The stream carries them until they lodge against a muddy bank where they can germinate. Animal carriers Animals can disperse plant seeds and fruits in two ways. The hooked spines of the burrs of certain plants can become caught in the animal's fur and dispersed as the animal grazers or, more commonly, the seed may be enclosed inside a tempting juicy fruit. Such fruits often change colour dramatically from green to red or purple when they are ripe, indicating to animals that they are now sweet and ready to eat. Making sunlight into food In green plants and algae, photosynthesis takes place in the chloroplasts, miniature solar converters inside the plant's cells.
Chloroplasts contain the green pigment chlorophyll, which absorbs light .
Carbon dioxide from the air provides the carbon atoms for these organic compounds. Sugars are used by the plant as fuel for respiration, which generates chemical energy to power biochemical reactions essential for survival and growth. Respiration also produces carbon dioxide as a waste product, which can then be used again for photosynthesis. The products of photosynthesis also represent the starting point for the formation of other simple organic molecules. These can then be combined into larger molecules such as proteins, nucleic acids, polysaccharides and lipids, from which all living material is made.