Phototroph
Phototrophs (from
2S
2O
3, as in some purple sulfur bacteria, or H
2S, as in some green sulfur bacteria) they can be also called lithotrophs, and so, some photoautotrophs are also called photolithoautotrophs. Examples of phototroph organisms are Rhodobacter capsulatus, Chromatium, and Chlorobium
History
Originally used with a different meaning, the term took its current definition after
Photoautotroph
Most of the well-recognized phototrophs are
Oxygenic photosynthetic organisms use chlorophyll for light-energy capture and oxidize water, "splitting" it into molecular oxygen.
Ecology
In an ecological context, phototrophs are often the food source for neighboring heterotrophic life. In terrestrial environments, plants are the predominant variety, while aquatic environments include a range of phototrophic organisms such as algae (e.g., kelp), other protists (such as euglena), phytoplankton, and bacteria (such as cyanobacteria).
Cyanobacteria, which are prokaryotic organisms which carry out oxygenic photosynthesis, occupy many environmental conditions, including fresh water, seas, soil, and lichen. Cyanobacteria carry out plant-like photosynthesis because the organelle in plants that carries out photosynthesis is derived from an[4] endosymbiotic cyanobacterium.[5] This bacterium can use water as a source of electrons in order to perform CO2 reduction reactions.
A photolithoautotroph is an
Photoheterotroph
In contrast to photoautotrophs, photoheterotrophs are organisms that depend solely on light for their energy and principally on organic compounds for their carbon. Photoheterotrophs produce ATP through photophosphorylation but use environmentally obtained organic compounds to build structures and other bio-molecules.[6]
Classification by light-capturing molecule
Most phototrophs use chlorophyll or the related bacteriochlorophyll to capture light and are known as chlorophototrophs. Others, however, use retinal and are retinalophototrophs.[7]
Flowchart
Energy source Carbon source |
Chemotroph | Phototroph |
---|---|---|
Autotroph | Chemoautotroph |
Photoautotroph |
Heterotroph | Chemoheterotroph |
Photoheterotroph |
See also
- Primary nutritional groups
- Prototroph
References
- ^ Lwoff, A., C.B. van Niel, P.J. Ryan, and E.L. Tatum (1946). Nomenclature of nutritional types of microorganisms. Cold Spring Harbor Symposia on Quantitative Biology (5th edn.), Vol. XI, The Biological Laboratory, Cold Spring Harbor, NY, pp. 302–303, [1].
- ^ Schneider, С. K. 1917. Illustriertes Handwörterbuch der Botanik. 2. Aufl., herausgeg. von K. Linsbauer. Leipzig: Engelmann, [2].
- ISBN 978-0-8160-5648-4.
- ^ Hill, Malcolm S. "Production Possibility Frontiers in Phototroph:heterotroph Symbioses: Trade-Offs in Allocating Fixed Carbon Pools and the Challenges These Alternatives Present for Understanding the Acquisition of Intracellular Habitats." Frontiers in Microbiology 5 (2014): 357. PMC. Web. 11 March 2016.
- ^ 3. Johnson, Lewis, Morgan, Raff, Roberts, and Walter. "Energy Conversion: Mitochondria and Chloroplast." Molecular Biology of the Cell, Sixth Edition By Alberts. 6th ed. New York: Garland Science, Taylor & Francis Group, 2015. 774+. Print.
- ISBN 978-0-8053-6844-4.
- PMID 31457093.