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Biochemistry > Glycolysis > Flashcards

Glycolysis Flashcards

1
Q

Glycolysis
a. does not require O2 to generate energy.
b. requires O2 to generate energy.
c. is inhibited by O2.
d. rate is increased in the presence of O2.

A

a

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2
Q

The fate of pyruvate produced during glycolysis depends primarily on the availability of
a. NAD+
to keep the pathway going.
b. molecular oxygen.
c. ADP for conversion to ATP.
d. coenzyme A for further metabolism of pyruvate.
e. phosphoric acid for the synthesis of ATP.

A

b

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3
Q

In aerobic metabolism, what is the fate of pyruvate produced by glycolysis?
a. Pyruvate loses carbon dioxide, and the remaining two carbon atoms become linked to coenzyme A.
b. Pyruvate loses carbon dioxide, producing acetaldehyde, which, in turn, is reduced to ethanol.
c. Pyruvate is reduced to lactate.
d. None of these

A

a

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4
Q

In humans, pyruvate can be converted to
a. acetyl-CoA only.
b. lactate only.
c. ethanol only.
d. acetyl-CoA and lactate.

A

d

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5
Q

Which of the following is not an end product of glucose metabolism via either aerobic or anaerobic means?
a. ethanol
b. carbon dioxide
c. lactate
d. fructose
e. all of these are end products of glucose metabolism

A

d

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6
Q

What is the net ATP yield per glucose during glycolysis?
a. 1
b. 2
c. 3
d. 4
e. 6

A

b

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7
Q

In the conversion of glucose to pyruvate, how many of the actual steps involve electron transfer?
a. none
b. 1
c. 2
d. 3
e. 4

A

b

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8
Q

The order of compounds in the conversion of glucose to pyruvic acid is as follows: (PEP = phosphoenolpyruvate)

a. Fructose-bisphosphate, fructose-6-phosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid, PEP.

b. Fructose-6-phosphate, fructose-bisphosphate, PEP, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid.

c. Fructose-6-phosphate, fructose-bisphosphate, 1,3-phosphoglyceric acid, 3-phosphoglyceric acid, PEP.

d. Fructose-6-phosphate, fructose-bisphosphate, 3-phosphoglyceric acid, 1,3-phosphoglyceric acid, PEP.

e. Fructose-bisphosphate, fructose-6-phosphate, 3-phosphoglyceric acid, 1,3-phosphoglyceric acid, PEP.

A

c

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9
Q

Which of the following is not true?
a. Corn is the only source of biofuels
b. Biofuels are related to glycolysis because fermentation is an end process of anaerobic glycolysis
c. Corn, wood, animal dung, and many other products can produce biofuels
d. Many carbohydrate sources can produce ethanol

A

a

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10
Q

How many steps in glycolysis have ATP as a substrate or product?
a. zero
b. 1
c. 2
d. 4
e. 6
f. none of these

A

d

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11
Q

Which of the following terms describes an enzyme that transfers a phosphate group from ATP to a substrate?
a. kinase
b. isomerase
c. mutase
d. dehydrogenase

A

a

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12
Q

The ΔG values for glycolytic reactions at physiological conditions may be exergonic, even though the ΔG°’ at
“standard” conditions, may be endergonic.
a. True
b. False

A

a

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13
Q

The reactions where glucose is converted to glucose 6-phosphate and fructose 6-phosphate is converted to fructose
1,5-bisphosphate are examples of:
a. exergonic reactions
b. priming reactions
c. phosphorylation reactions
d. kinase reactions
e. all of these

A

e

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14
Q

The phosphorylation of glucose to glucose 6-phosphate
a. is so strongly exergonic that it does not require a catalyst.
b. is an exergonic reaction not coupled to any other reaction.
c. is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP.
d. is an exergonic reaction that is coupled to the endergonic hydrolysis of ATP.

A

c

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15
Q

The enzyme glucokinase
a. phosphorylates a number of different sugars, including glucose, fructose, and mannose.
b. specifically phosphorylates glucose rather than other sugars.
c. is the only kinase involved in glycolysis.
d. none of the above.

A

b

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16
Q

Which enzyme catalyzes the reaction shown?

“alpha g6p to beta g6p”

a. an epimerase
b. an isomerase
c. a mutase
d. a dehydrogenase

A

b

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17
Q

The binding of glucose to hexokinase
a. is an example of lock-and-key binding of a substrate to the active site of an enzyme.
b. is an example of induced-fit binding of a substrate to the active site of an enzyme.
c. differs from the binding of substrates to other kinases.
d. is not well characterized.

A

b

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18
Q

The phosphorylation of fructose 6-phosphate to fructose-1,6-bisphosphate is the committed step in glycolysis because
a. it is the rate-limiting step.
b. it is the most strongly exergonic step in the pathway.
c. fructose 1,6-bisphosphate can undergo no other reactions than those of glycolysis.
d. two phosphate groups are involved.

A

c

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19
Q

Which of the following sugars can be a substrate for hexokinase?
a. glucose
b. fructose
c. mannose
d. all of these
e. none of these

A

d

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20
Q

Which of the following enzymes interconverts an aldose and a ketose?
a. kinase
b. isomerase
c. mutase
d. dehydrogenase
e. phosphorylase

A

b

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21
Q

Which enzyme is the key regulatory enzyme in glycolysis?
a. Glyceraldehyde-3-phosphate dehydrogenase
b. Enolase
c. Phosphofructokinase
d. Aldolase

A

c

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22
Q

Which of the following exercise(s) allosteric control in the reaction of phosphofructokinase?
a. ATP
b. fructose 2,6-bisphosphate
c. both of these
d. neither of these

A

c

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23
Q

The reaction of fructose 1,6-bisphosphate to give glyceraldehyde-3-phosphate and dihydroxyacetone phosphate is an
example of
a. a reverse aldol condensation.
b. hydrolysis.
c. oxidation.
d. dehydration.

A

a

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24
Q

The equilibrium for isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate is favored because
a. the standard free energy is negative
b. glyceraldehyde-3-phosphate is being continuously drained off for the subsequent reaction in the glycolytic
pathway
c. the value of the equilibrium constant favors the reaction
d. it is driven by the hydrolysis of ATP

A

b

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25
Q

The isomerization of dihydroxyacetone phosphate to give glyceraldehyde 3-phosphate
a. is catalyzed by the enzyme triose phosphate isomerase.
b. requires several enzymes.
c. requires coenzyme A.
d. requires thiamine pyrophosphate

A

a

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26
Q

The step that commits the cell to metabolize glucose is catalyzed by
a. hexokinase.
b. phosphoglucomutase.
c. aldolase.
d. phosphofructokinase.

A

d

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27
Q

The equilibrium for the formation of glyceraldehyde-3-phosphate from dihydroxyacetone phosphate is driven by
a. the negative free energy change for the reaction.
b. having the product of the reaction continuously consumed.
c. coupling to ATP hydrolysis.
d. none of these

A

b

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28
Q

Which of the following enzymes catalyzes the cleavage of fructose bisphosphate into two 3-carbon units?
a. Aldolase
b. Enolase
c. An isomerase
d. A mutase
e. None of these enzymes carries out that reaction.

A

a

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29
Q

Which of the following is not true?
a. Every reaction in a metabolic pathway must have a negative ΔG, or the pathway cannot run.
b. the reaction with the largest negative ÄG is the hexokinase reaction
c. the overall pathway of glycolysis has a negative ÄG
d. all of these are true

A

a

30
Q

Which of the following is true about phosphofructokinase?
a. It is made of a single polypeptide chain
b. It is found in the muscle only
c. It is made up of four subunits, potentially of two different types
d. A person who lacks the M subunit does not have the glycolytic pathway

A

c

31
Q

Which of the following is true about phosphofructokinase?
a. It is a tetramer composed of different combinations of the M and L subunits
b. there are two isozymes, M4 and L4
c. there are a total of 6 isozyme types in the body
d. It is a dimer composed of M and L subunits
e. none of these

A

a

32
Q

Which of the following terms describes an enzyme that catalyzes electron transfer reactions?
a. dehydrogenase
b. isomerase
c. kinase
d. phosphatase

A

a

33
Q

Which of the following enzymes forms a thioester using a cysteine residue as a key intermediate?
a. hexokinase
b. triose phosphate isomerase
c. glyceraldehyde-3-phosphate dehydrogenase
d. enolase

A

c

34
Q

In glycolysis, ATP is synthesized by
a. substrate-level phosphorylation.
b. oxidative phosphorylation.
c. photophosphorylation.
d. both substrate-level and oxidative phosphorylation.
e. all three of the above methods.

A

a

35
Q
  1. Which group of small molecules best fit the boxes associated with the reaction shown?

(picture)

    a                 b               c I. ATP              ADP           H2O II. NADH        NAD+           Pi III. NAD+        NADH         H2O IV. NAD+         NADH         Pi
A

d

36
Q
  1. What kind of enzyme catalyzes the reaction shown?

(picture)

a. an epimerase
b. an isomerase
c. a mutase
d. a dehydrogenase

A

d

37
Q

Enolase catalyzes
a. the cleavage of fructose bisphosphate into two 3-carbon units.
b. the dehydration of 2-phosphoglycerate.
c. the conversion of phosphoenolpyruvate to pyruvate.
d. the conversion of glucose-6-phosphate to fructose-6-phosphate.

A

b

38
Q

The nicotinamide-binding region in glyceraldehyde-3-phosphate dehydrogenase is similar to all other NAD binding
domains.
a. True
b. False

A

a

39
Q

During glycolysis, ATP is synthesized from ADP and a phosphate group transferred from an acid anhydride.
a. True
b. False

A

a

40
Q
  1. What is the name of the pictured glycolytic intermediate?

(picture)

a. 1-phosphoglycerate
b. glyceraldehyde-3-phosphate
c. dihydroxyacetone phosphate
d. 3-phosphoglycerate

A

d

41
Q

Which of the following is required for substrate-level phosphorylation?
a. The substrate must contain multiple phosphate groups.
b. Molecular oxygen must present.
c. The standard free energy of the hydrolysis reaction is more negative than that for hydrolysis of the new
phosphate compound being formed.
d. All of the above are necessary for substrate-level phosphorylation.

A

c

42
Q
  1. Which enzyme catalyzes reaction the reaction shown?

(Picture)

a. enolase
b. pyruvate dehydrogenase
c. pyruvate kinase
d. phosphoglycerate mutase

A

c

43
Q

The amino acid cysteine is important in adding a second phosphate to glyceraldehyde phosphate in the
glyceraldehyde-3-phosphate dehydrogenase reaction.
a. True
b. False

A

a

44
Q

Which of the following glycolytic enzymes forms a mixed anhydride from phosphoric acid?
a. hexokinase.
b. phosphofructokinase.
c. glyceraldehyde-3-phosphate dehydrogenase.
d. phosphoglycerate kinase.
e. pyruvate kinase.

A

c

45
Q

Which of the following enzymes catalyzes a dehydration reaction?
a. Glyceraldehyde-3-phosphate dehydrogenase
b. Enolase
c. Phosphofructokinase
d. Aldolase

A

b

46
Q

In the conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate
a. an alcohol group is phosphorylated.
b. an alcohol is oxidized to an aldehyde.
c. an alcohol is oxidized to a carboxylic acid.
d. an aldehyde is oxidized to a carboxylic acid.

A

d

47
Q

How many different reactions involve substrate-level phosphorylation during glycolysis?
a. 1
b. 2
c. 3
d. 4
e. 6

A

b

48
Q

The reduction of pyruvate to lactate
a. allows for recycling of NAD+
b. is the process that aids in the recovery of sore muscles after exercise.
c. is accompanied by phosphorylation of ADP.
d. does not occur in aerobic organisms.

A

a

49
Q

Anaerobic metabolism can occur in all these organisms or cells, except:
a. Yeast
b. Red blood cells
c. Muscle tissue that is working very fast
d. Lactobacillus in milk
e. Anaerobic metabolism can occur in all of these.

A

e

50
Q

Which of the following enzymes of anaerobic metabolism is not tetrameric?
a. Hexokinase
b. Phosphofructokinase
c. Pyruvate kinase
d. Lactate Dehydrogenase

A

a

51
Q

Which of the following is not true?
a. Multiple isozymes of lactate dehydrogenase are used as clinical means for diagnosing heart attacks.
b. Two enzymes involved in anaerobic glycolysis are found as isozymes with 5 different forms
c. The M4 version of lactate dehydrogenase predominates in heart tissue
d. After a myocardial infarction, the blood serum levels of MH3 and H4 isozymes increase

A

c

52
Q

During anaerobic metabolism in yeast, the carbons of glucose end up in
a. CO2
b. ethanol.
c. lactic acid.
d. both CO2 and ethanol.
e. all of these

A

d

53
Q

Which of the following enzymes relies on thiamine pyrophosphate as a cofactor?
a. pyruvate decarboxylase
b. pyruvate kinase
c. lactate dehydrogenase
d. enolase

A

a

54
Q

Fetal alcohol syndrome
a. can be prevented by administering large doses of vitamin B1 to pregnant women
b. can be prevented by administering large doses of the vitamin niacin (nicotinic acid) to pregnant women
c. can be reversed by administering acetaldehyde
d. can be detected by measuring the level of acetaldehyde in the bloodstream of a pregnant woman

A

d

55
Q

During anaerobic metabolism in red blood cells, the carbons of glucose end up in
a. CO2.
b. ethanol.
c. lactic acid.
d. both CO2 and ethanol.
e. all of the above.

A

c

56
Q

Alcohol dehydrogenase resembles lactate dehydrogenase in that it
a. is nonallosteric.
b. is a dimer.
c. uses NAD+
as a coenzyme.
d. is not found in aerobic organisms.

A

c

57
Q

Thiamine pyrophosphate is a coenzyme
a. frequently encountered in oxidation-reduction reactions.
b. required for the phosphorylation of ADP.
c. involved in transfers of two-carbon groups.
d. involved in transfers of one-carbon groups.

A

c

58
Q

The fate of NADH from glycolysis depends on whether conditions are anaerobic or aerobic.
a. True
b. False

A

a

59
Q

Methanol is extremely toxic, but not directly. In the body, it is converted into formaldehyde; that’s what’s actually the
poison. What kind of enzyme catalyses this conversion?
a. a kinase
b. an isomerase
c. a mutase
d. a dehydrogenase

A

d

60
Q

What is the relationship between glycolysis and cancer?
a. cancer cells lack a glycolytic pathway
b. cancer cells use a modified version of glycolysis
c. cancer cells exhibit a much higher level of anaerobic glycolysis than normal cells
d. none of these

A

c

61
Q

The percentage of energy captured as ATP during the conversion of glucose to lactate is closest to
a. 10%.
b. 30%.
c. 50%.
d. 75%.
e. 90%

A

b

62
Q

Consider the following information:

phosphoenolpyruvate → pyruvate ΔG°’ = −61.9 kJ/mol

ADP + Pi → ATP
ΔG°’ = +30.5 kJ/mol

How many molecules of ATP might theoretically have been produced when coupled to the conversion of one molecule phosphoenolpyruvate to pyruvate?

a. 1
b. 2
c. 3
d. 4

A

b

63
Q

If glycolysis did not lead to the production of ATP, the overall process would
a. release less energy
b. release more energy
c. absorb energy
d. not take place in aerobic organisms

A

b

64
Q

When humans consume ethanol, the first step in its metabolism is:
a. conversion to lactate
b. conversion to acetaldehyde
c. conversion to acetone
d. production of fat

A

b

65
Q

Which of the following enzymes of glycolysis is not involved in regulation of the pathway?
a. Hexokinase
b. Phosphofructokinase
c. Aldolase
d. Pyruvate kinase
e. All of these proteins regulate glycolysis.

A

c

66
Q

How many enzymes of glycolysis are control points for the pathway?
a. 1
b. 2
c. 3
d. 4
e. All the enzymes serve as control points.

A

c

67
Q

An enzyme not involved in the control of glycolysis is
a. hexokinase.
b. triose phosphate isomerase.
c. pyruvate kinase.
d. phosphofructokinase

A

b

68
Q

Which of the following statements is true of the glycolytic pathway?

a. Each reaction in the glycolytic pathway is catalyzed by a single enzyme, acetyl CoA dehydrogenase.

b. In each reaction in the pathway, one molecule of ATP is hydrolyzed for each molecule of glucose that is metabolized.

c. In each reaction in the glycolytic pathway, two NADP molecules are released that make coupled exergonic reactions possible.

d. Each reaction has a net gain of three ATP molecules for each glucose molecule processed in glycolysis.

A

b

69
Q

Ethanol is mixed with _____ when it is used as fuel in an internal combustion engine.
a. biodiesel
b. gasoline
c. methanol
d. butanol

A

b

70
Q

Phosphorylation of fructose 6-phosphate to produce fructose-1,6-bisphosphate happens in the _____ step of
glycolysis.
a. first
b. second
c. third
d. fourth

A

c

71
Q

The enzyme _____ helps in the conversion of 3-phosphoglycerate to 2-phosphoglycerate during glycolysis.

a. indoleglycerol phosphate synthase
b. phosphoglyceromutase
c. phosphoglycerate kinase
d. glycerol diphosphatase

A

b

72
Q

During glycolysis, enolase, the enzyme that catalyzes the conversion of 2-phophoglycerate to phosphoenolpyruvate
requires _____ as a cofactor.
a. Fe2+
b. Cu2+
c. Mg2+
d. Zn2+

A

c

Biochemistry (21 decks)

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