This conserves water during the day, but prevents CO 2 from entering the leaves. When stomata are open at night, CO 2 is taken up and incorporated into a variety of organic acids. The organic acids made at night are stored in vacuoles of mesophyll cells until morning, when the stomata close. At this time, CO 2 is released from the organic acids made the previous night and is incorporated into sugar in the chloroplasts. No other chemical process on Earth is more productive or is as important to life.
Photosynthesis transforms light energy to chemical bond energy in sugar molecules.
Sugars made in chloroplasts supply the entire plant with chemical energy and carbon skeletons to synthesize organic molecules. Nonphotosynthetic parts of a plant depend on organic molecules exported from leaves in veins. The disaccharide sucrose is the transport form of carbohydrate in most plants. Sucrose is the raw material for cellular respiration and many anabolic pathways in nonphotosynthetic cells. Much of the sugar is glucose - the monomer linked to form cellulose , the main constituent of plant cell walls.