Unit 7 Insulin Secretion Action

Question 1

What happens to glucose metabolism in insulin-deficient states?
a) Glucose is rapidly taken up by cells
b) Glucose oxidation increases
c) Glucose is stored as glycogen
d) Cells cannot uptake glucose efficiently; catabolism predominates

Answer 1

d) Cells cannot uptake glucose efficiently; catabolism predominates

Explanation: Without insulin, tissues like muscle and fat can’t import glucose, so the body shifts to fat and protein catabolism.

Question 2

What triggers insulin secretion from pancreatic beta cells?
a) Low blood glucose
b) High blood glucose, amino acids, GLP-1, parasympathetic input
c) Sympathetic stimulation only
d) Low amino acid levels

Answer 2

b) High blood glucose, amino acids, GLP-1, parasympathetic input

Explanation: Beta cells respond to nutrient signals and parasympathetic activation to promote insulin release.

Question 3

What type of glucose transporter is found on beta cells and hepatocytes?
a) GLUT1
b) GLUT2
c) GLUT3
d) GLUT4

Answer 3

b) GLUT2

Explanation: GLUT2 allows glucose to enter beta cells for monitoring and liver cells for storage/metabolism.

Question 4

How does insulin promote glucose uptake in muscle and fat?
a) Inserts GLUT4 transporters into the membrane
b) Stimulates glycogen breakdown
c) Increases GLUT2 expression
d) Activates sodium-glucose cotransporters

Answer 4

a) Inserts GLUT4 transporters into the membrane

Explanation: Insulin signaling mobilizes GLUT4 to the cell membrane in adipose and muscle, allowing glucose entry.

Question 5

What are insulin’s major anabolic effects?
a) Inhibits glycolysis and lipogenesis
b) Stimulates glycogenolysis and proteolysis
c) Promotes glycolysis, glycogenesis, lipogenesis, and protein synthesis
d) Enhances ketogenesis

Answer 5

c) Promotes glycolysis, glycogenesis, lipogenesis, and protein synthesis

Explanation: Insulin favors nutrient storage and use in anabolic pathways.