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PHOTOSYNTHESIS (Photosynthesis includes many reactions, divided into two…
PHOTOSYNTHESIS
Photosynthesis includes many reactions, divided into two main steps
Stage light 
The reactions of the light phase transform solar energy into chemical energy. In this phase, the light is used to convert ADP into ATP molecules and to reduce the coenzyme NADP *
In photosynthetic organisms, pigments capable of absorbing the energy of light used for photosynthesis are the chlorophylls, carotenoids, and phycobilins.
The chlorophyll performs two essential functions: 1) absorbs the light energy and transforms it into chemical energy, in the form of excited electrons;
2) yields such electrons to other molecules
In plants, the pigments are organized into complex structures called photosystems.
The photosystems are localized in the thylakoid membrane and are formed by many molecules of chlorophyll and accessory pigments
each photosystem comprises an antenna system capable of absorbing the light energy and a reaction center where the redox reactions occur that operate the conversion of light energy into chemical energy
once the light energy has been converted into chemical energy of the excited chlorophyll molecule reduces a primary acceptor molecule called through a redox reaction
The primary acceptor is the first of a series of electron carriers who take part in a process called electron flow.
The product of the reaction, ie the NADPH, is a reduced coenzyme energy-rich
Dark phase
The independent reactions by the light, which constitute the Calvin cycle, using ATP and NADPH to synthesize sugars from CO2.
Today we know that the calvin cycle consists of three processes;
1) carbon fixation, this reaction. It is catalyzed by Rubisco (the most abundant protein on Earth)
2) the reduction of 3PG to G3P
3) regeneration RuBP.
the product of the Calvin cycle is the G3P, however, an amount of this can be transformed into pyruvate, starch or sucrose
In the eucariotis the two phases happen in the cloroplastis: the bright reactions take place in the membrane of the tilacoids, while those independent from the light happen in the stromae.
Unoxygenic
Some types of bacteria that live in environments devoid of oxygen perform such photosynthesis using solar energy to convert CO2 into more complex molecules, without producing O2. different from the water molecules assume the function of electron donors.
Oxygenic
The plants, algae and cyanobacteria that live in aerobic environments perform this type of photosynthesis, ie the conversion of carbon dioxide and water into sugar and oxygen.
The photosynthesis is the anabolic process that allows you to capture light energy and use it to synthesise carbohydrates
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