Photosynthesis: Difference between revisions
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Generically, the biological process of '''photosynthesis''' | Generically, in the biological process of '''photosynthesis''', certain [[Organism|organisms]] (e.g., certain plants, algae and bacteria) capture the [[Energy|energy]] of the [[Photon|photons]] in sunlight, and through a series of reactions, transforms that radiant energy into the biochemical energy the organisms need to perform the cellular work that maintains them in the [[Life|living]] state. Nearly all living systems on Earth depend directly or indirectly on photosynthesis (see below), and for us humans it indirectly provides essentially all of our food and the bulk of our energy resources. | ||
In the prototypical form of the biological process of photosynthesis in green plants, the leaves capture energy from the photons in sunlight and use that captured energy as the essential primary energy source to drive a set of biochemical reactions that converts [[Carbon dioxide|carbon dioxide]] (CO<sub>2</sub>) and [[Water|water]] (H<sub>2</sub>O) to [[Oxygen|oxygen]] (O<sub>2</sub>) and a [[Carbohydrate|carbohydrate]] compound, [[triose]], a 3-carbon sugar. Triose phosphates exit the leaf cell's organelle where they are formed — the chloroplast — | In the prototypical form of the biological process of photosynthesis in green plants, the leaves capture energy from the photons in sunlight and use that captured energy as the essential primary energy source to drive a set of biochemical reactions that converts [[Carbon dioxide|carbon dioxide]] (CO<sub>2</sub>) and [[Water|water]] (H<sub>2</sub>O) to [[Oxygen|oxygen]] (O<sub>2</sub>) and a [[Carbohydrate|carbohydrate]] compound, [[triose]], a 3-carbon sugar.<ref>'''<u>Note:</u>''' Summary equations typically depict [[Glucose|glucose]]as the carbohydrate end-product of photosynthesis, whereas photosynthesizing cells generate very little glucose per se; the three-carbon trioses represent the more immediate photosynthetic carbohydrate.</ref>. Triose, as triose phosphates, exit the leaf cell's organelle where they are formed — the chloroplast — condensed into six-carbon [[Hexose|hexose]] phosphates and ultimately form sucrose, starch or cellulose. The process effectively stores energy in such sugar molecules that the photosynthetic organism can [[Metabolism|metabolize]] to generate [[Adenosine triphosphate|adenosine triphosphate]] (ATP), the universal energy currency of cells, so-called because it can provide the energy needed to drive biochemical reactions necessary to synthesize the macromolecules required to maintain the cell in a living state. Photosynthesizing cells thus convert light energy to the life-sustaining chemical energy that drives cellular processes. | ||
Organisms that photosynthesize, functioning as [[Autotrophs|autotrophs]] — organisms that generate their own source of food-energy — with their photon-energy-derived complement of carbohydrates, proteins and lipids, directly provide a source of food-energy (e.g., vegetables, fruits) for consumption by us humans and other organisms, so-called [[Heterotroph|heterotrophs]] — organisms that feed on other organisms or their components — and indirectly provide a source of food-energy in the form of the non-human heterotrophs that we consume (e.g., chickens, fish). Photosynthesizing cells also supply the oxygen we need to generate our own ATP, and they consume the 'waste' CO<sub>2</sub> produced in the process of generating ATP. | Organisms that photosynthesize, thereby functioning as [[Autotrophs|autotrophs]] — organisms that generate their own source of food-energy — with their ultimately produced photon-energy-derived complement of carbohydrates, proteins and lipids, directly provide a source of food-energy (e.g., vegetables, fruits) for consumption by us humans and other organisms, so-called [[Heterotroph|heterotrophs]] — organisms that feed on other organisms or their structural components — and indirectly provide a source of food-energy in the form of the non-human heterotrophs that we humans consume (e.g., chickens, fish). Photosynthesizing cells also supply the oxygen we need to generate our own ATP, and they consume the 'waste' CO<sub>2</sub> produced in the process of generating ATP. | ||
This article will classify the differing types of photosynthesizing organisms, and describe the details of the differing photosynthetic mechanisms employed by them. It will also discuss the implications of photosynthesis in the sciences of biology, geology, oceanography, climatology, and other areas of importance to the life of planet Earth. | This article will classify the differing types of photosynthesizing organisms, and describe the details of the differing photosynthetic mechanisms employed by them. It will also discuss the implications of photosynthesis in the sciences of biology, geology, oceanography, climatology, and other areas of importance to the life of planet Earth. | ||
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::*Origin and Evolution of Photosynthesis | ::*Origin and Evolution of Photosynthesis | ||
::*Light, Energy and Kinetics | ::*Light, Energy and Kinetics | ||
::*Index</ref> | ::*Index</ref> <ref name=raven1999>Raven PH, Evert RF, Eichhorn SE. (1999) Ohotosynthesis, Light, and Life. Chapter 7. In: Biology of Plants. 6th ed. New York: W.H. Freeman. ISBN 1-57259-041-6; ISBN 1-57259-611-2 (comp).</ref> | ||
==References Cited and Notes in Text== | ==References Cited and Notes in Text== | ||
<references/> | <references/> | ||
Revision as of 14:32, 23 August 2008
Generically, in the biological process of photosynthesis, certain organisms (e.g., certain plants, algae and bacteria) capture the energy of the photons in sunlight, and through a series of reactions, transforms that radiant energy into the biochemical energy the organisms need to perform the cellular work that maintains them in the living state. Nearly all living systems on Earth depend directly or indirectly on photosynthesis (see below), and for us humans it indirectly provides essentially all of our food and the bulk of our energy resources.
In the prototypical form of the biological process of photosynthesis in green plants, the leaves capture energy from the photons in sunlight and use that captured energy as the essential primary energy source to drive a set of biochemical reactions that converts carbon dioxide (CO2) and water (H2O) to oxygen (O2) and a carbohydrate compound, triose, a 3-carbon sugar.[1]. Triose, as triose phosphates, exit the leaf cell's organelle where they are formed — the chloroplast — condensed into six-carbon hexose phosphates and ultimately form sucrose, starch or cellulose. The process effectively stores energy in such sugar molecules that the photosynthetic organism can metabolize to generate adenosine triphosphate (ATP), the universal energy currency of cells, so-called because it can provide the energy needed to drive biochemical reactions necessary to synthesize the macromolecules required to maintain the cell in a living state. Photosynthesizing cells thus convert light energy to the life-sustaining chemical energy that drives cellular processes.
Organisms that photosynthesize, thereby functioning as autotrophs — organisms that generate their own source of food-energy — with their ultimately produced photon-energy-derived complement of carbohydrates, proteins and lipids, directly provide a source of food-energy (e.g., vegetables, fruits) for consumption by us humans and other organisms, so-called heterotrophs — organisms that feed on other organisms or their structural components — and indirectly provide a source of food-energy in the form of the non-human heterotrophs that we humans consume (e.g., chickens, fish). Photosynthesizing cells also supply the oxygen we need to generate our own ATP, and they consume the 'waste' CO2 produced in the process of generating ATP.
This article will classify the differing types of photosynthesizing organisms, and describe the details of the differing photosynthetic mechanisms employed by them. It will also discuss the implications of photosynthesis in the sciences of biology, geology, oceanography, climatology, and other areas of importance to the life of planet Earth.
Preliminarily, the reader might refer to the following: [2] [3] [4] [5] [6] [7]
References Cited and Notes in Text
- ↑ Note: Summary equations typically depict glucoseas the carbohydrate end-product of photosynthesis, whereas photosynthesizing cells generate very little glucose per se; the three-carbon trioses represent the more immediate photosynthetic carbohydrate.
- ↑ Farabee MJ. (2007) What is photosynthesis? Online Biology Book
- Detailed teatment of photosynthesis in an online biology course textbook. Includes an illustrated glossary.
- ↑ Photosynthesis Encyclopedia Britannica Free Full-Text Article
- ↑ John Whitmarsh, Govindjee. THE PHOTOSYNTHETIC PROCESS In: "Concepts in Photobiology: Photosynthesis and Photomorphogenesis", Edited by GS Singhal, G Renger, SK Sopory, K-D Irrgang and Govindjee, Narosa Publishers/New Delhi; and Kluwer Academic/Dordrecht, pp. 11-51. The online text is a revised and modified version of "Photosynthesis" by J. Whitmarsh and Govindjee (1995), published in Encyclopedia of Applied Physics (Vol. 13, pp. 513-532) by VCH Publishers, Inc.
- A comprehensive treatment of photosynthesis in a book chapter online. Includes history and research aspects. Detailed.
- ↑ Vermaas W. Introduction to Photosynthesis and Its Applications
- An introduction to photosynthesis readily accessible to the general reader.
- ↑ Blankenship RE. (2002) Molecular Mechanisms of Photosynthesis. Wiley-Blackwell. ISBN 0632043210 (ISBN-10); ISBN 978-0632043217 (ISBN-13) (pbk)
- Table of Contents:
- Preface
- Acknowledgments
- The Basic Principles of Photosynthetic Energy Storage
- Photosynthetic Organisms and Organelles
- History and Early Development of Photosynthesis
- Photosynthetic Pigments: Structure and Spectroscopy
- Antenna Complexes and Energy Transfer Processes
- Reaction Center Complexes
- Electron Transfer Pathways and Components
- Chemiosmotic Coupling and ATP Synthesis
- Carbon Metabolism
- Genetics, Assembly and Regulation of Photosynthetic Systems
- Origin and Evolution of Photosynthesis
- Light, Energy and Kinetics
- Index
- ↑ Raven PH, Evert RF, Eichhorn SE. (1999) Ohotosynthesis, Light, and Life. Chapter 7. In: Biology of Plants. 6th ed. New York: W.H. Freeman. ISBN 1-57259-041-6; ISBN 1-57259-611-2 (comp).