But they become normally green only after light exposure. Within them the reactions of photosynthesis take place. They enable the plants to convert solar energy into chemical energy. This process is the cause why plant are also called primary producers . The existence of consumers, like most animals, depends on them.
Chloroplasts occur in most cell types but only in organs above ground.
Here are they rather large and of a lens-shaped appearance. Under the influence of the diffuse daylight are they mainly found at the upper and lower surface of the chloroplast. They do therefore seem to be round when viewed from above. They regroup parallel to the lateral sides of the cell under exposure to strong light and are then viewed as elliptic. Starch production during photosynthesis can be made visible by placing a mask at a leave that covers it partially and leaves some places exposed to sunlight.