Learn: Diffusion and Osmosis

Welcome!Today we'll learn about diffusion and osmosis, two key processes related to movement across membranes. By the end, you'll understand how they work and why they're important for cells.

What is Diffusion?Diffusion is the movement of particles from a region of high concentration to a region of low concentration. It occurs down a concentration gradient and does not require energy. Oxygen and carbon dioxide move in and out of cells by diffusion.

What is Osmosis?Osmosis is the movement of water molecules across a selectively permeable membrane from a region of high water potential to a region of low water potential. Osmosis is vital for maintaining cell hydration and function.

Selective Permeable MembranesA selectively permeable membrane allows certain molecules to pass through while blocking others. For example, it lets water molecules move during osmosis but prevents larger molecules like proteins from passing through.

How Osmosis Affects CellsWater movement in osmosis can cause cells to gain or lose water. In a hypotonic solution (higher water potential outside), cells gain water and may swell. In a hypertonic solution (lower water potential outside), cells lose water and may shrink.

Real-World Example: Visking TubingVisking tubing acts as a model for a selectively permeable membrane. It allows small molecules like water to pass through but blocks larger molecules like starch. Scientists use it to study osmosis and diffusion.

Review Time!Great work! You've learned about diffusion, osmosis, and selectively permeable membranes. Let’s test your understanding with a few questions.

Final Review Question!Let’s check your understanding of osmosis one more time!

ConclusionFantastic effort today! You've learned about diffusion, osmosis, and their importance to cells. Keep practising these concepts to strengthen your understanding.