Differentiate osmosis from diffusion. Give an example to illustrate their difference.

Osmosis and diffusion are both passive transport processes, which means they do not require energy or input from the cell to occur. However, they differ in the types of molecules they transport and the reasons why these molecules move.

1. Diffusion: This is the process by which particles spread out from each other, or disperse. It occurs in both gases and liquids and involves the movement of particles from an area of high concentration to an area of low concentration. The driving force behind diffusion is the kinetic energy of particles, which causes them to move randomly. The end result of diffusion is a uniform distribution of particles. An example of diffusion is the way the smell of perfume disperses in a room. When you first spray it, the particles are highly concentrated in one area, but they soon spread out, or diffuse, throughout the room.

2. Osmosis: This is a special type of diffusion that involves the movement of water molecules across a semi-permeable membrane. In osmosis, water moves from an area of low solute concentration to an area of high solute concentration. The purpose of this movement is to equalize the concentration of the solute on both sides of the membrane. An example of osmosis is the process by which plants take up water from the soil. The soil has a higher concentration of water than the plant roots, so water moves into the roots by osmosis.

In summary, while both osmosis and diffusion involve the movement of particles from an area of high concentration to an area of low concentration, diffusion applies to all types of particles and does not require a membrane, while osmosis specifically involves the movement of water across a semi-permeable membrane.