Question

A resting nerve fiber is polarized because: a) the concentration of Na+ and K+ ions is higher on the inside of the cell membrane b) Na+ and K+ ions is higher outside the cell membrane c) Na+ is higher on the inside and K+ is higher on the outside d) Na+ is higher on the outside and K+ is higher on the inside.

Answer 1

A resting nerve fiber is polarized because the concentration of Na+ (sodium) ions is higher outside the cell membrane, while the concentration of K+ (potassium) ions is higher on the inside, establishing a negative resting membrane potential.

Step-by-step explanation:

A resting nerve fiber is polarized due to the differential distribution of Na+ (sodium) and K+ (potassium) ions across its cell membrane. This polarization is reflected by a resting membrane potential, typically around -70 millivolts (mV), where the inside of the cell is negatively charged relative to the outside. Resting membrane potential is crucial in maintaining the polarized state of the neuron.

The correct answer to the question is that: d) Na+ is higher on the outside and K+ is higher on the inside. The sodium-potassium pump plays an essential role in establishing this ion distribution by actively transporting 3 Na+ ions out of the cell and 2 K+ ions into the cell against their concentration gradients, thereby creating a net negative charge inside the cell.

During periods when the neuron is not transmitting a signal, it remains at this resting potential due to the selectively permeable membrane that allows K+ to move more freely than Na+, contributing further to the net negative charge inside the neuron.

Answer 2

Na+ is higher on the outside and K+ is higher on the inside. (Ans. D)

Step-by-step explanation:

Polarization is established by maintain the concentrations of Na+ is higher on the outside and K+ is higher on the inside. An amount of K+ and Na+ is always get out across the membrane with the help of leakage channels, but Na+/K+ pump which is present on the membrane helping in to restore the ions to the suitable side.

The resting nerve fiber (polarized nerve) is showing difference in permeability of the both ions. It is more permeable in nature to K+ ion than Na+ ion.