Calculate the K_d of myoglobin if it was 57% saturated at a [O₂] of 7.0M. Estimate to the nearest whole number.

5

You have the following polypeptide:

           GVLTA

Each of the answer choices includes a substitution in the amino acid sequence.  Which of the substitutions would be most likely to result in disruptions to the tertiary structure of the amino acid?  The substitution in each is bolded to help you more easily view the changes.

GGLTA

GVLRA

GVLSA

AVLTA

GVLRA

A buffer solution at pH 10 has a ratio of [HA]/[A⁻] of 10. What is the pK_a of the acid?

12

8

9

11

10

11

Which of the following molecules contains at least one polar bond but is overall a nonpolar molecule?

None of these

H₂O

CH₃Cl

CCl₄

CH₄

CCl₄

A membrane protein that allows ions to spontaneously flow across the lipid bilayer in the form of a channel would most likely be classified as:

peripheral 

integral 

neither of these

integral 

A furanose is a sugar that

is always a five-carbon open-chain sugar.

is always a six-carbon open-chain sugar.

contains a six-membered ring as part of its cyclic structure.

contains a five-membered ring as part of its cyclic structure.

contains a five-membered ring as part of its cyclic structure.

Order a generic signaling pathway from beginning to end. Full credit is only given for exact matches. 

Conformational change in intracellular portion of receptor. 
Binding of primary messenger to extracellular receptor.

Activation of enzyme that produces secondary messenger.

Activation of effector protein kinases. 

Binding of primary messenger to extracellular receptor.

Conformational change in intracellular portion of receptor. 

Activation of enzyme that produces secondary messenger.

Activation of effector protein kinases. 

Which statement is true?

Channels are not specific and allow any molecule to move through.

Channels are incapable of becoming saturated and therefore can transport molecules at a speed up to the diffusion limit.

Channels are capable of allowing for non-favorable movement against a concentration gradient.

Channels are incapable of becoming saturated and therefore can transport molecules at a speed up to the diffusion limit.

How many enzymes of glycolysis are control points for the pathway?

2

4

3

1

All the enzymes serve as control points.

3

Which of the following is not a characteristic of most fatty acids?

When fatty acids associate, they do so in a micelle formation.

All of these characterize fatty acids.

They most often contain trans double bonds.

The hydrocarbon portion can be saturated or unsaturated.

They include a single carboxyl (−COOH) group

They most often contain trans double bonds.

Lipases are responsible for breaking down:

Lipids

Nucleic Acids

Polysaccharides

Polypeptides

Lipids

Asparagine can provide the nitrogen for N-linkages through its R group.

True

False

True

The cholera toxin causes severe dehydration due to an excess of ions leaving intestinal cells and entering the intestinal tract, which leads to excessive water expulsion in the form of waste. The ion channels in intestinal cells are controlled by a signaling pathway that utilizes a G-protein; when this signal is active, ion channels are open to allow movement of ions out of the cell. What is a possible way the cholera toxin affects this signaling pathway?

It activates a phosphatase that will remove a phosphate from GTP molecules in the cytosol.

It binds to the G-protein and causes it to irreversibly bind GTP while also inhibiting GTPase activity.

It degrades the primary messenger that normally activates the signal to open the ion channels.

All of these are possible mechanisms of the cholera toxin.

It binds to the G-protein and causes it to irreversibly bind GTP while also inhibiting GTPase activity.

Which of the following is at a higher level of oxidation than CH₃CHO?

CH₃CO₂H

CH₂=CH₂

none of the above

CH₃CH₂OH

CH₃CH₃

CH₃CO₂H

For a cell with [Na⁺]_out = 150 mM and [Na⁺]_in = 15 mM at 37°C, which of the following would make the transport of ion into the cell more spontaneous if the potential across the membrane that has an absolute value of 60 mV with the inside of the cell more negative?

Decreasing the ratio of [Na⁺]_in to [Na⁺]_out

Increasing the concentration [Na⁺]_in

Decreasing the temperature of the cell

Increasing the negative charge outside of the cell

Decreasing the ratio of [Na⁺]_in to [Na⁺]_out

What is the most likely fate of pyruvate in mammalian muscle during very vigorous exercise?

Conversion to acetyl-CoA via the pyruvate dehydrogenase complex.

Conversion to oxaloacetate, to replenish citric acid cycle intermediates via anaplerotic reactions.

Conversion to lactate via lactate dehydrogenase.

Transport out of the muscle cell into the bloodstream.

Conversion to lactate via lactate dehydrogenase.

The Saharan Desert was once home to an abundant fish population such as Catfish and Pupfish. To withstand the drastic temperature changes that occur from the extremely hot daytime and extremely cold night time, these fish changed their membrane lipid composition at different times of the day. Which of these would make most sense for these fish?

During day time, desert fish altered their cell membranes to have shorter fatty acid chains.

During day time, desert fish altered their cell membranes to include a cell wall.

During day time, desert fish altered their cell membranes to have more saturated fatty acid chains.

During day time, desert fish altered their cell membranes to have more unsaturated fatty acid chains.

During day time, desert fish altered their cell membranes to have more saturated fatty acid chains.

Given the following reaction:

1,3-BPG + ADP <-> 3-phosphoglycerate + ATP                ΔG°’ = -18.9 kJ/mol

Which one of these compounds will most readily accept a phosphate group?

3-phosphoglycerate

ADP

ATP

1,3-BPG

ADP

Order the following steps from a tyrosine kinase signaling pathway from beginning to end. Credit is only given for exact matches.

Activation of the Ras protein.

Binding of the ligand to the receptor

Dimerization of the receptor

Phosphorylation of a kinase by an identical kinase

Binding of the ligand to the receptor

Dimerization of the receptor

Phosphorylation of a kinase by an identical kinase

Activation of the Ras protein.

A toxin binds to the alpha subunit of the G-protein on the 7TM receptor, preventing it from releasing GDP and hence preventing it from binding GTP. A potential solution to counter this toxin is the introduction of a molecule that mimics the structure of GTP. Will this solution work? Why or why not? 

No - the toxin will degrade the GTP mimic.

Yes - the G-protein will bind the GTP mimic and be activated.

No - if the G-protein cannot bind GTP, it will also be unable to bind a molecule that has a similar structure to it. 

Yes - this will cause the GDP to be released. 

No - if the G-protein cannot bind GTP, it will also be unable to bind a molecule that has a similar structure to it. 

The potassium channel’s selectivity filter is specific to positive ions. Why is this?

Anions do not have the hydration shells necessary to move into the channel.

Anions are larger than cations and hence too large to pass through the opening.

Groups with partial negative charges are present within the filter.

None of these

Groups with partial negative charges are present within the filter.

What properties of ATP make it an especially effective phosphoryl-transfer-potential compound?

I. The increase of charge-charge repulsion upon hydrolysis
II. Resonance stabilization of Pi
III. Increase in entropy upon hydrolysis
IV. Stabilization by increase in free energy of inorganic phosphate

II and III only

II, III, and IV only

I, II, III, and IV

I only

I and III only

II and III only

The sodium potassium pump will open to the inside of the cell when

an active G-protein phosphorylates the receptor

sodium ions flow with their concentration gradient into the cell

a calcium secondary messenger binds to the receptor

an ATP binds to an Asp residue, replacing an inorganic phosphate

an ATP binds to an Asp residue, replacing an inorganic phosphate

In cells, NADPH serves as a carrier of which of the following?

Methyl groups

Phosphate groups

Electrons

Acetyl groups

Hydroxyl groups

Electrons

Activation of a G proteins in response to hormone binding requires the binding of _______ to the _______ subunit.

GTP; α

GDP; α

GDP; γ

GTP;β

GDP; β

GTP; α

In humans, pyruvate can be converted to

acetyl-CoA only.

lactate only.

acetyl-CoA or lactate.

ethanol only.

acetyl-CoA or lactate.

Transport that allows for spontaneous movement but only with assistance of membrane proteins is called

active transport

facilitated diffusion

none of these

simple diffusion

facilitated diffusion

Which of these secondary messengers acts in the insulin signaling pathway?

Calcium

PIP3

 cAMP

None of these

PIP3

A certain transporter has a mechanism in which it has two conformations: one  open to the inside of the cell and the other open to the outside of the cell. This transporter moves two ions, A and B. In one conformation, both ion A and ion B enter the transporter and bind. In the other conformation, both ion A and ion B are released. Which type of transport does this best describe?

Symport

Facilitated diffusion

Antiport

None of these

Symport

Calculate the ΔG of the transport of a chloride ion out of a cell with a membrane potential that has a magnitude of 50mV. The cell membrane is positively charged on the outside and negatively charged on the inside. [Cl-] on the inside of the cell is 50mM while [Cl-] on the outside is 1mM. Temperature is 25℃ and use 96,485 C/mol as Faraday’s constant.

None of these

+4868 J/mol

-14516 J/mol

-4868 J/mol

+14516 J/mol

-14516 J/mol

The transport of an ion across a membrane against its concentration gradient can be accomplished by:

The antiport of another ion, whether with or against its concentration gradient

The opening of a channel specific for the ion

The co-transport of another ion also against its concentration gradient

The hydrolysis of ATP as a part of the transport mechanism

The hydrolysis of ATP as a part of the transport mechanism

Which of the following is true regarding lipid membrane movement?

Lateral diffusion of lipids occurs rapidly without the use of enzymes

Transverse diffusion of lipids occurs rapidly due to favorable interactions

None of the other answer choices

Lateral diffusion of lipids requires the use of flippases to occur rapidly

Lateral diffusion of lipids occurs rapidly without the use of enzymes

G proteins are ________ when bound to ________.

Active; cAMP

Inactive; cAMP

Inactive; GTP

Inactive; ATP

Active; GDP

Active; GTP

In glycolysis, the change in ATP during the energy investment phase is _______, while the change in ATP during the energy payoff phase is _______. (Negative indicates it was consumed. Positive indicates it was produced)

-1; 3

-4;6

-2; 2

-2; 4

0; 2

-2; 4

Which steps of glycolysis involve ATP consumption?

pyruvate kinase reaction only

pyruvate kinase reaction and phosphofructokinase reaction

hexokinase reaction and phosphofructokinase reaction

hexokinase reaction only

phosphofructokinase reaction only

hexokinase reaction and phosphofructokinase reaction

Consider this rxn which has a ΔG° = +0.4 kJ/mol.

A + B ↔ C + D

1 M A, 1 M B, 0.1 M C and 0.1 M D are added to a container at room temperature. Which of the following statements is true?

ΔG < 0 (i.e., it's negative)

Cannot be determined from the information provided.

ΔG > 0 (i.e., it's positive)

ΔG = 0

ΔG < 0 (i.e., it's negative)

Glycoproteins are composed mostly of carbohydrates.

True

False

False

The sodium potassium pump will open to the outside of the cell when

sodium ions flow with their concentration gradient into the cell

an active G-protein phosphorylates the receptor

an ATP is hydrolyzed to leave an inorganic phosphate bound to an Asp residue

a calcium secondary messenger binds to the receptor

an ATP is hydrolyzed to leave an inorganic phosphate bound to an Asp residue

EGF/Ras is a signaling pathway that has been extensively studied due to its involvement in several types of cancer, which is characterized by uncontrolled cell growth. Given your knowledge of the Ras pathway, which mutation is one that could lead to uncontrolled cell growth?

Irreversible binding of GTP to Ras.

Inhibited dimerization of the receptor.

Degradation of the secondary messenger.

Cross-phosphorylation of tyrosine kinases being blocked.

Irreversible binding of GTP to Ras.

Which of these would NOT terminate a signal cascade?

I) Irreversible binding of the primary messenger to the receptor

II) Degradation of the secondary messenger

II only

Neither I or II will terminate a signaling cascade.

I only

Both I and II will terminate a signaling cascade.

I only

Which of the following cannot be freely secreted into the bloodstream after being absorbed by intestinal cells?

Salts

Lipids

Proteins

Lipids

Carbohydrates

Lipids

CO2 is more reduced than CH4

True

False

False

Which of the following is true about sphingolipids? 

Sphingolipids naturally organize into micelles

They are commonly found in neural tissue as sphingomyelin.

Sphingolipids can sometimes be glycerophospholipids, depending on the bonds in their head group.

Sphingolipids have one glycerol, one polar head group, and one fatty acid tail.

They are commonly found in neural tissue as sphingomyelin.

A metabolic process uses NADP+ / NADPH as its electron carrier. This process is best classified as:

Anabolic

Catabolic

Anabolic

Observe the above diagram of the GLUT1 transporter.

If there is a mutation causing a loss of function in this transporter, how will glucose uptake into the cell be affected?

Glucose uptake will decrease.

Glucose uptake will not be affected.

Glucose uptake will increase.

Glucose uptake will require more energy since this is active transport.

Glucose uptake will decrease.

How does fructose-1,6-bisphosphate work as an effector in glycolysis?

None of these are correct.

It is produced in the first step of glycolysis, so until this is produced, the reactions can not move forward.

It is a positive affecter of pyruvate kinase in the last step in the formation of pyruvate.

It increases the energy charge of the cell, positively affecting PFK.

It is a negative affecter of hexokinase.

It is a positive affecter of pyruvate kinase in the last step in the formation of pyruvate.

In the reaction

1,3-BPG + ADP  -> 3-phosphoglycerate + ATP     ΔG° = -18.8 kJ/mol

Calculate ΔG when [1,3-BPG] = 15mM, [3-phosphoglycerate] = 2mM, [ADP] = 12mM, and [ATP] = 13mM at 25°C. R = 8.314 J mol-1K-1

-23.6 kJ/mol

+4.8 kJ/mol

-14.0 kJ/mol

-4.8 kJ/mol

-23.6 kJ/mol

The oxidative phase of the pentose phosphate pathway _______.

is regulated primarily by levels of NADP+

produces intermediates of glycolytic and gluconeogenic pathways

consumes NADPH and utilizes a carboxylation reaction

consists of entirely near-equilibrium reactions

is regulated primarily by levels of NADP+

Which of these statements are true?

1. Some, but not all, of the enzymes used in glycolysis are used in gluconeogenesis, just running in reverse.

2. Fructose-2,6-bisphosphate is an important effector in both glycolysis and gluconeogenesis

3. The gluconeogenesis pathway has one more step than the glycolysis pathway

I, II, and III

I and II only

I only

I and III only

II and III only

III only

II only

I, II, and III

The regulatory enzyme of cholesterol synthesis is most active when

Phosphorylated

Dephosphorylated

Dephosphorylated

Which of these are true for glycogen degradation?

I. Glycogen branch points contain only alpha-1,4 linkages, which cannot be cleaved by glycogen phosphorylase.

II. Before the glucose at a branch point can be removed, three residues must be transferred from the branch to the main chain by a debranching enzyme. 

III. Glycogen phosphorylase can cleave alpha-1,4 bonds and alpha-1,6 bonds, but has a higher affinity for the main chain glucose residues. 

I only

III only

II and III only

I and II only

I, II, and III

II only

II only

In what form are fatty acids transported across the mitochondrial inner membrane?

Acyl-CoA

Acyl Ester

Acyladenylate

Acyl-Carnitine

Acyl-Carnitine

Which of the following is a negative effector of the enzyme phosphoenolpyruvate carboxykinase? 

ADP

ATP

Alanine

NADH

ADP

When phosphorylated, the ____ domain of the bifunctional enzyme is active and ____ is stimulated.

PFK-2, gluconeogenesis

F-2,6-BPase, glycolysis

PFK-2, glycolysis

F-2,6-BPase, gluconeogenesis

F-2,6-BPase, gluconeogenesis

The outputs of the Pentose Phosphate Pathway vary under different cellular conditions.  If your body has a balanced need for both NADPH and ribose-5-phosphate, which of the following is the best choice for how your body would react?

Your body would run the oxidative phase of the PPP and then use the non-oxidative phase to generate the metabolites needed so it can run through glycolysis.

Your body would run just the non-oxidative phase of the PPP.

Your body would run the oxidative phase of the PPP and then use the non-oxidative phase and gluconeogenesis to recycle the ribulose carbons into so it can run the oxidative phase again.

Your body would run just the oxidative phase of the PPP.

Your body would run just the oxidative phase of the PPP.

Which of the following explains why glucose-6-phosphatase is found in the liver, but not in most other cells?

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate in the liver allowing the glucose to enter the pentose phosphate pathway which occurs mostly in the liver.

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate when the glucose concentration in the blood stream decreases which allows glucose to flow from liver cells to blood.

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate in the liver so that the glucose can enter the glycolytic pathway.

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate allowing it to enter the glycogen synthesis pathway for long term storage in the liver.

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate in the liver because the liver is the primary location for gluconeogenesis and this allows glucose to enter that pathway.

Glucose 6-phosphatase removes a phosphate from glucose 6-phosphate when the glucose concentration in the blood stream decreases which allows glucose to flow from liver cells to blood.

Which of these is considered a regulatory enzyme in the citric acid cycle?

isocitrate dehydrogenase

succinate dehydrogenase

malate dehydrogenase

succinyl-CoA synthetase

succinyl-CoA synthetase

Pyruvate Dehydrogenase can be regulated by

Covalent modification only

Allosteric effectors only

Both covalent modification and allosteric effectors.

Both covalent modification and allosteric effectors.

Given the following reduction data and concentrations, calculate the redox reaction potential for the reduction of pyruvate by NADH.  Assume the following concentrations:  NADH = 11 μM, NAD⁺ = 13 μM, pyruvate = 7 μM, lactate = 9 μM. 

Pyruvate + 2H+ + 2e- → Lactate	ε°'  = -0.190
NAD+ + H+ + 2e- → NADH	ε°'  = -0.320

• Temperature = 37°C

• R = 8.314 J/mol⋅K

• F = 96,485 C/mol

• pH = 7

0.045

-0.124

-0.226

-0.045

0.226

0.124

In ATP Synthase, protons move across the mitochondrial membrane in which direction?

From the cytosol to the outer membrane

From the outer membrane to the intermembrane space

From the intermembrane space to the matrix

From the matrix to the intermembrane space

From the intermembrane space to the matrix

An inactivating mutation in the translocase enzyme associated with the carnitine-acyl transferase enzymes would result in ________.

a breakdown in reciprocal regulation, with both fatty acid degradation and fatty acid synthesis proceeding at high rates.

acyl-CoA being unable to be exported to the cytoplasm for beta-oxidation

acyl-CoA building up in the cytoplasm where it is unable to be broken down

acyl-CoA building up in the cytoplasm where it is unable to be broken down