Glycolysis Metabolism

Question 1

During glycolysis, isomerization occurs
during which of the following reactions.

a. Fructose 1,6 bisphosphate ->
dihydroxyacetone phosphate and
glyceraldehyde 3-phosphate
b. Fructose 6 phosphate ->
fructose 1,6 bisphosphate
c. Glucose 6- phosphate ->
fructose 6- phosphate
d. Glucose -> glucose 6-
phosphate

Answer 1

c. Glucose 6- phosphate ->
fructose 6- phosphate

Question 2

Transfer of a high-energy phosphoryl group
to ADP, resulting in ATP occurs when the
following conversion takesplace.

a. 1,3 Bisphosphoglycerate -> 3-
phosphoglycerate
b. Phosphoenolpyruvate (PEP) ->
pyruvate
c. 3-Phosphoglycerate -> 2-
phosphoglycerate
d. Both a and b
e. None of the above

Answer 2

d. Both a and b

Question 3

An intramolecular phosphoryl- group
transfer occurs when the following
conversion takesplace.

a. 2-Phosphoglycerate is converted to
phosphoenolpyruvate
b. 1,3 bisphosphoglycerate is converted
to 3-phosphoglycerate
c. Both a and b
d. None of the above

Answer 3

d. None of the above

Question 4

In some Diabetic patients, glucose
increases disproportionately and is
unresponsive to an insulin challenge; under these conditions, how would one’s liver normally respond?

a. Phosphorylating glucose for entry
into the glycolytic pathway
b. Saturating glucokinase with glucose
c. Phosphorylating glucose for entry
into the glycogen synthesis pathways
d. a and b only
e. a and c only

Answer 4

e. a and c only

Question 5

Glucose 6-phosphate
allosterically inhibits
a. Hexokinase I
b. Glucokinase
c. Hexokinase II
d. All of the above
e. a and c only

Answer 5

e. a and c only

Question 6

Phospholfructokinase I deficiency results in:
a. An overproduction of Fructose 6-
phosphate
b. An overproduction of Fructose 1,6
bisphosphate
c. Fructose 1,6 bisphosphate
deficiency
d. a and c only
e. All of the above

Answer 6

d. a and c only

Question 7

Glyceraldehyde 3-phosphate
dehydrogenase causes the following
conversion.

a. The reduction and phosphorylation of
glyceraldehyde 3-phosphate to produce
1,3 bisphosphoglycerate
b. The oxidation of a molecule of
NAD+ to NADH
c. Neither a nor b
d. Both a and b

Answer 7

d. Both a and b

Question 8

Which of the following enzymatic reactions
is/are control points for glycolysis:
a. Glucose 6-phosphate isomerase
b. Aldolase
c. Both a and b
d. Neither a nor b

Answer 8

d. Neither a nor b

Question 9

Substrate level phosphorylation describes
the following conversion.

a. Describes the conversion of ADP
into ATP with the addition of inorganic
phosphate every place throughout the
cell
b. Describes the formation of ADP by
phosphoryl group transfer from 1,3
bisphosphoglycerate
c. None of the above
d. Both a and b

Answer 9

c. None of the above

Question 10

Mutase catalized reactions are described
in one of the following.

a. Polymerases which catalyze
phosphoryl group transfers
b. Isomerases which catalyze the transfer
of phosphoryl groups from one part of a
substrate molecule to another
c. Forming intermediate free
phosphate (Pi)
d. All of the above

Answer 10

b. Isomerases which catalyze the transfer
of phosphoryl groups from one part of a
substrate molecule to another

Question 11

Which amino acid’s residue plays a role in
the phosphoglycerate mutase reaction in
glycolysis for muscle and yeast?
a. Leucine
b. Lysine
c. Alanine
d. Histidine

Answer 11

d. Histidine

Question 12

Which of the following mutases catalyze
the formation of a 2,3 BPG intermediate?
a. Muscle phosphoglycerate
mutases
b. Plant phosphoglycerate
mutases
c. Yeast phosphoglycerate
mutases
d. a and c only
e. All of the above

Answer 12

d. a and c only

Question 13

Which of the following is not regulated in
glycolysis?

a. Pyruvate kinase
b. Phosphoglycerate kinase
c. Hexokinase
d. PFK-1

Answer 13

b. Phosphoglycerate kinase

Question 14

Transfer of the phosphoryl group from PEP
to ADP is an example of
a. A mutase reaction
b. Isomerization
c. A dehydrogenase
d. None of the above

Answer 14

d. None of the above

Question 15

Which of the following is not a
metabolically irreversible enzymatic
reaction of glycolysis?
a. Pyruvate kinase reaction
b. PFK-1 reaction
c. Hexokinase/Glucokinase
reaction
d. None of the above

Answer 15

d. None of the above

Question 16

Two molecules of ATP are produced per
glucose during the hexose stage of
glycolysis.
a. True
b. False

Answer 16

b. False

Question 17

In glycolysis, there is a net yield of 2
molecules of ATP per molecule of
glucose.
a. True
b. False

Answer 17

a. True

Question 18

Isozymes are different proteins from one
species which catalyze different
chemical reactions.
a. True
b. False

Answer 18

b. False

Question 19

The reaction catalyzed by PFK-1 is
metabolically reversible.
a. True
b. False

Answer 19

b. False

Question 20

Glucose is the only hexose which can enter
the glycolytic pathway.
a. True
b. False

Answer 20

b. False

Question 21

Glyceraldehyde 3-phosphate and
dihydroxyacetone phosphate are
substrates in an oxidation and
phosphorylation reaction, which yields a
high energy mixed anhydride.
a. True
b. False

Answer 21

b. False

Question 22

Triose phosphate isomerase is not
diffusion controlled.
a. True
b. False

Answer 22

b. False

Question 23

Under aerobic conditions yeast cells
convert pyruvate to ethanol and carbon
dioxide.
a. True
b. False

Answer 23

b. False

Question 24

Mammals can convert pyruvate to either
ethanol or lactate depending on the
availability of oxygen.
a. True
b. False

Answer 24

b. False

Question 25

Lactic acid produced by certain bacteria is used to curdle milk during cheesemaking. a. True b. False

Answer 25

a. True

Question 26

All ten steps of the glycolytic pathway must have negative free energies for glycolysis to proceed. a. True b. False

Answer 26

b. False

Question 27

Glucose is the only monosaccharide that can enter the glycolytic pathway at the first step. All other monosaccharides enter at a subsequent step in the pathway. a. True b. False

Answer 27

b. False

Question 28

The conversion of pyruvate to ethanol also causes the--------- a. oxidation of NADH b. production of ADP c. consumption of O2 d. generation of an ion gradient across mitochondrial membranes

Answer 28

a. oxidation of NADH

Question 29

Compared to pyruvate, the carbon atoms in lactate ------ a. are more reduced b. are more oxidized c. are equally as oxidized d. carry more charge

Answer 29

a. are more reduced

Question 30

The enzyme that catalyzes the conversion of pyruvate to lactate is .---------- a. lactate reductase b. pyruvate kinase c. lactoenolpyruvate d. lactate dehydrogenase

Answer 30

d. lactate dehydrogenase

Question 31

What is the function of pyruvate decarboxylase? a. The conversion of pyruvate to carbon dioxide and acetaldehyde. b. To completely oxidize pyruvate to three molecules of carbon dioxide. c. To convert phosphoenolpyruvate to pyruvate. d. To regulate PFK-1.

Answer 31

a. The conversion of pyruvate to carbon dioxide and acetaldehyde.

Question 32

Which applies to fructose 1,6- bisphosphate? a. inhibitor of pyruvate kinase b. product of PFK-1 catalyzed step in glycolysis c. isomer of glucose 1,6- bisphosphate d. all of the above

Answer 32

d. all of the above

Question 33

How does the number of molecules of ATP produced compare for conversion of one molecule of either glucose or fructose to pyruvate? a. fructose produces one less ATP than glucose b. fructose produces the same number of ATP's c. fructose produces one more ATP than glucose d. fructose produces twice the number of ATP compared to glucose

Answer 33

b. fructose produces the same number of ATP's

Question 34

Enzymes which catalyze the same reaction are called . a. isozymes b. complementary enzymes c. cofactors d. catalytes

Answer 34

a. isozymes

Question 35

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation? a. to keep glucose inside the cell b. to form a high-energy compound c. to activate PFK-1 d. to prevent mutarotation

Answer 35

a. to keep glucose inside the cell

Question 36

Which substance causes muscles to ache during strenuous exercise? a. pyruvic acid b. lactose dehydrogenase c. lactate ion d. lactic acid

Answer 36

d. lactic acid