BIO 175 Passive Transport Explained

In this lecture, we’ll explore essential concepts that explain how substances move across the plasma membrane without using cellular energy. We break down diffusion, osmosis, facilitated diffusion, tonicity, and the fluid mosaic model, helping you master this key unit in cell physiology. Topics Covered: What is membrane permeability? Types of permeability: impermeable, freely permeable, selectively permeable The plasma membrane & fluid mosaic model Simple diffusion and facilitated diffusion Osmosis and osmotic pressure Tonicity: isotonic, hypotonic, and hypertonic solutions The role of passive transport in homeostasis Clinical examples (e.g., hypernatremia, hyponatremia, filtration)