The process of respiration in plants involves using the sugars produced during photosynthesis plus oxygen to produce energy for plant growth. In many ways, respiration is the opposite of photosynthesis. In the natural environment, plants produce their own food to survive. Respiration is one of the fundamental processes that is carried out by living entities. All the energy that is required for life processes is obtained by the oxidation of some macromolecules derived from food. Autotrophs can synthesize their food through the process of photosynthesis wherein light energy is trapped and converted into chemical energy. Green plants, different tissues, and cells that are non-green require food for oxidation. Therefore, food can be translocated to all the non-green parts. Since animals are heterotrophic, they derive their nutritional requirements from plants.
The chapter deals with cellular respiration. It is the mechanism of the disintegration of food materials inside the cell to release energy. This energy is trapped to synthesize ATP, which are the energy currencies of a cell.