Comparing diffusion , osmosis and active transport

• Substances move into and out of cells in animals, plants and microorganisms by three processes: diffusion, osmosis and active transport.
• In diffusion, substances move from a high to a low concentration down a concentration gradient.
• Examples of substances moved in diffusion include carbon dioxide, oxygen, water, food substances, wastes such as urea.
• In osmosis, water moves from a high to a low concentration across a partially permeable membrane and down a concentration gradient.
• Examples of substances moved in osmosis include water.
• In active transport, substances move against a concentration gradient.
• Examples of substances moved in active transport include mineral ions into plant roots and glucose from the gut into intestinal cells, from where it moves into the blood.