Photosynthesis

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  • Topic: Photosynthesis, C4 carbon fixation, Calvin cycle
  • Pages : 4 (1291 words )
  • Download(s) : 77
  • Published : May 20, 2013
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Photosynthesis

Light reaction of photosynthesis occurs on the thylakoid membrane inside of chloroplast. Light energy excites electrons that are carried down an electron transport chain. The purpose of this is to give the hydrogen ions the energy they need for active transport. It is active because the concentration of hydrogen ions outside the thylakoid is less than inside. Now that there is a high concentration of hydrogen inside the thylakoid, ATP synthase can occur. As the hydrogen go through the ATP synthase ATP (energy) is produced. The main difference between the C3 and C4 cycle is that carbon dioxide directly enters the Calvin cycle in C3 plants. C3 plants do better in high CO2 environments.

Photosynthesis consists of light reactions and dark reactions. Light dependent reactions are reactions taking place in the chloroplast in which the absorption of a photo leads to the formation of ATP and NADPH. Light independent reactions are the series of biochemical reactions in photosynthesis that do not require light to proceed, and ultimately produce organic molecules from carbon dioxide. This process can be simplified in this equation: 6CO2 + 12H2O+energy= C6H12O6. It means photosynthesis is a process in which carbon dioxide (CO2), water (H2O) and light energy are utilized to synthesize an energy-rich carbohydrate like glucose (C6H12O6) and to produce oxygen (O2) as a by-product. Photoautotrophs are organisms that use light energy to drive the synthesis of organic molecules from a carbon dioxide and in most cases, water. Photosynthesis is a vital process among photoautotrophs, like plants, algae and some bacteria that are able to create their own food directly from inorganic compounds using light energy so that they do not have to eat or rely on nutrients derived from other living organisms. Photosynthesis occurs in plastids, which are membrane-bounded organelles containing photosynthetic pigments (e.g. chlorophyll), within the cells of plants and algae....
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