EXAM III Flashcards
The β cells of the pancreas secrete __________ in response to __________ glucose levels.
a) insulin, low
b) insulin, high
c) glucagon, low
d) glucagon, high
e) None of the above
b) insulin, high
Which of the following is (are) associated with cAMP binding to protein kinase A?
a) cAMP binds to the regulatory subunits
b) regulatory subunits dissociate from catalytic subunits
c) catalytic subunits phosphorylate multiple targets
d) All of the above
e) None of the above
d) All of the above
Consider the following metabolic reaction:
Succinyl-CoA + Acetoacetate → Acetoacetyl0CoA + Succinate ∆G^o’=-1.25 kJ/mol
This reaction is:
a.) Favorable under standard conditions
b.) Not favorable under standard conditions
c.) Always exergonic and can never proceed in the opposite direction
d.) Spontaneous as written when [succinate] and [acetoactyl-CoA] are high
e.) None of the above
a.) Favorable under standard conditions
If you are running away from a bear,
a) your muscle cells will be running glycolysis, and your liver cells will be running gluconeogenesis
b) your muscle cells will be running gluconeogenesis, and your liver cells will be running glycolysis
c) both your muscle cells and liver cells will be running glycolysis
d) both your muscle cells and liver cells will be running gluconeogenesis
a) your muscle cells will be running glycolysis, and your liver cells will be running gluconeogenesis
Increased levels of epinephrine in the blood will:
a) Activate cAMP production in liver and muscle cells
b) Stimulate glycogen synthesis
c) Inhibit glycolysis in the muscle cell
d) Stimulate gluconeogenesis in the muscle cell
e) Inhibit the formation of cAMP
a) Activate cAMP production in liver and muscle cells
The K_eq is 0.503 at 25ºC for the following reaction. What is the ∆G^o’ for this reaction?
D-Glucose-6-phosphate → D-Fructose-6-phosphate
a.) -1,700 J/mol
b.) -2,870 J/mol
c.) +143 J/mol
d.) +1.70 kJ/mol
e.) none of the above
d.) +1.70 kJ/mol
In skeletal muscle, the main purpose of fermentation of pyruvate to lactate is:
a) Remove toxic pyruvate from the cell
b) Regenerate NAD+ used during glycolysis
c) Provide a precursor for amino acid synthesis
d) Activate pyruvate for the citric acid cycle
e) prevent you from becoming intoxicated through ethanol fermentation
b) Regenerate NAD+ used during glycolysis
Which of the following metabolic conversions is considered to be the major control point of glycolysis?
a. ) Fructose-1,6-bisphosphate → dihydroxyacetone phosphate + glyceraldehyde-3-phosphate
b. ) Glucose → glucose-6-phosphate
c. ) 2-phosphoglycerate → phosphoenolpyruvate
d. ) fructose-6-phosphate → fructose-1,6-bisphosphate
e. ) pyruvate → lactate
d.) fructose-6-phosphate → fructose-1,6-bisphosphate
The metabolic fate(s) of glucose-6-phosphate include:
a) glycogen and glucose
b) Ribose-5-phosphate and acetyl-CoA
c) Both of the above
d) None of the above
c) Both of the above
During glycolysis, the steps between glucose and the formation of the triose phophates:
a. ) Consumes two ATP and two NADH molecules
b. ) Consume two ATP molecules
c. ) Product two ADP and two NAD^+ molecules
d. ) Produce two ATP and two NADH molecules
e. ) Consume two NADH molecules
b.) Consume two ATP molecules
In eukaryotes, the enzymes that catalyze the reactions of glycolysis are located in:
a) The cell nucleus
b) The endoplasmic reticulum
c) The mitochondria
d) The lysosomes
e) The cytosol
e) The cytosol
The hormone secreted by the pancreas under low blood sugar conditions is
a) insulin
b) glucagon
c) epinephrine
d) neuropeptide Y
e) jurisisawesomine
b) glucagon
Which of the following statements about glycogen and glucose metabolism in skeletal muscle is correct?
a) Glycogen is hydrolyzed to free glucose that can enter the glycolytic pathway
b) Glucose residues from glycogen yield a net of 3 ATP when converted to lactate in skeletal muscle
c) No nucleotide is required to convert glucose to glycogen
d) Phosphorylase is the only enzyme required to totally degrade glycogen to glucose-6-phosphate
e) ATP is directly required for the conversion of glycogen to glucose-1-phosphate
b) Glucose residues from glycogen yield a net of 3 ATP when converted to lactate in skeletal muscle
The enzyme catalyzing the reaction fructose-6-phosphate → fructose-1,6-bisphosphate
a. ) is allosterically activated by AMP
b. ) is allosterically inhibited by ATP
c. ) is activated by fructose-2,6-bisphosphate
d. ) A, B, and C
e. ) A and C
d.) A, B, and C
The carbons of galactose enter glycolysis at the level of
a) Glucose-6-phosphate
b) Fructose-6-phosphate
c) Dihydroxyacetone phosphate
d) 3-phosphoglycerate
a) Glucose-6-phosphate
