Cell Metabolism: Types of Metabolic Reactions

General Concepts

Chemical reactions involve the conversion of reactants (A + B) into products (C + D). The reaction can go in either direction so that the products (C + D) become the reactants and the reactants (A + B) the products.  By convention the reactants are written on the left side and the products on the right. A + B ® C + D.  However, as already noted, the reaction can go in either direction. If more products (C + D) are being created the reaction is said to be going forward. If more reactants (A + B) are being produced the reaction is going in reverse. Forward and reverse therefore refers to the net reaction that results from the sum of all individual reactions.      Reactions can either be: Catabolic - When the products are smaller molecules than the reactants. e.g. proteins  ® amino acids; or Anabolic - When the products are larger molecules than the reactants. e.g. amino acids ®  proteins