Membrane Transport

Membrane transport refers to the ways substances move in and out of cells through their outer membranes. Cells are surrounded by a lipid bilayer, which is selectively permeable, allowing certain molecules to pass while blocking others. This transport can occur actively, using energy to move substances against their concentration gradient, or passively, where molecules flow naturally from areas of higher concentration to lower concentration. Common processes include diffusion, osmosis (water movement), and facilitated transport (using specific proteins). These mechanisms are essential for maintaining cellular functions, nutrient uptake, and waste removal.