The light phase of photosynthesis: the nature of the process

Photosynthesis as a chemical phenomenon is a process in which the formation of organic compounds occurs during the interaction of water and carbon dioxide. An indispensable condition is the course of the process in the light, with the direct participation of photosynthetic substances. For the vegetable world, such substances are chlorophyll, for bacteria - bacteriochlorophyll.

This reaction is multi-stage in nature and is of a quantum nature. Multistage is manifested in the fact that in the course of photosynthesis processes of reception, transformation and utilization of the accepted quantum energy of light are successively proceeding. One of these transformations is the process of transformation of carbon dioxide into organic matter. And the process, during which there are energy-saturated molecules and ATP compounds, called the light phase of photosynthesis. The main condition and factor of this phase is the presence of light energy. The mechanism of providing such a transformation as the light phase of photosynthesis can be schematically represented as follows. Chlorophyll, which is found on membranes in plant chloroplasts, absorbs light fluxes of solar energy. Then this energy promotes the combination of elements of phosphoric acid with elements of ATP and ADP molecules. However, the work of light energy does not end there either. In addition to influencing the process of fusion of molecules, this energy makes it possible to carry out the splitting reaction of water elements. Here the light phase of photosynthesis proceeds in the form of the reaction 2H20 = 4H + + 4e- + O2. As we can see, the result of this reaction is released oxygen, which then in a free form simply enters the natural environment.

The next stage, during which the light phase of photosynthesis is realized, is the activation of chlorophyll molecules. During this process, under the influence of light quanta, the electron of the chlorophyll molecule moves to a higher electronic level in the molecule structure. Catalysts and carriers of this electron are elements of chloroplast proteins. Passing through some sequence of these carrier proteins, the electron of the molecule of chlorophyll is forced to lose its energy, and it is spent to maintain the oxidation-reduction process in ATP molecules.

Having lost their energy and elements (electrons) in this way, the chlorophyll molecules are restored due to the addition of electrons, which appeared as a result of the above-mentioned reaction of the splitting of the water molecule. The resulting hydrogen during this cleavage is synthesized with another substance, which will be able to perform the role of its transporter within the chloroplast.

Plants, naturally, exist also in conditions of darkness, that is when the flow of light energy is absent. Therefore, the dark stage of photosynthesis takes place, which takes place in the space enclosed between the shell and the thylakoids of the chloroplast. For this phase, no light energy is needed, and the reaction itself consists of the processes of successive transformation of carbon dioxide molecules entering their atmospheric air. The result of such transformations is the formation of glucose molecules, primarily, and other organic compounds. Such compounds are amino acids, nucleotides, as well as all known glycerol.

In addition to the division into the phases of photosynthesis, in science the classification of this natural process according to types is considered. The main ones are C3-photosynthesis, and C4-photosynthesis, at which three- and four-carbon compounds are formed, respectively.