What green substance found in chloroplasts is essential for photosynthesis?

Chlorophyll is the green pigment found in chloroplasts that plays a crucial role in the process of photosynthesis. This pigment absorbs light energy, primarily from the sun, and uses it to convert carbon dioxide and water into glucose and oxygen. Chlorophyll's ability to capture light energy is what allows plants to harness the energy needed for photosynthesis, making it essential for the growth and development of the plant.

While glucose is a product of photosynthesis, it is not involved in capturing light energy. Cellulose is a structural component of plant cell walls, which provides rigidity, but it does not play a role in the photosynthetic process. Oxygen is also a byproduct of photosynthesis, released into the atmosphere, but it is not the substance responsible for capturing light energy. Hence, chlorophyll is the key player in enabling plants to produce their food and contribute to the Earth's oxygen supply.