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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)
Photosynthesis usually refers to oxygenic photosynthesis, a process that produces oxygen. Photosynthetic organisms store the chemical energy so produced within intracellular organic compounds (compounds containing carbon) like sugars, glycogen , cellulose and starches .
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'.
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 CO 2 compensation point (Γ) is the CO 2 concentration at which the rate of photosynthesis exactly matches the rate of respiration. There is a significant difference in Γ between C 3 plants and C 4 plants: on land, the typical value for Γ in a C 3 plant ranges from 40–100 μmol/mol, while in C 4 plants the values are lower at 3–10 μmol/mol. Plants with a weaker CCM, such as C2 ...
Today, C 4 plants represent about 5% of Earth's plant biomass and 3% of its known plant species. [18] [25] Despite this scarcity, they account for about 23% of terrestrial carbon fixation. [26] [27] Increasing the proportion of C 4 plants on earth could assist biosequestration of CO 2 and represent an important climate change avoidance
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 respiration uses glucose and oxygen to produce carbon-dioxide, water, and energy.
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.