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Photosynthesis


Photosynthesis
Photosynthesis (from the Greek φώτο-[photo-], "light," and σύνθεσις [synthesis], "merge", "merger") is a biochemical process in the formation of carbohydrate food substances made by plants, especially plants that contain chlorophyll leaves or chlorophyll. In addition to chlorophyll plants, living beings other non-photosynthetic chlorophyll is algae and some bacteria. These organisms photosynthesize using the nutrients, carbon dioxide, and water and sunlight energy assistance.

Fotoautotrof photosynthetic organisms called because they can make their own food. In plants, algae, and cyanobacteria, photosynthesis performed by utilizing carbon dioxide and water and produces a waste product of oxygen. Photosynthesis is vital for all aerobic life on Earth because in addition to maintaining a normal level of oxygen in the atmosphere, photosynthesis is also the source of energy for almost all life on Earth, either directly (through primary production) or indirectly (as the main source of energy in their food ), except kemoautotrof organisms that live on the rocks or in hydrothermal vents in the deep ocean. Rate of absorption of energy by photosynthesis is very high, which is about 100 terawatt, or roughly six times larger than the energy consumption of human civilization. In addition to energy, photosynthesis is also the source of carbon for all the organic compounds in the body of an organism. Photosynthesis change around 100-115 petagram carbon into biomass per year.

Although photosynthesis can take place in different ways in different species, some characteristics are always the same. For example, the process always begins with the light energy absorbed by chlorophyll proteins called photosynthetic reaction centers. In plants, these proteins are stored in organelles called chloroplasts, while in bacteria, these proteins are stored in the plasma membrane. Some of the light energy gathered by chlorophylls is stored in the form of adenosine triphosphate (ATP). The rest of the energy is used to separate electrons from a substance such as water. These electrons are used in the reaction that converts karbondioksia into organic compounds. In plants, algae, and cyanobacteria, this is done in a series of reactions called the Calvin cycle, but different series of reactions are found in some bacteria, such as reverse Krebs cycle in Chlorobium. Many photosynthetic organisms have adaptations that concentrate or store carbon dioxide. It helps reduce wasteful process called photorespiration that can spend most of the sugar produced during photosynthesis.

The first photosynthetic organisms likely evolved about 3,500 million years ago, early in the evolutionary history of life when all forms of life on Earth are microorganisms and the atmosphere had a large amount of carbon dioxide. Living things when it's quite likely utilize hydrogen or hydrogen sulfide - not water - as a source of electrons. Cyanobacteria appeared later, around 3,000 million years ago, and drastically changed the Earth when they began mengoksigenkan atmosphere at about 2,400 million years ago. This new atmosphere allowed the evolution of complex life are like protists. In the end, no less than a billion years ago, one of protists formed a symbiotic relationship with cyanobacteria and generate ancestor of all plants and algae. Chloroplasts in modern plants are the descendants of this symbiotic cyanobacteria.

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