3. Pancreatic beta cells use changes in K + and Ca 2+ permeabilities to facilita
ID: 3477616 • Letter: 3
Question
3. Pancreatic beta cells use changes in K+ and Ca2+ permeabilities to facilitate the release of insulin. When glucose moves into beta cells via GLUT2, glucose is used in glycolysis for immediate energy. The ATP produced binds to an ATP-sensitive K+ channel and closes it. a. When the K+ channel closes, what happens to Vm? Circle all correct. (3 pts)
More negative depolarizes increases
More positive hyperpolarizes decreases
b. Circle all that accurately describe this change in potential. (6 pts)
regenerates requires a minimum voltage to initiate
variable amplitude can summate
Vm approaches EK+ involves ligand-gated channels
c. Beta cells have voltage-gated Ca2+ channels that are activated by the change in Vm described above. When these channels open, does Ca2+ move into or out of the cell? Circle: into out of (4 pts)
d. What is/are the force(s) driving Ca2+ movement?
(4 pts)
e. Assuming Ca2+ channels remain open, at what point does Ca2+ stop moving? Explain in 15 words. (4 pts)
Explanation / Answer
A) When the ATP binds with the ATP sensitive K+ channel, it will cause the Membrane potential to depolarize that allowing Ca+ release of insulin in maintaining the glucose matabolism. The answer is Depolarize and more negative.
B) Involves ligand gated channels and Vm approaches EK+
C) When the Ca2+ are activated the Ca2+ moved out of the cell thus release the insulin from Beta cells of pancreas in maintaining the glucose hoemostasis.
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