Deck 16: Glycolysis

Question 1

In alcoholic fermentation, the decarboxylation of pyruvate requires a coenzyme that contains the vitamin ______________.

Answer 1

thiamine, or B1

Question 2

The regeneration of ______________ in the reduction of pyruvate to lactate sustains glycolysis under anaerobic conditions.

Answer 2

NAD+

Question 3

Glucose is the most stable hexose because the hydroxyl groups are all in the ______________position.

Answer 3

axial

Question 4

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
____________: This molecule is an allosteric inhibitor of phosphofructokinase.

Question 5

Glycolysis produces a net of ______________ moles of ATP per 1 mole of glucose.

Question 6

The key regulatory enzyme for glycolysis is ______________.

Question 7

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
____________: These organisms cannot survive in the presence of oxygen.

Question 8

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
____________ is the enzyme responsible for converting galactose to be used in the glycolytic pathway.

Question 9

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
____________ is the principle carbohydrate in living systems.

Question 10

A potent allosteric activator of liver phosphofructokinase is ______________, which is produced from fructose-6-phosphate by PFK2.

Question 11

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
The intermediate that is necessary for the conversion of galactose to glucose is ____________.

Question 12

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
The transporter that is responsible for fructose uptake in the intestine is ____________.

Question 13

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
____________ is the transporter found in the pancreas and liver.

Question 14

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
The product of aerobic glycolysis is ____________.

Question 15

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
An allosteric activator of glycolysis is ____________.

Question 16

The first irreversible enzymatic reaction unique to a metabolic pathway is called the ______________ step

Question 17

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) obligate anaerobes
b) AMP
c) pyruvate
d) NAD+
e) glucose
f) UDP-glucose
g) GLUT5
h) facultative anaerobes
i) ATP
j) magnesium
k) galactokinase
l) GLUT2
m) galactose isomerase
The substance ____________ must be regenerated for glycolysis to proceed.

Question 18

______________ mediate the thermodynamically downhill movement of glucose across plasma membranes.

Question 19

In the absence of oxygen, ______________ increases the expression of most glycolytic enzymes and the glucose transporters GLUT1 and GLUT3.

Question 20

______________ are enzymes that catalyze the transfer of a phosphoryl group from ATP to an acceptor.

Question 21

Which two isomerization reactions occur in glycolysis? Why are these steps necessary?

Question 22

At equilibrium, there is far more DHAP than GAP. Yet the conversion of DHAP by triose phosphate isomerase proceeds readily. Why?

Question 23

What is the function of a thioester intermediate such as the one formed from GAP?

A) It speeds up the actual reaction so that more product can be made.
B) The thioester shifts the equilibrium of the first stage of the reaction.
C) The thioester allows the two-step reaction to be coupled so the second reaction, the energetically unfavorable phosphorylation, can proceed.
D) The thioester intermediate induces a conformational change that alters the enzyme specificity.
E) The thioester prevents the formation of metabolically unfavorable side products.

Question 24

Lactose intolerance is caused by a deficiency of:

A) lactase.
B) elastase
C) lactose.
D) sucrase.
E) None of the above.

Question 25

What reaction is catalyzed by aldolase?

A) isomerization of DHAP to GAP
B) ligation of GAP and DHAP
C) reversible cleavage of F-1,6-BP to DHAP and GAP
D) cleavage of DHAP to GAP
E) irreversible aldol condensation of DHAP and GAP

Question 26

During exercise, glycolysis is stimulated by a:

A) high-energy charge of the cell.
B) feed-forward stimulation of pyruvate kinase.
C) negative feedback inhibition on hexokinase.
D) A and C.
E) All of the above.

Question 27

Why is it important that the glycolytic and gluconeogenic pathways are reciprocally regulated?

Question 28

Which two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate?

A) glyceraldehyde-3-phosphate and 3-phosphoglycerate
B) glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
C) pyruvate and phosphoenolpyruvate
D) enolase and 2-phosphoglycerate
E) glyceraldehyde-3-phosphate and pyruvate

Question 29

How are the glycolytic enzymes regulated?

A) through transcriptional control
B) through reversible phosphorylation
C) through allosteric control
D) All of the above.
E) None of the above.

Question 30

What is the function of glyceraldehyde 3-phosphate dehydrogenase?

A) oxidation by NAD+ and the formation of acyl phosphate
B) oxidation of the alcohol to an aldehyde
C) dehydration and dephosphorylation of GAP
D) hydrolysis of GAP
E) None of the above.

Question 31

What is the purpose of phosphorylating glucose in cytosol?

A) to trap glucose in the cell
B) to destabilize glucose and facilitate the next series of metabolic steps
C) to convert it to a more soluble form
D) All of the above.
E) A and B

Question 32

What is substrate-level phosphorylation?

A) phosphorylation of AMP by ATP
B) ATP synthesis when the phosphate donor is a substrate with high-phosphoryl-transfer potential
C) phosphorylation of glycolytic intermediates
D) phosphorylation of ATP coupled to an ion gradient
E) ATP and AMP synthesis from two molecules of ADP

Question 33

Why is glucose the most stable hexose?

Question 34

What is a common mechanistic feature of kinases?

A) Phosphoryl groups are transferred from AMP to an acceptor.
B) The binding of substrate induces cleft closing.
C) Kinases convert aldoses to ketoses.
D) All of the above.
E) None of the above.

Question 35

Both hexokinase and glucokinase phosphorylate glucose. The function of glucokinase is to phosphorylate glucose in liver cells as a means to regulate blood-sugar levels. Would you expect its KM to be higher or lower than that of hexokinase?

Question 36

Cancer-driven hypoxia brings about the induction of which genes involved in glycolysis?

A) GLUT3
B) hexokinase
C) aldolase
D) All of the above.
E) None of the above.

Question 37

What are the primary metabolic fates of pyruvate?

A) ethanol
B) lactate
C) acetyl CoA
D) All of the above.
E) None of the above.

Question 38

Which of the following is a reason that glucose is a common metabolic fuel used by living organisms?

A) It has a stable ring structure and is unlikely to glycosylate proteins.
B) It has been found as one of the monosaccharides formed under prebiotic conditions.
C) It is the only sugar used by the brain.
D) A and B.
E) A, B, and C.

Question 39

Fructose can enter glycolysis at two distinct points, depending on the tissue. How is fructose metabolized in adipose tissue?

A) Fructose is cleaved to two molecules of GAP.
B) Fructose is converted to fructose 1-phosphate.
C) Fructose is converted to fructose 6-phosphate.
D) Fructose is cleaved to GAP and DHAP.
E) Fructose is converted to glucose, which enters the pathway.

Question 40

What type of enzyme catalyzes the intramolecular shift of a chemical group?

A) hydrolase
B) kinase
C) dehydrogenase
D) mutase
E) None of the above.

Question 41

Why is it more sensible for phosphofructokinase, rather than hexokinase, to be an important control step?

Question 42

What are fermentations?

Question 43

What are glucose transporters and how do the different types of transporters differ?

Question 44

How is the conversion of phosphoenolpyruvate to pyruvate accompanied by ATP formation?

Question 45

How is glycolysis maintained under anaerobic conditions?

Question 46

Describe the two isoforms of pyruvate kinase.

Question 47

Describe the biochemical explanation for galactosemia.

Question 48

How does citrate influence glycolysis?

Question 49

There are several key regulatory steps in which glycolysis in muscle is left "on" and in liver the same pathway is "off" or inhibited. What are these steps and why are they important?

Question 50

Describe how pyruvate kinase regulation occurs and how this is important in the regulation of glycolysis.