When the blood glucose concentration is low, the pancreassecretes glucagon to signal the liver to produce glucose andglucose-1-phosphate. Which metabolic steps are involved in thisbiosignaling pathway? I. Inactivation of glycogen synthase via phosphorylation by proteinkinase A II. Activation of glycogen synthase via phosphorylation by proteinkinase A III. Activation of phosphofructokinase-2 via phosphorylation byprotein kinase A IV. Activation of fructose-2,6-bisphosphatase via phosphorylation byprotein kinase A V. Activation of phosphofructokinase-1 byfructose-2,6-bisphosphate VI. Inhibition of fructose-1,6-bisphosphatase byfructose-2,6-bisphosphate VII. Inactivation of pyruvate kinase via phosphorylation by proteinkinase A A. I, IV, and VII. B. II C. I and IV. D. I, III, V, VI, and VII.

Which biochemical steps are involved in the glucagon-triggeredactivation of gluconeogenesis? I. Activation of fructose-2,6-bisphosphatase via phosphorylation byprotein kinase A II. Inactivation of fructose-2,6-bisphosphatase via phosphorylationby protein kinase A III. Activation of phospholipase C IV. Inactivation of phospholipase C V. Release of calcium VI. Sequestration of calcium VII. Phosphorylation of FoxO1 VIII. Dephosphorylation of FoxO1 IX. Increased expression of PEP carboxykinase X. Phosphorylation of PEP carboxykinase XI. Formation of additional PEP, which is a glycolyticintermediate XII. Degradation of PEP, which is a glycolytic intermediate A. I, III, V, VII, X, and XI. B. II, III, V, VII, IX, and XI. C. I, III, VI, VII, IX, and XII. D. I, III, V, VII, IX, and XI.

When the blood glucose concentration is high, the level of cAMPin the liver decreases and glycolytic flux increases. Whichbiochemical steps occur under this condition? I. Protein kinase A is activated. II. Protein kinase A is not activated. III. Phosphofructokinase-2 is activated via phosphorylation byprotein kinase A. IV. Phosphofructokinase-2 is activated due to the lack ofphosphorylation by protein kinase A. V. Fructose-2,6-bisphosphatase is activated via phosphorylation byprotein kinase A. VI. Fructose-2,6-bisphosphatase is activated due to the lack ofphosphorylation by protein kinase A. VII. Phosphofructokinase-1 is activated byfructose-2,6-bisphosphate. VIII. Phosphofructokinase-1 is inhibited byfructose-2,6-bisphosphate. IX. Fructose-1,6-bisphosphatase is activated byfructose-2,6-bisphosphate. X. Fructose-1,6-bisphosphatase is inhibited byfructose-2,6-bisphosphate. A. II, IV, VIII, and IX. B. II, IV, VII, and X. C. I, III, VII, and X. D. II and V.

After glucagon stimulates glucose production via glycogenolysisand/or gluconeogenesis in a liver cell, which steps are required totransport glucose to other cells in the body? A. Glucose is transported to other cells by the carrier proteinGLUT-1. B. Glucose-6-phosphate is converted to glucose by GLUT-1. C. Glucose cannot leave the liver cell. D. Glucose exits the liver cell via GLUT-1 and enters thebloodstream.

In certain smooth muscles, glucagon increases the amount ofglucose available for glycolysis; under this condition, whichenzyme is required to convert glucose-1-phosphate into a glycolyticintermediate? A. No enzyme is needed for this conversion. B. G6Pase. C. Glucokinase (or hexokinase). D. Phosphoglucomutase.