CVS Practice Test 2025 – The All-In-One Guide to Exam Success!

Ion pumps are crucial for maintaining the membrane potential of cells by regulating the concentration of ions across the cell membrane. They achieve this by actively transporting ions such as sodium, potassium, calcium, and chloride, often against their concentration gradients. This active transport requires energy, typically derived from ATP, and ensures that specific ions are concentrated inside or outside the cell at varying levels.

For instance, the sodium-potassium pump is a well-known ion pump that moves sodium ions out of the cell and potassium ions into the cell. This action creates a gradient where the inside of the cell is more negative compared to the outside, contributing significantly to the resting membrane potential. The differential distribution of ions establishes a voltage difference across the membrane, which is essential for various cellular functions, including electrical signaling in neurons and muscle contraction.

Other options do not accurately pertain to the primary role of ion pumps in relation to membrane potentials. For example, while generating ATP is vital for cellular energy, it is not a direct function of ion pumps. Similarly, controlling cell shape and increasing membrane thickness are roles more associated with cytoskeletal components and membrane composition rather than the direct function of ion pumps.