The substrate and the active site both need to fit together perfectly in order for the enzyme to work properly. If their shape is changed, typically through heat or a change in pH, the enzyme will not work.
<span>One process wherein diffusion is important is the concentration of salt within a cell. When the salt levels are too high within the cell, salt molecules are moving via diffusion to a region of lower concentration. Another process is the movement of carbon dioxide in plant cells, where CO2 moves from regions of high concentration to regions of low concentration.</span>
