Which molecule is essential for capturing light energy during photosynthesis?

Chlorophyll is the pigment primarily responsible for capturing light energy during photosynthesis. It is located in the chloroplasts of plant cells and absorbs light most efficiently in the blue and red wavelengths, while reflecting green light, which is why plants appear green. This captured light energy is crucial for powering the conversion of carbon dioxide and water into glucose and oxygen through the photosynthetic process.

The other molecules listed play different roles: glucose is the product of photosynthesis, serving as an energy source for the plant; water is a reactant that provides electrons and protons during the light-dependent reactions; and starch is a storage form of glucose, used by plants to store energy for later use.