What is photosynthesis?

Photosynthesis is the process by which green plants, algae, and some bacteria convert sunlight into chemical energy to fuel their growth and metabolism. Essentially, plants take in sunlight and use it to transform carbon dioxide from the air and water from the soil into glucose, a type of sugar that serves as food. Oxygen is released as a byproduct during this process. The process occurs mainly in the leaves, specifically within specialized structures called chloroplasts that contain a green pigment called chlorophyll. Chlorophyll absorbs light energy, primarily from the blue and red parts of the spectrum. This energy excites electrons, initiating a series of chemical reactions known as the light-dependent and light-independent (Calvin cycle) reactions. In the light-dependent reactions, the absorbed sunlight energy is used to split water molecules into oxygen, protons, and electrons, producing energy-rich molecules like ATP and NADPH. Then, in the light-independent reactions, these molecules help convert carbon dioxide into glucose through a cycle of enzymatic steps. This glucose can then be used by the plant for energy or to build other important compounds. In summary, photosynthesis is how plants convert sunlight, water, and carbon dioxide into glucose and oxygen, sustaining not only themselves but also providing oxygen and food for other living organisms.