What molecule is primarily responsible for capturing sunlight in plants?

Chlorophyll is the molecule primarily responsible for capturing sunlight in plants. This green pigment is found in the chloroplasts of plant cells and plays a critical role in photosynthesis, the process by which plants convert light energy into chemical energy. When chlorophyll absorbs sunlight, it facilitates the conversion of carbon dioxide and water into glucose, which the plant uses for energy and growth, while also releasing oxygen as a byproduct.

Other molecules mentioned serve different functions in plants. Glucose is a product of photosynthesis and serves as an energy source, but it is not involved in capturing light. Cellulose is a structural component of plant cell walls, providing rigidity and strength, and is not involved in light absorption either. Starch is a storage carbohydrate that plants use to store energy, but like glucose, it does not participate in the process of capturing sunlight. Thus, chlorophyll stands out as the essential molecule for harnessing solar energy.