Chlorophyll, which is a green pigment, is the main molecule that traps energy in plants. Chlorophyll is found in the chloroplasts of plant cells. Through the photosynthesis process, chloroplasts absorb the sun's energy through the chlorophyll molecules in order to make food.
Other structures associated with the chloroplasts are the inner and outer membranes, stroma and thylakoids. Inside the chloroplast is a liquid called the stroma in which the thylakoid float. The thylakoids are the compartments that contain the chlorophyll.
Photosynthesis involves the capture of light energy by the chlorophyll which in turn keeps it in the molecule adenosine triphosphate, or ATP. This molecule combined with the reactants carbon dioxide and water produce sugar and oxygen.