Photosynthesis is the process by which plants and some microorganisms make substances like carbohydrates. It is an endothermic (takes in heat) chemical process that uses sunlight to turn carbon dioxide into sugars. The sugars are used by the cell as energy, and to build other kinds of molecules.The definition of photosynthesis is the process through which plants use water and carbon dioxide to create their food, grow and release excess oxygen into the air. Photosynthesis uses sunlight, carbon dioxide and water to produce oxygen, glucose and water.Photosynthesis is a physio-chemical process which uses light energy to produce organic compounds. Photosynthesis is essential as it not only is the primary source of food for living entities but it also releases oxygen into the atmosphere which is required to breathe.Photosynthesis is important to living organisms because it is the number one source of oxygen in the atmosphere. Without photosynthesis, the carbon cycle could not occur, oxygen-requiring life would not survive and plants would die. ... The importance of photosynthesis in our life is the oxygen it produces