Equilibrium - when molecules of a substance are spread out evenly through a space. Perfume - diffuses through the air. Osmosis - passive transport of water through a cell membrane by diffusion. Equilibrium - number of water molecules is the same inside the cell and outside the cell. B. Active transport - when materials require energy to move through the cell membrane.
Molecules are too large to move freely through the membrane.
Each carrier molecule helps to move only one kind of molecule through. Example - glucose molecules need a protein carrier molecule 2. Exocytosis - materials move out of the cell by the same process. Wastes from vacuoles. B. Cellular Respiration - process by which food is broken down in the cell to release energy.