Photosynthesis/Addendum: Difference between revisions
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===Evolution of Photosynthesis=== | ===Evolution of Photosynthesis=== | ||
"'''Evolution of Photosynthesis'''"<ref name=hm&b2011/> | |||
*<font face="Gill Sans MT">Energy conversion of sunlight by photosynthetic organisms has changed Earth and life on it. | *<font face="Gill Sans MT">Energy conversion of sunlight by photosynthetic organisms has changed Earth and life on it. | ||
| Line 13: | Line 13: | ||
*An expanding wealth of genetic information, together with biochemical, biophysical, and physiological data, reveals a mosaic of photosynthetic features. | *An expanding wealth of genetic information, together with biochemical, biophysical, and physiological data, reveals a mosaic of photosynthetic features. | ||
*In combination, these data provide an increasingly robust framework to formulate and evaluate hypotheses concerning the origin and evolution of photosynthesis. </font> | *In combination, these data provide an increasingly robust framework to formulate and evaluate hypotheses concerning the origin and evolution of photosynthesis. </font> | ||
<br> | |||
<br> | |||
"'''Functional Evolution of Photochemical Energy Transformations in Oxygen-Producing Organisms'''"<ref name=raven2009/> | |||
*<font face="Gill Sans MT">Chlorophyll a is the photochemical agent accounting for most oxygenic photosynthesis, that is, over 99.9% of photosynthetic primary activity on Earth. | |||
*The spectral and energetic properties of chlorophyll a can, at least in part, be rationalised in terms of the solar spectral output and the energetics of oxygen production and carbon dioxide reduction with two photochemical reactions. | |||
*The long wavelength limit on in vivo chlorophyll a absorption is probably close to the energetic limit: longer wavelengths could not support a high rate and efficiency of oxygenic photosynthesis. | |||
*Retinal, a b-carotene derivative that is the chromophore of rhodopsin, acts not only as a sensory pigment, but also as an ion-pumping photochemical transducer. | |||
*Both sensory and energy-transforming rhodopsins occur in oxygenic phototrophs, although the extent of expression and the function of the latter are not well understood. </font> | |||
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<ref name=hm&b2011>Hohmann-Marriott MF, Blankenship RE. (2011) [http://dx.doi.org/10.1146/annurev-arplant-042110-103811 Evolution of Photosynthesis]. ''Annu. Rev. Plant Biol.'' 62:515–48.</ref> | <ref name=hm&b2011>Hohmann-Marriott MF, Blankenship RE. (2011) [http://dx.doi.org/10.1146/annurev-arplant-042110-103811 Evolution of Photosynthesis]. ''Annu. Rev. Plant Biol.'' 62:515–48.</ref> | ||
<ref name=raven2009>Raven JA. (2009) [http://dx.doi.org/10.1071/FP09087 Functional evolution of photochemical energy transformations in oxygen-producing organisms]. ''Functional Plant Biology''. 36:505515.</ref> | |||
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Latest revision as of 21:45, 27 August 2011
Selected article abstracts bulleted
Evolution of Photosynthesis
"Evolution of Photosynthesis"[1]
- Energy conversion of sunlight by photosynthetic organisms has changed Earth and life on it.
- Photosynthesis arose early in Earth’s history, and the earliest forms of photosynthetic life were almost certainly anoxygenic (non-oxygen evolving).
- The invention of oxygenic photosynthesis and the subsequent rise of atmospheric oxygen approximately 2.4 billion years ago revolutionized the energetic and enzymatic fundamentals of life.
- The repercussions of this revolution are manifested in novel biosynthetic pathways of photosynthetic cofactors and the modification of electron carriers, pigments, and existing and alternative modes of photosynthetic carbon fixation.
- The evolutionary history of photosynthetic organisms is further complicated by lateral gene transfer that involved photosynthetic components as well as by endosymbiotic events.
- An expanding wealth of genetic information, together with biochemical, biophysical, and physiological data, reveals a mosaic of photosynthetic features.
- In combination, these data provide an increasingly robust framework to formulate and evaluate hypotheses concerning the origin and evolution of photosynthesis.
"Functional Evolution of Photochemical Energy Transformations in Oxygen-Producing Organisms"[2]
- Chlorophyll a is the photochemical agent accounting for most oxygenic photosynthesis, that is, over 99.9% of photosynthetic primary activity on Earth.
- The spectral and energetic properties of chlorophyll a can, at least in part, be rationalised in terms of the solar spectral output and the energetics of oxygen production and carbon dioxide reduction with two photochemical reactions.
- The long wavelength limit on in vivo chlorophyll a absorption is probably close to the energetic limit: longer wavelengths could not support a high rate and efficiency of oxygenic photosynthesis.
- Retinal, a b-carotene derivative that is the chromophore of rhodopsin, acts not only as a sensory pigment, but also as an ion-pumping photochemical transducer.
- Both sensory and energy-transforming rhodopsins occur in oxygenic phototrophs, although the extent of expression and the function of the latter are not well understood.
References
- ↑ Hohmann-Marriott MF, Blankenship RE. (2011) Evolution of Photosynthesis. Annu. Rev. Plant Biol. 62:515–48.
- ↑ Raven JA. (2009) Functional evolution of photochemical energy transformations in oxygen-producing organisms. Functional Plant Biology. 36:505515.