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Light-dependent reactions of photosynthesis at the thylakoid membrane. 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).
This word is taken from two Greek words, photos, which means light, and synthesis, which in chemistry means making a substance by combining simpler substances. So, in the presence of light, synthesis of food is called 'photosynthesis'. Noncyclic photophosphorylation through light-dependent reactions of photosynthesis at the thylakoid membrane.
Photosynthesis occurs in two stages. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the hydrogen carrier NADPH and the energy-storage molecule ATP. During the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide.
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 6 H 2 O + 6 CO 2 + energy → C 6 H 12 O 6 + 6 O 2
By studying purple sulphur bacteria and green sulphur bacteria he was the first scientist to demonstrate, in 1931, that photosynthesis is a light-dependent redox reaction [2] in which hydrogen from an oxidizable compound reduces carbon dioxide to cellular materials. Expressed as: 2 H 2 A + CO 2 → 2A + CH 2 O + H 2 O
The overall general equation for the light-independent reactions is the following: [11] 3 CO 2 + 9 ATP + 6 NADPH + 6 H + → C 3 H 6 O 3 -phosphate + 9 ADP + 8 P i + 6 NADP + + 3 H 2 O The 3-carbon products (C 3 H 6 O 3 -phosphate) of the Calvin cycle are later converted to glucose or other carbohydrates such as starch , sucrose , and cellulose .
The antenna complex is where light is captured, while the reaction center is where this light energy is transformed into chemical energy. At the reaction center, there are many polypeptides that are surrounded by pigment proteins. At the center of the reaction center is a special pair of chlorophyll molecules. Each PSII has about 8 LHCII.
The Calvin cycle, light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle [1] of photosynthesis is a series of chemical reactions that convert carbon dioxide and hydrogen-carrier compounds into glucose. The Calvin cycle is present in all photosynthetic eukaryotes and also many ...