What is Metabolism ?
Metabolism is usually defined as the sum of the chemical processes required to sustain life. These processes, called metabolic pathways, are catalyzed by enzymes. The chemical pathways proceed in a sequence that provides that the product of one reaction can act as the substrate for the next.
Energy for metabolism is stored in molecules such as ATP, NAD, and FAD. These molecules are produced and used in the process of cellular respiration, which breaks down glucose. Glucose is formed through the process of photosynthesis in plants, which convert light energy from the sun into chemical energy available for metabolic processes.