Figure 2.

The abstract’s page. Hyperlinks to further text (yellow button) and non-textual information sources (thumbnails on the left side) are available. The top-left button is present in all pages and permits users to go back to the previously explored pages. It can also be seen that the main page is blurred underneath. The time remaining is displayed on the top. The text in English is: The word photosynthesis comes from the Greek “photo”—light—and “synthesis”—composition—and takes place in plants, algae, and some bacteria, though not in archeobacteria. The organisms that have photosynthesis are also called “photoautotrophs”. However, not all organisms that use light as a source of energy have photosynthesis, because the “photoheterotrophs” use organic compounds, instead of carbon dioxide, as the carbon source. Among plants, algae, and cyanobacteria photosynthesis uses carbon dioxide and water, and it releases oxygen as a residual. Hence, photosynthesis is central for life in the Earth, both to preserve the atmospheric normal level of oxygen, and many forms of life that depend on photosynthesis to gather energy are what many other species feed on. The amount of energy captured by photosynthesis is huge—some 100 Terawatts—approximately six times the energy consumed yearly by human civilisation. Furthermore, photosynthetic organisms fix 100,000 million tons of carbon into biomass each year. Despite it can take place in different forms, depending on the species, some of its traits are steady and regular.