Question

Which option is correct for the correctly matched groups for the column I, column II and column III.

Column I	Column II	Column III
a. Resting membrane potential	(i) $N{a}^{+}$ channel get open	(e) $N{a}^{+}$ and $K^{+}$ pumps are responsible for it
b. Action potential	(ii)$N{a}^{+}$ channel is closed	(f) Last for very short time
c. Depolarisation	(iii) $N{a}^{+}$ more on outer side of membrane	(g) $K^{+}$ ions move on outerside
d. Repolarisation	(iv) $N{a}^{+}$ are more on inner side of membrane	(h) Positive charge on inner side of membrane

• A. (a-iii-e) (b-iv-f) (c-i-h) (d-ii-g)
• B. (a-ii-h) (b-i-g) (c-iii-e) (d-iv-f)
• C. (a-iv-f) (biiie) (c-i-e) (d-i-h)
• D. (a-iv-e) (b-iii-f) (c-ii-g) (d-i-g)

Answer 1

The correct option is A (a-iii-e) (b-iv-f) (c-i-h) (d-ii-g)

Resting membrane potential across an animal cell's plasma membrane, potassium (and sodium) gradients are established by the Na+/K+-ATPase (sodium-potassium pump) which transports 2 potassium ions inside and 3 sodium ions outside at the cost of 1 ATP molecule.

Action potential results in the movement of sodium ion more on the inner side of membrane and lasts for a short time.

Depolarization of membrane leads to movement of sodium ions inside the axon membrane and that of potassium ions outside the membrane via ATP energized pump to make the inside of axon positively charged.

As potassium ions exit the cell, this is going to make the inside of the cell less positive and more negative. This causes a repolarization.

Thus, the correct answer is option A.