a) Simple Diffusion: It occurs without the help of any protein molecule. Examples: The movement of water, oxygen, carbon dioxide, ethanol, and urea. b) Facilitated Diffusion: It is a selective process that occurs with the help of a transmembrane protein molecule. Facilitated diffusion can occur either through a channel protein or through a carrier protein. Examples: Transport of glucose, sodium ions, and potassium ions.
2) Osmosis
The spontaneous movement of water molecules from a region of low solute concentration to a region of high solute concentration through a semipermeable membrane. It is a selective process that allows only solvent molecules to pass while restricting the solutes. Examples: Taking of nutrients and minerals inside the cell and getting rid of its waste products.
