Which causes the rapid change in the resting membrane potential ...

[ENagel]

Which causes the rapid change in the resting membrane potential that initiates an action poten-tial?
 
  a. Potassium gates open, and potassium rushes into the cell, changing the mem-brane potential from negative to positive.
  b. Sodium gates open, and sodium rushes into the cell, changing the membrane po-tential from negative to positive.
  c. Sodium gates close, allowing potassium into the cell to change the membrane po-tential from positive to negative.
  d. Potassium gates close, allowing sodium into the cell to change the membrane po-tential from positive to negative.

Question 2

How are potassium and sodium transported across plasma membranes?
 
  a. By passive electrolyte channels
  b. By coupled channels
  c. By adenosine triphosphate enzyme (ATPase)
  d. By diffusion

[ririgirl15]

Answer to Question 1

ANS: B
When the threshold is reached, the cell will continue to depolarize with no further stimulation. The sodium gates open, and sodium rushes into the cell, causing the membrane potential to re-duce to zero and then become positive (depolarization). Sodium is involved in creating the action potential, not potassium. The sodium gate and channel must be open, not closed. The action po-tential is not affected by a change in the potassium gate.

Answer to Question 2

ANS: C
The transporter protein ATPase is directly related to sodium and potassium transport via active transport. Electrolyte movements require energy and do not move passively, nor are they trans-ported by diffusion. Enzymes, not electrolytes, are passed via coupled channels.

[ENagel]

Thank you

[ririgirl15]

No problemo