Diffusion defined is the movement of particles through a partially permeable membrane from an area of higher concentration to an area of lower concentration.
Diffusion is important as it allows substances to go into the cell to use for energy, growth and many other important processes that occur to support the cell. It also allows substances to leave the cell to get rid of waste products which is no longer required in the cells.
Take for instance, animals, a category that includes humans. We need diffusion in order to allow gas exchange to occur which aids us to respire. In the process of respiration, oxygen (O2) is taken in (breathed in) and carbon dioxide (CO2) is released. In our digestive system, we also need diffusion to absorb water in the large intestine.
And in plants, diffusion is also required for photosynthesis (a type of gas exchange in plants). Throughout the process of photosynthesis, carbon dioxide is taken in, and oxygen is released. Another example where plants use diffusion is in transpiration, which is the diffusion of water from a plant’s surface.