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The average rate of energy captured by global photosynthesis is approximately 130 terawatts, [6] [7] [8] which is about eight times the total power consumption of human civilization. [9] Photosynthetic organisms also convert around 100–115 billion tons (91–104 Pg petagrams , or billions of metric tons), of carbon into biomass per year.
The following is a breakdown of the energetics of the photosynthesis process from Photosynthesis by Hall and Rao: [6]. Starting with the solar spectrum falling on a leaf, 47% lost due to photons outside the 400–700 nm active range (chlorophyll uses photons between 400 and 700 nm, extracting the energy of one 700 nm photon from each one)
This is one of two core processes in photosynthesis, and it occurs with astonishing efficiency (greater than 90%) because, in addition to direct excitation by light at 680 nm, the energy of light first harvested by antenna proteins at other wavelengths in the light-harvesting system is also transferred to these special chlorophyll molecules.
The scientist Charles Barnes first used the word 'photosynthesis' in 1893. 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'.
A simplified overall formula for photosynthesis is [79] 6 CO 2 + 6 H 2 O + photons → C 6 H 12 O 6 + 6 O 2. or simply carbon dioxide + water + sunlight → glucose + dioxygen. Photolytic oxygen evolution occurs in the thylakoid membranes of photosynthetic organisms and requires the energy of four photons.
Diagram of the chemical equation of the electrolysis of water, ... (PEC) process. The system is also named artificial photosynthesis. [7] [8] [9] [10]
Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12 C and 1.1% in 13 C. [1] [8] The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. [1]
Glucose is a sugar with the molecular formula C 6 H 12 O 6.It is overall the most abundant monosaccharide, [4] a subcategory of carbohydrates.It is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight.