Enzymes are regulated by more than the binding of small molecules. A second method that is used all the time by eucaryotic cells to regulate a protein's function is the covalent addition of a phosphate group to one of its amino acid side chains. These phosphorylation events can affect the protein in two important ways.
The appropriate response is Smooth muscles. Smooth muscle is found in the dividers of empty organs like your digestion tracts and stomach. They work naturally without you monitoring them. Smooth muscles are associated with many 'housekeeping' elements of the body. The strong dividers of your digestive organs contract to push nourishment through your body.
All living things are made up in cells?
