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Heliotropism, a form of tropism, is the diurnal or seasonal motion of plant parts (flowers or leaves) in response to the direction of the Sun. The habit of some plants to move in the direction of the Sun, a form of tropism, was already known by the Ancient Greeks. They named one of those plants after that property Heliotropium, meaning "sun turn".
The fact that a reaction is thermodynamically possible does not mean that it will actually occur. A mixture of hydrogen gas and oxygen gas does not spontaneously ignite. It is necessary either to supply an activation energy or to lower the intrinsic activation energy of the system, in order to make most biochemical reactions proceed at a useful ...
Plant pigments usually utilize the last two of these reactions to convert the sun's energy into their own. This initial charge separation occurs in less than 10 picoseconds (10 -11 seconds). In their high-energy states, the special pigment and the acceptor could undergo charge recombination; that is, the electron on the acceptor could move back ...
[28] [42] Lockwood and Fröhlich, 2007, found "considerable evidence for solar influence on the Earth's pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century", but that "over the past 20 years, all the trends in the Sun that could have had an influence on the Earth ...
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)
Such archaeal photosynthesis might have been the earliest form of photosynthesis that evolved on Earth, as far back as the Paleoarchean, preceding that of cyanobacteria (see Purple Earth hypothesis). While the details may differ between species , the process always begins when light energy is absorbed by the reaction centers , proteins that ...
For example, in the carbon cycle, atmospheric carbon dioxide is absorbed by plants through photosynthesis, which converts it into organic compounds that are used by organisms for energy and growth. Carbon is then released back into the atmosphere through respiration and decomposition.
Water is the medium of the oceans, the medium which carries all the substances and elements involved in the marine biogeochemical cycles. Water as found in nature almost always includes dissolved substances, so water has been described as the "universal solvent" for its ability to dissolve so many substances.