A large number of chemical reaction occur every moment in a cell to keep it. In the living state, The rate if chemical reaction normally depends upon the solubility . nature and density of reactions as well as well as upon the conditions of PH Pressure temperature etc. Of the medium in the laboratory we often use heat as an activation energy to accelerate chemical reactions.
Another way to accelerate reactions is to use certain chemicals called catalysts. Certain metals and compounds are used to accelerate nonbiological reactions living systems are compounds mainly of organic compounds which are less reactive than inorganic compounds .Metabolic reactions therefore cannot occur or proceed at required rates without being activated or accelerated i,e, mediated by biological catalysis.