Answer to Question #43281 in Biology for dinisha

Question

an action potential is an electrochemical change because it consist of polarity changes brought about by the movement of
A. Na^+ and Ca^+
B. K^+ and Ca^+
C. Na^+ and Ag^2+
D. Na^+ and Hg^+
E. Na^+ and K^+

Answer 1

When a nerve cell is stimulated, ion gates in the plasma membrane open and Na⁺ instantly diffuses down its concentration gradient into the cell. The inside of the plasma membrane briefly becomes positive. Immediately, Na⁺ gates close and K⁺ gates open. K⁺ diffuses down its concentration gradient from the cell. The loss of positive potassium ions from the cell turns the inside of the membrane negative again. This quick up-and-down voltage shift, from the negative resting membrane potential (RMP)
to a positive value and then back to a negative value again, is called an action potential. The RMP is a stable voltage seen in a “waiting” cell, whereas the action potential is a quickly fluctuating voltage seen in an active, stimulated cell. Thus, the correct answer is E