Life

Photosynthesis

All living beings are largely composed of organic molecules (sugars, fats, proteins, etc.), that are produced from other molecules (synthesis). Plants are however different from animals, since they use different molecules in the process. Actually, green plants produce the organic substances their body is made of by using a limited number of inorganic substances that can be found in the environment, such as carbon dioxide (contained in air) and water and some inorganic ions (nitrates, sulphates, and other substances contained in soil). In particular, green plants can use solar energy to trap and turn into organic molecules the carbon contained in the atmosphere in the form of carbon dioxide. This process is called photosynthesis and is typical of autotrophic organisms. All the other organisms that cannot accomplish the photosynthesis process, such as man or animals, are called heterotrophic organisms. Heterotrophic organisms can synthesise the molecules their body is made of only by using the organic molecules contained in food (vegetal or animal food). Vegetal species are therefore an essential element for natural balance and for the life of other living species.