Diffusion: Net movement of particles from higher concentration to lower concentration.
Example: Oxygen and glucose molecules moving into cells.
Recommended to review previous videos on diffusion for better understanding.
Osmosis
Osmosis is a special case of diffusion.
Definition: Net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
Understanding Water Concentration
Water Concentration: Amount of water compared to solutes (dissolved molecules like sugars or salts).
Solutes are the molecules dissolved in water.
Example:
Two beakers each with the same amount of water represented by blue particles.
Left beaker: 1 particle of solute.
Right beaker: 3 particles of solute.
Right beaker has higher solute concentration and lower water concentration.
Left beaker has lower solute concentration and higher water concentration.
Key point: Concentration is determined by the proportion of water to solutes, not the volume of water.
Application to Cells
Cell Membrane: Acts as a partially permeable membrane.
Inside the cell: Contains many water and solute particles.
Outside the cell: Nearly pure water with a few solute particles.
Higher water concentration outside due to fewer solutes.
Water molecules will osmotically move into the cell from outside.
Osmosis: Water moves from a region of higher water concentration (outside) to lower water concentration (inside).
Additional Resources
Learning platform available for watching videos, practicing questions, and tracking progress in sciences and maths.
Platform is free and accessible via the provided links.