Photosynthesis or chlorophyll function is a chemical process that consists of the conversion of inorganic matter to organic matter thanks to the energy provided by sunlight. In this process, light energy is transformed into stable chemical energy, with NADPH (nicotine adenine dinucleotide phosphate) and ATP (adenosine triphosphate) being the first molecules in which this chemical energy is stored. Subsequently, the reducing power of NADPH and the energy potential of the phosphate group of ATP are used for the synthesis of carbohydrates from the reduction of carbon dioxide (CO2). Life on our planet is fundamentally maintained thanks to the photosynthesis carried out in the aquatic environment by algae, cyanobacteria, red bacteria, purple bacteria, green sulfur bacteria,1 and in the terrestrial environment by plants, which have the ability to synthesize organic matter (essential for the constitution of living beings) starting from light and inorganic matter. In fact, each year photosynthesizing organisms fix around 100 billion tons of carbon in the form of organic matter The cytoplasmic organelles responsible for carrying out photosynthesis are the chloroplasts, polymorphous structures that are green in color (this coloration is due to the presence of the pigment chlorophyll) typical of plant cells. Inside these organelles is a chamber that houses an internal environment called the stroma, which houses various components, including enzymes responsible for the transformation of carbon dioxide into organic matter and flattened saccules called thylakoids, whose membrane contains photosynthetic pigments. On average, a leaf cell has between fifty and sixty chloroplasts inside it. Organisms that have the ability to carry out photosynthesis are called photoautotrophs (another possible nomenclature is that of autotrophs, but it must be taken into account that bacteria that carry out chemosynthesis are also included under this name) and fix atmospheric CO2 . At present, two types of photosynthetic processes are differentiated, which are oxygenic photosynthesis and anoxygenic photosynthesis. The first of the modalities is that of higher plants, algae and cyanobacteria, where the donor of electrons is water and, as a consequence, oxygen is released. While the second, also known by the name of bacterial photosynthesis, is carried out by purple and green sulfur bacteria, in which the electron donor is hydrogen sulfide (H2S), and consequently, the chemical element released will not be oxygen. but sulfur, which can be accumulated inside the bacteria, or failing that, expelled into the water.
