Chapter 4: Chemical Reactions

Chemical reactions are the rearrangement of matter. For example, we have discussed the reaction between carbon dioxide and water to form carbonic acid. The atoms within the starting molecules are rearranged by breaking the chemical bonds between atoms and molecules, then making new chemical bonds between the resulting atoms and molecules. The input molecules into a chemical reaction are called reactants and the output molecules are called products. In cells, most chemical reactions are performed by proteins called enzymes.