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 is equal causing the membrane potential to equal zero
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 and therefore maintain a membrane
potential of zero

Answer 1

Ion channels enable the diffusion of specific ions across the cell membrane, contributing to the generation and regulation of the resting membrane potential. The movement of ions such as potassium and chloride creates a charge difference, while sodium ion inflow during depolarization shifts the potential towards zero.

Step-by-step explanation:

The question relates to the cellular mechanism by which ion channels contribute to the establishment and maintenance of membrane potential. Ion channels are specific protein complexes that allow ions to move across the cell membrane. In the case of a neuron in its resting state, potassium (K+) and chloride (Cl-) ions diffuse through their respective channels, creating a charge difference across the membrane, known as the resting membrane potential.

The resting membrane potential is typically around -70 mV, with the inside of the neuron being more negative than the outside. Ion channels play a crucial role in manipulating this potential, with some channels allowing diffusion of ions without the need for stimuli (non-gated), and others being responsive to various signals (gated). When Na+ channels open, Na+ rushes into the cell due to both a concentration gradient and electrical gradient, a process that can lead to depolarization, thus shifting the membrane potential toward zero.