Give two Cellular Processes Enabled by Selective Permeability?

Selective permeability allows the cell membrane to control what enters and exits the cell. Two major processes enabled by this are diffusion and active transport. Diffusion is the passive movement of molecules from an area of higher concentration to lower concentration. For example, oxygen and carbon dioxide easily pass through the membrane to maintain essential gas exchange. 

This process doesn’t require energy. Active transport, on the other hand, uses energy (ATP) to move substances against their concentration gradient. For instance, the sodium-potassium pump in nerve cells maintains electrical balance by exchanging sodium and potassium ions. These processes ensure that cells take in nutrients, remove waste, and maintain internal balance despite changing external environments. Without selective permeability, harmful substances could flood the cell, and vital ions or molecules could leak out, disrupting metabolism and survival. Thus, selective permeability is essential for cell function and life itself.