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The Function of Carotenoid Pigments in Photosynthesis …

Carotenoids are essential for the survival of photosynthetic organisms.

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the role of carotenoids in natural and artificial photosynthesis ..

The human intake of carotenoids may be appreciated using databases such as that establlished for Swiss vegetables ().
Carotenoids are important components of the light harvesting in plants, expanding the absorption spectra of photosynthesis.

Carotenoids are usually considered to perform two major functions in photosynthesis.

The carotenoids are distributed widely in nature and have wide range functions,for example, light harvesting and photoprotective roles in photosynthesis and ROS scavenging.

PHOTOSYNTHESIS A 12 Å carotenoid translocation in a …

Carotenoid pigments are found in many photosynthetic organisms, as well as in plants

Drawing upon recent work with photosynthetic bacteria, evidence is presented as to how the carotenoids are organized within both portions of the photosynthetic unit (the light harvesting antenna and the reaction centre) and how they discharge both their functions.

Among them, isorenieratane, found in oils of Devonian age, is derived from the carotenoid isorenieratene (an homologue of the previous one but with an unsaturated isoprenoid chain), which is synthesized by photosynthetic green sulfur bacteria (Chlorobiaceae)().

autumnalchanges | Carotenoid | Photosynthesis

08/01/2018 · What is function of carotene in photosynthesis

A series of phthalocyanine−carotenoid dyads in which a phenylamino group links a phthalocyanine to carotenoids having 8−11 backbone double bonds were examined by visible and near-infrared femtosecond pump−probe spectroscopy combined with global fitting analysis. The series of molecules has permitted investigation of the role of carotenoids in the quenching of excited states of cyclic tetrapyrroles. The transient behavior varied dramatically with the length of the carotenoid and the solvent environment. Clear spectroscopic signatures of radical species revealed photoinduced electron transfer as the main quenching mechanism for all dyads dissolved in a polar solvent (THF), and the quenching rate was almost independent of carotenoid length. However, in a nonpolar solvent (toluene), quenching rates displayed a strong dependence on the conjugation length of the carotenoid and the mechanism did not include charge separation. The lack of any rise time components of a carotenoid S1 signature in all experiments in toluene suggests that an excitonic coupling between the carotenoid S1 state and phthalocyanine Q state, rather than a conventional energy transfer process, is the major mechanism of quenching. A pronounced inhomogeneity of the system was observed and attributed to the presence of a phenyl-amino linker between phthalocyanine and carotenoids. On the basis of accumulated work on various caroteno−phthalocyanine dyads and triads, we have now identified three mechanisms of tetrapyrrole singlet excited state quenching by carotenoids in artificial systems: (i) Car−Pc electron transfer and recombination; (ii)1 Pc to Car S1 energy transfer and fast internal conversion to the Car ground state; (iii) excitonic coupling between 1Pc and Car S1 and ensuing internal conversion to the ground state of the carotenoid. The dominant mechanism depends upon the exact molecular architecture and solvent environment. These synthetic systems are providing a deeper understanding of structural and environmental effects on the interactions between carotenoids and tetrapyrroles and thereby better defining their role in controlling natural photosynthetic systems.

AB - Green plants use the xanthophyll cycle to regulate the flow of energy to chlorophyll a within photosynthetic proteins. Under conditions of low light intensity violaxanthin, a carotenoid possessing nine conjugated double bonds, functions as an antenna pigment by transferring energy from its lowest excited singlet state to that of chlorophyll a within light-harvesting proteins. When the light intensity increases, violaxanthin is biochemically transformed into zeaxanthin, a carotenoid that possesses eleven conjugated double bonds. The results presented here show that extension of the {squared rising diagonal slash} conjugation of the polyene lowers the energy of the lowest excited singlet state of the carotenoid below that of chlorophyll a. As a consequence zeaxanthin can act as a trap for the excess excitation energy on chlorophyll a pigments within the protein, thus regulating the flow of energy within photosynthetic light-harvesting proteins.

On Jan 1, 2003, Bacon Ke published the chapter: Role of Carotenoids in Photosynthesis in the book: Photosynthesis.
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  • What Are Carotenoids? - Live Science

    Carotenoid - Wikipedia

  • Consume More Carotenoids for Improved Skin & Eye …

    Carotenoids are a widely distributed group of naturally occurring pigments, usually red, orange or yellow in color

  • Pigments for Photosynthesis - HyperPhysics Concepts

    β-Cryptoxanthin

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Like α- and β-carotene, β-cryptoxanthin is a provitamin A carotenoid

Green plants use the xanthophyll cycle to regulate the flow of energy to chlorophyll a within photosynthetic proteins. Under conditions of low light intensity violaxanthin, a carotenoid possessing nine conjugated double bonds, functions as an antenna pigment by transferring energy from its lowest excited singlet state to that of chlorophyll a within light-harvesting proteins. When the light intensity increases, violaxanthin is biochemically transformed into zeaxanthin, a carotenoid that possesses eleven conjugated double bonds. The results presented here show that extension of the {squared rising diagonal slash} conjugation of the polyene lowers the energy of the lowest excited singlet state of the carotenoid below that of chlorophyll a. As a consequence zeaxanthin can act as a trap for the excess excitation energy on chlorophyll a pigments within the protein, thus regulating the flow of energy within photosynthetic light-harvesting proteins.

Lutein definition, Also called xanthophyll

Measurement of the of these pigments as a function of photosynthetic output makes it clear that the are the most important, but that beta carotene contributes.

The Photosynthetic Habits of Highly Effective Plants

N2 - Green plants use the xanthophyll cycle to regulate the flow of energy to chlorophyll a within photosynthetic proteins. Under conditions of low light intensity violaxanthin, a carotenoid possessing nine conjugated double bonds, functions as an antenna pigment by transferring energy from its lowest excited singlet state to that of chlorophyll a within light-harvesting proteins. When the light intensity increases, violaxanthin is biochemically transformed into zeaxanthin, a carotenoid that possesses eleven conjugated double bonds. The results presented here show that extension of the {squared rising diagonal slash} conjugation of the polyene lowers the energy of the lowest excited singlet state of the carotenoid below that of chlorophyll a. As a consequence zeaxanthin can act as a trap for the excess excitation energy on chlorophyll a pigments within the protein, thus regulating the flow of energy within photosynthetic light-harvesting proteins.

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