Deck 18: Preparation for the Cycle

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________: Pyruvate is decarboxylated at this active site in PDH.

Answer 1

k

Question 2

A deficiency in the vitamin thiamine causes the disease ____________.

Answer 2

Beriberi

Question 3

PDH is inactivated when it the enzyme is __________________.

Answer 3

phosphorylated

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
In the presence of oxygen, pyruvate is converted to ________________.

Question 5

E1 of the PDH complex requires the coenzyme __________________ for proper activity.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________ is caused by a deficiency in vitamin B1.

Question 7

E2 of the PDH complex contains a lipoyl group that is covalently attached to a __________________ residue of the enzyme.

Question 8

__________________ is the PDH subunit responsible for the regeneration of the oxidized form of lipoamide.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________: The type of enzyme regulation process that inhibits the PDH complex.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
Where does the citric acid cycle take place in the cell?

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
The coenzyme ________________ is the prosthetic group in the decarboxylation of pyruvate.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
The activated carrier of acyl groups is ________________.

Question 13

__________________ inserts the lipoamide arm of the Sulfhydryl (− SH) domain deep into the channel in E1.

Question 14

A __________________ is the critical functional group of lipoamide responsible for carrying acetyl groups and maintaining the free energy of CoA.

Question 15

__________________ provides a flexible linkage for substrate to move between active sites on the PDH.

Question 16

The high-energy charge which results in increasing concentration of NADH __________________ the activity of PDH.

Question 17

Decarboxylation, oxidation, and __________________ are the three steps critical to preserve the free energy derived from decarboxylation of the PDH complex.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________: Arsenite inhibits the function of this component of the PDH.

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) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________ is a large, multi-subunit enzyme complex that links glycolysis and the citric acid cycle under aerobic conditions.

Question 20

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
a) scurvy
b) phosphorylation
c) beriberi
d) mitochondria
e) acetyl CoA
f) E3
g) thiamine pyrophosphate
h) lipoamide
i) pyruvate dehydrogenase
j) coenzyme A
k) E1
l) glyoxylate cycle
________________ provides a flexible linker between active siteswithin the pyruvate dehydrogenase (PDH) complex.

Question 21

Which of the following conditions will activate PDH kinase, which catalyzes the phorphorylation and inactivation of E1 in the PDH complex?

A) elevated concentrations of NADH and ATP
B) elevated concentrations of NAD+ and ADP
C) Ca2+
D) insulin
E) elevated concentrations of acetyl CoA

Question 22

The citric acid cycle is also known as the:

A) Krebs cycle.
B) Cori cycle.
C) tricarboxylic acid cycle.
D) A and B.
E) A, B, and C.

Question 23

Pyruvate dehydrogenase is _______________ when ATP-ADP ratios are high.

A) activated
B) inhibited
C) phosphorylated
D) B and C
E) A and C

Question 24

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of acetyl CoA from pyruvate?

A) thiamine, riboflavin, niacin, lipoic acid, and pantothenic acid
B) thiamine, riboflavin, niacin, lipoic acid, pantothenic acid, and biotin
C) thiamine, riboflavin, niacin, and biotin
D) thiamine, riboflavin, and lipoic acid
E) None of the above.

Question 25

Beriberi symptoms are similar to those of which disease?

A) arsenite poisoning
B) lactic acidosis
C) Type II diabetes
D) scurvy
E) cancer

Question 26

PDH phosphatase deficiency results in which condition?

A) overstimulated PDH
B) low blood glucose
C) chronic elevated plasma lactate
D) high levels of acetyl CoA
E) None of the above.

Question 27

What reaction serves to link glycolysis and the citric acid cycle?

Question 28

Review the fates of pyruvate and the cellular conditions that dictate these fates.

Question 29

What are the three enzyme subunits in the PDH complex and the reactions they catalyze?

Question 30

Acetyl CoA is:

A) the activated form of acyl groups.
B) formed by citrate synthase.
C) the fuel for the citric acid cycle.
D) A and C.
E) A, B, and C.

Question 31

Which enzyme(s) is/are responsible for the following reaction? Pyruvate + CoA + NAD+ → Acetyl CoA + NADH + H+ + CO2

A) acetyl CoA synthetase
B) pyruvate decarboxylase
C) pyruvate dehydrogenase complex
D) A and B
E) A, B, and C

Question 32

What are the steps involved (in order) in the conversion of pyruvate to acetyl CoA?

A) decarboxylation, oxidation, transfer to CoA
B) decarboxylation, transfer to CoA, oxidation
C) oxidation, decarboxylation, transfer to CoA
D) oxidation, transfer to CoA, decarboxylation
E) None of the above.

Question 33

What coenzyme is required for the decarboxylation reaction in PDH and what is the vitamin precursor?

Question 34

How does the term "mad as a hatter" realistically reflect the condition?

Question 35

Milling and polishing rice results in:

A) the loss of the husk of rice.
B) white rice.
C) the potential for Beriberi.
D) the loss of thiamine pyrophosphase.
E) All of the above.

Question 36

Identify the coenzyme, and its vitamin precursor, that is responsible for the transfer of a two-carbon group to coenzyme A, where it forms ahigh-energy thioester bond.

Question 37

Pyruvate is decarboxylated by which subunit of the PDH?

A) E1
B) E2
C) E3
D) E4
E) E5

Question 38

Which of the following functions as a "flexible swinging arm" when it transfers the reaction intermediate from one active site to the next?

A) FAD
B) NAD+
C) lipoamide
D) thiamine pyrophosphate
E) coenzyme A

Question 39

In addition to PDH, what other enzymes are key regulatory sites in the citric acid cycle?

A) isocitrate dehydrogenase
B) ɑ-ketoglutarate dehydrogenase
C) citrate synthase (in bacteria)
D) A and B
E) A, B, and C

Question 40

Identify the coenzyme, and its vitamin precursor, that accepts electrons to reoxidize lipoamide in PDH.

Question 41

How are the three active sites of PDH linked?

Question 42

If NADH levels are high, what is the fate of acetyl CoA?

Question 43

The formation of acetyl CoA limits the cell's use of it to which two fates?

Question 44

What are the two advantages that are derived from the coordinated actions of the three enzymes in the PDH complex?

Question 45

What is the key means of regulation of PDH?