- Von Gierke's disease results from a deficiency in glucose-6-phosphatase.
Which of the following best depicts what the ramifications of
this disease might be?
Glucose
levels increase in liver, kidney, and intestinal epithelium.
Glycogen
levels increase in liver, kidney, and intestinal epithelium.
Glucose
levels increase in the brain.
Glycogen
levels increase in the brain.
- Which of the following explains why 50% more energy in the
form of ATP is obtained from glycolysis when starting with glycogen
than when starting with glucose?
Hexokinase
adds ATP to glucose-6-phosphate to form glucose-1,6-bisphosphate.
Hexokinase
adds ATP to glucose-6-phosphate to form fructose-1,6-bisphosphate.
Phosphorylase
cleaves the glucose-6-phosphate monomers from glycogen branches.
Phosphorylase
uses inorganic phosphate directly to produce glucose-6-phosphate.
- Which of the following explains how epinephrine is able to
activate phosphorylase and simultaneously inhibit glycogen synthase?
Epinephrine
binds to glycogen synthetase but not to phosphorylase.
Epinephrine
binds to phosphorylase but not to glycogen synthetase.
Protein
kinase A activates phosphorylase and inhibits glycogen synthetase.
Phosphoprotein
phosphatase activates phosphorylase and inhibits glycogen synthetase.
- Which of the following best describes the role of a membrane
in oxidative phosphorylation?
An
impermeable barrier to H+ allows the creation of a
proton motive force.
A
permeable barrier to H+ creates passive transport
and a proton motive force.
An
impermeable barrier to e- allows the creation of an
electron motive force.
A
permeable barrier to e- creates passive transport
and an electron motive force.
- Which of the following enzymes generate high-energy phosphate
at the substrate level?
phosphofructokinase
1
phosphoglycerate
kinase
lactate
dehydrogenase
aldolase
phosphoglyceromutase
- All of the following are required for the conversion of glucose
to acetyl-CoA in striated muscle EXCEPT which one?
the
action of lactate dehydrogenase (LDH)
the
action of phosphofructokinase 1 (PFK1)
phosphorylation
of glucose to glucose 6-phosphate
cleavage
of fructose 1,6-bisphosphate to triose phosphates
NAD
- Administration of primaquine to humans with a deficiency
of glucose 6-phosphate dehydrogenase produces anemia. The best
reason given below for this anemia is:
inability
to decompose peroxide via glutathione peroxidase because of lack
of a physiological reductant for glutathione.
excess
ATP production in the absence of an alternate pathway for utilization
of glucose-6-phosphate.
lower
than normal NADH production rates.
inhibition
of glycolysis by primaquine.
inability
to produce nucleotides and thus limiting DNA production and causing
a slowing of erythrocyte production.
- All of the following occur in the hexose monophosphate pathway
for glucose metabolism, EXCEPT:
reduction
of NAD+.
formation
of C-7 sugar phosphates.
formation
of C-5 sugar phosphate precursor of nucleotides.
release
of C-1 of glucose as carbon dioxide.
reduction
of NADP+.
- During strenuous exercise, the NADH produced in the reaction
catalyzed by glyceraldehyde 3-phosphate dehydrogenase in skeletal
muscle has to be reoxidized in order for glycolysis to continue.
The primary enzyme involved in this reoxidation is:
malate
dehydrogenase.
lactate
dehydrogenase.
pyruvate
dehydrogenase.
isocitrate
dehydrogenase.
glucose
6-phosphate dehydrogenase.
- In oxidative phosphorylation, an uncoupling agent causes
which of the following?
both
respiration and phosphorylation to decrease
phosphorylation
to remain constant and respiration to decrease
respiration
to increase and phosphorylation to decrease
respiration
and phosphorylation to increase
the
P:O ratio to increase