Which force is related to the membrane potential and is applicable only to ions?

• A. Chemical force
• B. Electrical force
• C. Osmotic force
• D. Mechanical force

Answer: (B)

The force related to the membrane potential that is applicable only to ions is the electrical force. This force arises from the difference in charge across a membrane and is a critical component in the movement of ions.

When there is a difference in ion concentration across a membrane, such as a higher concentration of positively charged ions inside or outside the cell, there will be an electrical potential established, which influences the movement of those ions. This potential can either attract or repel ions depending on their charge relative to the charge of the membrane. The electrical force directly impacts how ions move through ion channels in response to changes in membrane potential, which is crucial for various physiological processes, including nerve impulse transmission and muscle contraction.

In contrast, the other forces listed do not pertain specifically to the aspects of electrical charge and membrane potential in the context of ion movement. The chemical force relates to the concentration gradients and the tendency of ions to move from areas of high concentration to low concentration, while osmotic force involves the movement of water and solutes across semipermeable membranes due to osmotic gradients. Mechanical force refers to physical pressure and does not pertain to membrane potential or ionic movement directly. Thus, the electrical force is the key concept that connects membrane potential with the behavior