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As the name implies, photosynthesis is a light-dependent reaction that occurs in autotrophic organisms. Light energy is converted to chemical energy in this process, and the carbohydrate formed is stored as food. Photosynthesis is carried out by plants, blue-green algae, and some bacteria such as purple and green-sulphur bacteria. The photosynthesis process in bacteria and plants differs. Bacterial photosynthesis is primarily an anoxygenic process in which O2 is not evolved, whereas plant photosynthesis is an oxygenic process in which O2 is evolved.
Photosynthesis Definition
Photosynthesis converts light energy to chemical energy, which is then stored in the form of glucose (sugar). Glucose, oxygen, and water are produced using inorganic compounds (carbon dioxide, water, and sunlight). Carbon is used by photosynthetic organisms to generate organic molecules (carbohydrates, lipids, and proteins) and to build biological mass. Many organisms, including plants and animals, use the oxygen produced as a byproduct of photosynthesis for cellular respiration.
Most organisms rely on photosynthesis for nutrition, either directly or indirectly. Animals, most bacteria, and fungi are heterotrophic (hetero-, -trophic) organisms that cannot photosynthesise or produce biological compounds from inorganic sources. As a result, in order to obtain these substances, they must consume photosynthetic organisms and other autotrophs (auto-, -trophs).
Difference between Bacterial Photosynthesis and Plant Photosynthesis
S.NO | Bacterial Photosynthesis | Plant Photosynthesis |
1 | Bacteriochlorophyll is the photosynthetic pigment involved. | Chlorophyll a and b are photosynthetic pigments involved in the process. |
2 | There is no production of oxygen. | Oxygen is created. |
3 | Photosynthetic bacteria do not have membrane-bound chloroplasts; rather, the photosynthetic pigment is found in the plasma membrane folds. | Chlorophyll is found in the grana of a chloroplast, which is surrounded by a double membrane. |
4 | Bacteriochlorophyll absorbs light at a higher wavelength of 800nm. | Chlorophyll absorbs light at wavelengths ranging from 400 to 750 nm. |
5 | Bacteriochlorophyll, bacterioviridin, and aliphatic carotenoids are present in addition to bacteriochlorophyll. | There are phycobilins and carotenoids present in addition to chlorophyll. |
6 | Photosynthetic bacteria have a reaction centre at P870 or P960 and use only one type of photosystem. | PS I has a reaction centre at P700, while PS II has a reaction centre at P680. |
7 | H2S or other organic compounds are used as a reducing agent. | H2O is the reducing agent. |
8 | Non-cyclic phosphorylation is common. | Cyclic phosphorylation is preferred. |
9 | Bacterial photosynthesis occurs in purple bacteria, green sulphur bacteria, phototrophic helicobacter and acidobacteria. | This occurs in plants and algae. |
Plant Photosynthesis
Photoautotrophic organisms include cyanobacteria and blue-green algae. They engage in oxygenic photosynthesis. They lack photosynthetic pigments in chloroplasts but have them in the cytoplasm. They, like plants, have chlorophyll a. A chloroplast is thought to have evolved from the cell’s endosymbiont cyanobacteria.
Photosynthetic bacteria are used in bio-fertilizers, wastewater treatment, bioremediation, and other applications. To summarise, bacterial and plant photosynthetic systems differ in structure and constituents, but both are light-dependent reactions that occur in the presence of atmospheric CO2.
The main distinction between bacterial and plant photosynthesis is the electron donor. Because H2S or thiosulfate mostly acts as an electron donor in the bacterial system and H2O mostly acts as an electron donor in the plant system, oxygen is produced in plant photosynthesis but not in bacterial photosynthesis.
Types of Photosynthesis process
The Oxygenic photosynthesis and the anoxygenic photosynthesis that are the two types of photosynthetic processes. They both work on the same principles, but oxygenic photosynthesis is the most common and is found in plants, algae, and cyanobacteria. Light energy transfers electrons from water (H2O) taken up by plant roots to CO2 to produce carbohydrates during oxygenic photosynthesis. The CO2 is “reduced,” or receives electrons, while the water is “oxidised,” or loses electrons, during this transfer.
Carbohydrates and oxygen are both produced. By absorbing CO2 produced by all breathing organisms and reintroducing oxygen into the atmosphere, oxygenic photosynthesis acts as a counterbalance to respiration. Anoxygenic photosynthesis, on the other hand, uses electron donors that are not water and do not produce oxygen, according to LibreTexts’ “Anoxygenic Photosynthetic Bacteria.” The process is most commonly seen in bacteria like green sulphur bacteria and phototrophic purple bacteria.
Conclusion
Bacterial photosynthesis occurs in purple bacteria, green sulphur bacteria, phototrophic helicobacter, and acidobacteria. Light energy is converted to chemical energy in this process, and the carbohydrate formed is stored as food. Photosynthesis is carried out by plants, blue-green algae, and some bacteria such as purple and green-sulphur bacteria. The photosynthesis process in bacteria and plants differs. Bacterial photosynthesis is primarily an anoxygenic process in which O2 is not evolved, whereas plant photosynthesis is an oxygenic process in which O2 is evolved. Chlorophyll a and b are photosynthetic pigments involved in the process. The main distinction between bacterial and plant photosynthesis is the electron donor. They both work on the same principles, but oxygenic photosynthesis is the most common and is found in plants, algae, and cyanobacteria.
