How Does the Plasma Membrane Function as a Selective Barrier?
The plasma membrane's selective permeability is essential for cellular homeostasis. This is achieved through various mechanisms:
Passive Transport: Movement of molecules down their concentration gradient without energy expenditure, including diffusion and osmosis. Active Transport: Energy-dependent movement of molecules against their concentration gradient, often mediated by transport proteins like pumps. Facilitated Diffusion: Passive transport aided by specific membrane proteins. Endocytosis and Exocytosis: Processes for bulk transport of materials into and out of the cell, respectively.
