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Photosynthesis (/ ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [ 1 ] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism. Photosynthesis usually refers to oxygenic photosynthesis, a process that produces oxygen ...
Light-dependent reactions are certain photochemical reactions involved in photosynthesis, the main process by which plants acquire energy. There are two light dependent reactions: the first occurs at photosystem II (PSII) and the second occurs at photosystem I (PSI).
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety ...
Photosystem. Photosystems are functional and structural units of protein complexes involved in photosynthesis. Together they carry out the primary photochemistry of photosynthesis: the absorption of light and the transfer of energy and electrons. Photosystems are found in the thylakoid membranes of plants, algae, and cyanobacteria.
Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. [1] Oxygenic photosynthesis was the primary source of free oxygen and led to the Great Oxidation Event roughly 2.4 to 2.1 billion years ago during the Neoarchean - Paleoproterozoic boundary. [2 ...
Ecosystem respiration is the sum of all respiration occurring by the living organisms in a specific ecosystem. [1] The two main processes that contribute to ecosystem respiration are photosynthesis and cellular respiration. Photosynthesis uses carbon-dioxide and water, in the presence of sunlight to produce glucose and oxygen whereas cellular ...
The photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in green plants and algae. Photosynthesis can be described by the simplified chemical reaction where C 6 H 12 O 6 is glucose (which is subsequently transformed into other sugars, starches, cellulose, lignin, and so forth).
The chemical pathway of oxygenic photosynthesis fixes carbon in two stages: the light-dependent reactions and the light-independent reactions. The light-dependent reactions capture light energy to transfer electrons from water and convert NADP +, ADP, and inorganic phosphate into the energy-storage molecules NADPH and ATP.