Deck 26: The Pentose Phosphate Pathway

Question 1

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
Two molecules of ____________ are formed in phase II of the pentose phosphate pathway.

Answer 1

k

Question 2

_________________ is converted to xylulose 5-phosphate by the enzyme phosphopentose epimerase.

Answer 2

Ribulose-5-phosphate

Question 3

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
A deficiency of glucose 6-phosphate can cause hemolytic anemia. This is due to a loss in activity in which enzyme in red blood cells?

Answer 3

h

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) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
____________ results in a C3 and a C7 carbohydrate from two C5 carbohydrate precursors.

Question 5

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
____________ is the key source of biosynthetic reducing equivalents.

Question 6

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
The prosthetic group ____________ is tightly bound to the enzyme transketolase.

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) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
____________ and transketolase are the enzymes that link glycolysis and the pentose phosphate pathway.

Question 8

The enzyme transketolase transfers a _________________-carbon fragment from a ketose to an aldose.

Question 9

NADPH is required by the liver and adipose for synthesis of _________________.

Question 10

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
Excess carbons of the pentose phosphate pathway are shunted to what other metabolic pathway?

Question 11

Isomers with multiple asymmetric centers differing in only one asymmetric center is/are a(n) _________________.

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) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
_________________ is the committed step of the pentose phosphate pathway.

Question 13

_________________ is the enzynme that catalyzes the hydrolysis of the ester linkage of the lactone, resulting in the ring opening.

Question 14

Hemolytic anemia is a result of increase in reactive oxygen species. The manifestation of the disease is actually caused by a defect in _________________.

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) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
The second phase of the pentose phosphate pathway is the ____________ phase.

Question 16

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
____________ is a substrate for the pentose phosphate pathway.

Question 17

The oxidative phase of the pentose phosphate pathway produces _________________, which is required for lipid biosynthesis.

Question 18

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
The two key components required for growth are _________________ and biochemical reducing power.

Question 19

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) nonoxidative
b) oxidative
c) transketolase
d) glucose 6-phosphate
e) reducing equivalents
f) thiamine pyrophosphate
g) transaldolase
h) glutathione reductase
i) glycolysis
j) NADH
k) fructose 6-phosphate
l) NADPH/pentose phosphate pathway
m) glucose
Ribulose 5-phosphate is the result of the ____________ phase.

Question 20

Hemolytic anemia is caused by a deficiency of the enzyme _________________.

Question 21

Which sugar(s) is/are converted into ribulose 5-phosphate by a single enzymatic step?

A) ribose 5-phosphate
B) xyulose 5-phosphate
C) erythrose 4-phosphate
D) A and B
E) C and C

Question 22

What is the net reaction of the transketolase and transaldolase steps?

A) 3C52C6 + C3
B) 2C5C6 + C4
C) 3C5C6 + 3C3
D) 2C52C4 + C2
E) None of the above.

Question 23

The pentose phosphate pathway:

A) is stimulated by NADH.
B) is stimulated by NADPH.
C) operates primarily in nondividing cells.
D) is contained within the mitochondria of adipose cells.
E) None of the above.

Question 24

Which enzyme controls the pentose phosphate pathway?

Question 25

Glucose 6-phosphate dehydrogenase is inhibited by low levels of:

A) NADPH.
B) NADP+.
C) ribose 5-phosphate.
D) A and C.
E) B and C.

Question 26

How is the pentose phosphate pathway regulated?

Question 27

Several physiological modes are possible for the metabolic need for NADPH, ribose 5-phosphate, and ATP. In one scenario, such as found in adipose tissue, much more NADPH is required than ribose 5-phosphate. How is this maintained?

Question 28

Reduced glutathione maintains red blood cell structure by:

A) protecting against falciparum malaria.
B) maintaining hemoglobin structure.
C) preventing Heinz body formation.
D) A and C.
E) B and C.

Question 29

In mode two:

A) the needs for NADPH and ribose 5-phosphate are balanced,
B) much more NADPH than ribose 5-phosphate is required.
C) more ribose 5-phosphate than NADPH is required.
D) NADPH and CO2 are required.
E) excess NAD+is required. .

Question 30

In the nonoxidative phase of the pentose phosphate pathway, two reactions are catalyzed by transketolase. What are the substrates and products of these reactions?

Question 31

Which of the following reactions is not part of the pentose phosphate pathway?

A)
B)
C)
D)
E) All of the above.

Question 32

How can a deficiency of glucose 6-phosphate confer a physiological advantage?

Question 33

ATP is called the energy currency. The currency of reducing power is:

A) NADPH.
B) NADH.
C) AMP.
D) ADP.
E) None of the above.

Question 34

NADPH is required for which of the following detoxification reactions or enzymes?

A) cytochrome P450 monooxygenase
B) reduction of glutathione(ox)
C) deamination of serine
D) A and B
E) All of the above.

Question 35

Which biosynthetic pathway requires NADH?

A) cholesterol
B) fatty acid
C) nucleotide
D) All of the above.
E) None of the above.

Question 36

In the nonoxidative stage of the pentose phosphate pathway, intermediates of _____________ are produced.

A) the citric acid cycle
B) glycolysis
C) glycogen degradation
D) A and C
E) B and C

Question 37

Under what conditions might the pentose phosphate pathway produce large amounts of NADPH without significant net production of ribose 5-phosphate?

A) synthesis of fatty acids in the liver
B) when pyruvate is synthesized to generate ATP
C) when cells are rapidly dividing
D) A and C
E) B and C

Question 38

______________ oxidizes the C3 hydroxyl to a ketone.

A) Lactonase
B) Glucose 6-phosphate dehydrogenase
C) Transaldolase
D) Transketolase
E) 6-phosphogluconate dehydrogenase

Question 39

What is the common feature of the mechanism of the metabolic oxidations of 6-phosphogluconate and isocitrate?

Question 40

The purpose of the pentose phosphate pathway is to:

A) generate ATP.
B) generate NADPH.
C) synthesize five-carbon sugars.
D) A and B.
E) B and C.

Question 41

What are the reactions in the oxidative phase of the pentose phosphate pathway?

Question 42

How does NADPH protect red blood cells from hemolysis?

Question 43

What is a primary difference between the oxidation of glucose to CO2 by glycolysis and the citric acid cycle versus the oxidation via the pentose phosphate pathway?