Question

Match the column I and column II and choose the correct option.
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{A.Synapse}& \text{I. Opening of sodium channels}\\ & \text{resulting in rapid influx of sodium}\\ & \text{and closing of sodium channels.}\\ \text{B.Repolarization phase}& \text{II. The electrical potential difference}\\ & \text{across the resting plasma membrane.}\\ \text{C. Resting Potential}& \text{III. The site of transmission of electric}\\ & \text{nerve impulses between two neurons.}\\ \text{D. Depolarization}& \text{IV. Opening of potassium channels}\\ & \text{and rushing out of potassium.}\end{array}$

• A. A-II, B-I, C- IV, D-III
• B. A-III, B- I, C- II, D- IV
• C. A-III, B-IV, C-II,D-I
• D. A-IV, B-II, C-I, D-III

Answer 1

The correct option is C A-III, B-IV, C-II,D-I

The synapse, also called the neuronal junction, is the site of transmission of electric nerve impulses between two neurons or between a neuron and a gland or muscle cell.
In the resting state, a neuronal cell membrane has a resting potential, i.e., the outer side is more positively charged than the inner side.
When a stimulus is applied at a site on the polarised membrane, the membrane at the site becomes freely permeable to $N{a}^{+}$ due to the opening of $N{a}^{+}$ channels. This leads to a rapid influx of $N{a}^{+}$ followed by the reversal of the polarity at that site; this is called depolarization.
Repolarization phase of the action potential is dependent on the opening of potassium channels which cause the efflux (moving out) of the potassium ions out of the neuron. This rapidly decrease the membrane potential, bringing it back towards its normal resting state.