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[citation needed] He called them cancroïde, later changing the name to chéloïde to avoid confusion with cancer. The word is derived from the Ancient Greek χηλή, chele, meaning "crab pincers", and the suffix -oid, meaning "like". In the 19th century it was known as the "Keloid of Alibert" as opposed to "Addison’s keloid" . [24]
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 .
The light-harvesting system of PSI uses multiple copies of the same transmembrane proteins used by PSII. The energy of absorbed light (in the form of delocalized, high-energy electrons) is funneled into the reaction center, where it excites special chlorophyll molecules (P700, with maximum light absorption at 700 nm) to a higher energy level.
They are non-thermal in origin, and the emission of biophotons is technically a type of bioluminescence, though the term "bioluminescence" is generally reserved for higher luminance systems (typically with emitted light visible to the naked eye, using biochemical means such as luciferin/luciferase).
In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; [2] in others, it is autogenic, produced by the animals themselves. In most cases, the principal chemical reaction in bioluminescence involves the reaction of a substrate called luciferin and an enzyme , called luciferase .
The light and heat produced by the bubble may have no direct significance, as it is the shockwave produced by the rapidly collapsing bubble which these shrimp use to stun or kill prey. However, it is the first known instance of an animal producing light by this effect and was whimsically dubbed "shrimpoluminescence" upon its discovery in 2001. [27]
The wavelengths produced by most photocytes fall close to 490 nm, although light as energetic as 250 nm is reportedly possible. [ 1 ] The variations of color seen in different photocytes are usually the result of color filters in other parts of the photophore that alter the wavelength of the light prior to exiting the endoderm .
These light-emitting organisms are found mainly in coastal waters near the outflow of rivers, such as the northern Adriatic Sea, Gulf of Trieste, northwestern part of the Caspian Sea, coast of Africa and many more. [25] These are known as milky seas. Bioluminescent bacteria are also found in freshwater and terrestrial environments but are less ...