Question

Being continuously open allows ion channels to maintain a membrane potential of zero since:

a) there is a constant flow of Na in and out of the cell
b) there is a constant flow of K in and out of the cell
c)movement of Cl in and K out of the cell
d) Ion channels are not continuously open
e) Na, K, and Cl can diffuse across the membrane without the need of passing through an ion channel

Answer 1

Ion channels are not continuously open; they respond to various stimuli and help maintain the resting membrane potential, which is not zero but around -70 mV in neurons.

Step-by-step explanation:

Being continuously open allows ion channels to maintain a membrane potential of zero is not a correct statement. Ion channels are not continuously open; they can be gated and respond to different stimuli by opening or closing. The cell membrane's semipermeable nature, along with the selective permeability of ion channels, contributes to the maintenance of the resting membrane potential, which is commonly around -70 mV for a neuron at rest. It is the diffusion of K+ (potassium ions) and Cl- (chloride ions), and the impermeability to Na+ (sodium ions) that results in the creation of this potential difference across the membrane, not a constant flow of ions in and out of the cell.

Sodium-potassium pumps and leakage channels also play a crucial role in maintaining the resting potential by regulating the concentration of Na+ and K+ across the membrane. Therefore, option (d) 'Ion channels are not continuously open' would be the correct answer.