Question

How are cellular respiration and photosynthesis dependent on each other?

Answer 1

The end product of the photosynthesis reaction is glucose or sugar molecules. The glucose molecule is further converted into ATP by the process of respiration.

Complete answer:
Photosynthesis is a chemical process used by green plants and few other organisms to convert light energy into chemical energy. The chemical energy is stored in the form of sugars in the organisms. The sugar produced by this process is converted into ATP. Sunlight functions as the main source of light energy, while carbon dioxide and water are the main reactants.

The set of chemical metabolic reactions that occur in living organisms to produce energy through the breakdown of food molecules or sugar molecules by the action of oxygen is called cellular respiration. The reactants of this reaction are- oxygen and glucose. ATP (Adenosine Triphosphate) and waste products like- carbon dioxide and water are the products obtained. The ATP produced in cellular respiration is used by- organisms to perform several functions like - regulation of heart rate, movement of muscles and bones, thinking, growth and development, maintenance of the metabolic reactions that keep the cells and our body healthy, digestion, various physical cavities, etc.

Photosynthesis and cellular respiration are dependent on each other as the products of each of these reactions initiate the other reaction. The sugar molecules or glucose molecules produced in the reaction of photosynthesis are used as reactant molecules in the respiration reaction. The glucose molecules are broken down to form energy molecules of ATP. Carbon dioxide is released into the atmosphere as a by-product. The carbon dioxide is further used as a reactant molecule in the reaction of photosynthesis. The products of one reaction are used as reactants in other reactions and thus, both the processes are responsible for the survival of life.

Note: Photosynthesis is not a reversible reaction as the formation of glucose is a chemical change, which cannot be reversed. Therefore, the light energy can be converted into chemical energy but the opposite cannot occur. Similarly, respiration is also an irreversible process.