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Photosynthesis splits water to liberate O₂ and fixes CO₂ into sugar

The leaf is the primary site of photosynthesis in plants.

Photosynthesis is the conversion of light energy into chemical energy by living organisms. The raw materials are carbon dioxide and water; the energy source is sunlight; and the end-products are oxygen and (energy rich) carbohydrates, for example sucrose, glucose and starch. This process is arguably the most important biochemical pathway,^[1] since nearly all life either directly or indirectly depends on it. It is a complex process occurring in higher plants, phytoplankton, algae, as well as bacteria such as cyanobacteria. Photosynthetic organisms are also referred to as photoautotrophs.^[1] Image File history File links Question_book-3. ... Image File history File links Download high-resolution version (1024x768, 158 KB) Leaf1. ... Image File history File links Download high-resolution version (1024x768, 158 KB) Leaf1. ... Look up foliage in Wiktionary, the free dictionary. ... For other uses, see Light (disambiguation). ... In chemistry, a chemical bond is the force which holds together atoms in molecules or crystals. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... This article is about the chemical element and its most stable form, or dioxygen. ... Lactose is a disaccharide found in milk. ... Flash point N/A Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Sucrose (common name: table sugar, also called saccharose) is a disaccharide (glucose + fructose) with the molecular formula C12H22O11. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell, catalyzed by enzymes, resulting in either the formation of a metabolic product to be used or stored by the cell, or the initiation of another metabolic pathway (then called a flux generating step). ... For other uses, see Plant (disambiguation). ... Diagrams of some typical phytoplankton Phytoplankton are the autotrophic component of plankton. ... Osborne (talk) 20:17, 5 December 2007 (UTC):For the programming language, see algae (programming language) Laurencia, a marine red alga from Hawaii. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Orders The taxonomy is currently under revision. ... Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ...

The word comes from the Greek photo-, "light", and synthesis, "putting together".

Overview

Photosynthesis uses light energy and carbon dioxide to make triose phospates (G3P). G3P is generally considered the prime end-product of photosynthesis. It can be used as an immediate food nutrient, or combined and rearranged to form disaccharide sugars, such as sucrose and fructose, which can be transported to other cells, or packaged for storage as insoluble polysaccharides such as starch. G3P (structure) Glyceraldehyde 3-phosphate (G3P) is an intermediate in both glycolysis and gluconeogenesis. ... Sucrose, a common disaccharide A disaccharide is a sugar (a carbohydrate) composed of two monosaccharides. ... Flash point N/A Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Sucrose (common name: table sugar, also called saccharose) is a disaccharide (glucose + fructose) with the molecular formula C12H22O11. ... Fructose (or levulose) is a simple sugar (monosaccharide) found in many foods and is one of the three most important blood sugars along with glucose and galactose. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ...

A commonly used but slightly simplified equation for photosynthesis is: A chemical equation is a symbolic representation of a chemical reaction. ...

6 CO_2(g) + 12 H₂O_(l) + photons → C₆H₁₂O_6(aq) + 6 O_2(g) + 6 H₂O_(l)

carbon dioxide + water + light energy → glucose + oxygen + water

When written as a word equation the light energy appears above the arrow as it is required for photosynthesis but it is not actually a reactant. Here the monosaccharide glucose is shown as a product, although the actual processes in plants produce disaccharides. In physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field; for instance, light. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... Monosaccharides are the simplest form of carbohydrates. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ...

The equation is often presented in introductory chemistry texts in an even more simplified form as:^[2]

6 CO_2(g) + 6 H₂O_(l) + photons → C₆H₁₂O_6(aq) + 6 O_2(g)

Photosynthesis occurs in two stages. In the first phase, light-dependent reactions or photosynthetic reactions (also called the Light reactions) capture the energy of light and use it to make high-energy molecules. During the second phase, the light-independent reactions (also called the Calvin-Benson Cycle, and formerly known as the Dark Reactions) use the high-energy molecules to capture carbon dioxide (CO₂) and make the precursors of carbohydrates. In physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field; for instance, light. ... Overview of the Calvin cycle and carbon fixation The Calvin cycle (or Calvin-Benson cycle or carbon fixation) is a series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... In chemistry a precursor is a compound that participates in the chemical reaction that produces another compound. ... Lactose is a disaccharide found in milk. ...

In the light reactions, one molecule of the pigment chlorophyll absorbs one photon and loses one electron. This electron is passed to a modified form of chlorophyll called pheophytin, which passes the electron to a quinone molecule, allowing the start of a flow of electrons down an electron transport chain that leads to the ultimate reduction of NADP into NADPH. In addition, it serves to create a proton gradient across the chloroplast membrane; its dissipation is used by ATP Synthase for the concomitant synthesis of ATP. The chlorophyll molecule regains the lost electron by taking one from a water molecule through a process called photolysis, that releases oxygen gas. The first stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... Natural Ultramarine pigment in powdered form. ... Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... For other uses, see Electron (disambiguation). ... Pheophytin is an accessory pigment in photosystemII of the electron transport chain associated with photosynthesis. ... A quinone (or benzoquinone) is either one of the two isomers of cyclohexadienedione or a derivative thereof. ... The Electron Transport Chain. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... An ion gradient is a concentration gradient of ions, it can be called an electrochemical potential gradient of ions across membranes. ... Chloroplasts contain several important membranes, vital for their function. ... An ATP synthase (EC 3. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Photolysis refers to any chemical reaction in which a compound is broken down by light. ... This article is about the chemical element and its most stable form, or dioxygen. ...

In the Light-independent or dark reactions the enzyme RuBisCO captures CO₂ from the atmosphere and in a process that requires the newly-formed NADPH, called the Calvin-Benson cycle releases three-carbon sugars, which are later combined to form sucrose and starch. Overview of the Calvin cycle and carbon fixation In photosynthesis, the light-independent reactions, also somewhat misleadingly called the dark reactions (they dont require darkness, but they do require the products of the light reactions), are chemical reactions that convert carbon dioxide and other compounds into glucose. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Ribulose-1,5-bisphosphate carboxylase/oxygenase, most commonly known by the shorter name RuBisCO, is an enzyme (EC 4. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Air redirects here. ... The Calvin cycle (also known as Calvin-Benson cycle) is a series of biochemical reactions taking place in the chloroplasts of photosynthetic organisms. ...

Photosynthesis may simply be defined as the conversion of light energy into chemical energy by living organisms. It is affected by its surroundings and the rate of photosynthesis is affected by the concentration of carbon dioxide, the intensity of light, and the temperature. Willard Gibbs - founder of chemical thermodynamics In thermodynamics, chemical thermodynamics is the mathematical study of the interrelation of heat and work with chemical reactions or with a physical change of state within the confines of the laws of thermodynamics. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... For other uses, see Temperature (disambiguation). ...

In plants

Most plants are photoautotrophs, which means that they are able to synthesize food directly from inorganic compounds using light energy - for example from the sun, instead of eating other organisms or relying on nutrients derived from them. This is distinct from chemoautotrophs that do not depend on light energy, but use energy from inorganic compounds. Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ... In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. ... Traditionally, inorganic compounds are considered to be of mineral, not biological, origin. ... Chemotrophs are organisms that obtain energy by the oxidation of electron donating molecules in their environments. ...

6 CO₂ + 12 H₂O → C₆H₁₂O₆ + 6 O₂ + 6 H₂O

The energy for photosynthesis ultimately comes from absorbed photons and involves a reducing agent, which is water in the case of plants, releasing oxygen as a waste product. The light energy is converted to chemical energy (known as light-dependent reactions), in the form of ATP and NADPH, which are used for synthetic reactions in photoautotrophs. The overall equation for the light-dependent reactions under the conditions of non-cyclic electron flow in green plants is: In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... This article is about the chemical element and its most stable form, or dioxygen. ... Light-dependent reactions of photosynthesis at the thylakoid membrane The initial stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ...

2 H₂O + 2 NADP⁺ + 2 ADP + 2 P_i + light → 2 NADPH + 2 H⁺ + 2 ATP + O₂ ^[3]

Most notably, plants use the chemical energy to fix carbon dioxide into carbohydrates and other organic compounds through light-independent reactions. The overall equation for carbon fixation (sometimes referred to as carbon reduction) in green plants is: Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Lactose is a disaccharide found in milk. ... Overview of the Calvin cycle and carbon fixation In photosynthesis, the light-independent reactions, also somewhat misleadingly called the dark reactions (they dont require darkness, but they do require the products of the light reactions), are chemical reactions that convert carbon dioxide and other compounds into glucose. ...

3 CO₂ + 9 ATP + 6 NADPH + 6 H⁺ → C₃H₆O₃-phosphate + 9 ADP + 8 P_i + 6 NADP⁺ + 3 H₂O ^[3]

To be more specific, carbon fixation produces an intermediate product, which is then converted to the final carbohydrate products. The carbon skeletons produced by photosynthesis are then variously used to form other organic compounds, such as the building material cellulose, as precursors for lipid and amino acid biosynthesis, or as a fuel in cellular respiration. The latter occurs not only in plants but also in animals when the energy from plants gets passed through a food chain. Organisms dependent on photosynthetic and chemosynthetic organisms are called heterotrophs. In general outline, cellular respiration is the opposite of photosynthesis: Glucose and other compounds are oxidized to produce carbon dioxide, water, and chemical energy. However, both processes take place through a different sequence of chemical reactions and in different cellular compartments. Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... Some common lipids. ... This article is about the class of chemicals. ... Cellular respiration was discovered by mad scientist Mr. ... For other uses, see Animal (disambiguation). ... Food chains, food webs and/or food networks describe the feeding relationships between species to another within an ecosystem. ... Chemosynthesis is the biological conversion of 1 or more carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e. ... Flowchart to determine if a species is autotroph, heterotroph, or a subtype A heterotroph (Greek heterone = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development. ...

Plants absorb light primarily using the pigment chlorophyll, which is the reason that most plants have a green color. The function of chlorophyll is often supported by other accessory pigments such as carotenes and xanthophylls. Both chlorophyll and accessory pigments are contained in organelles (compartments within the cell) called Chloroplasts. Although all cells in the green parts of a plant have chloroplasts, most of the energy is captured in the leaves. The cells in the interior tissues of a leaf, called the mesophyll, can contain between 450,000 and 800,000 chloroplasts for every square millimeter of leaf. The surface of the leaf is uniformly coated with a water-resistant waxy cuticle that protects the leaf from excessive evaporation of water and decreases the absorption of ultraviolet or blue light to reduce heating. The transparent epidermis layer allows light to pass through to the palisade mesophyll cells where most of the photosynthesis takes place. Natural Ultramarine pigment in powdered form. ... Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... An accessory pigment is a pigment other than chlorophyll found in plants, such as a carotenoid, that serves the function of absorbing light energy, and transfering it to chlorophyll. ... β-Carotene represented by a 3-dimensional stick diagram Carotene is responsible for the orange colour of the carrots and many other fruits and vegetables. ... This article or section does not cite its references or sources. ... Schematic of typical animal cell, showing subcellular components. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... Look up foliage in Wiktionary, the free dictionary. ... This article is about the leaf, a plant organ. ... candle wax This page is about the substance. ... Plant cuticles are a protective waxy covering produced only by the epidermal cells (Kolattukudy, 1996) of leaves, young shoots and all other aerial plant organs. ... Vaporization redirects here. ... For other uses, see Ultraviolet (disambiguation). ... This article is about the colour. ... For other uses, see Light (disambiguation). ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Look up foliage in Wiktionary, the free dictionary. ... Look up foliage in Wiktionary, the free dictionary. ...

Plants use up to 90% of the light that strikes them, whereas commercial solar panels use less than 30%. This is achieved by groups of chlorophyll molecules spending a long time in a superposition of states.^[4] Quantum superposition is the application of the superposition principle to quantum mechanics. ...

In algae and bacteria

Algae come in multiple forms from multicellular organisms like kelp, to microscopic, single-cell organisms. Although they are not as complex as land plants, the biochemical process of photosynthesis is the same. Very much like plants, algae have chloroplasts and chlorophyll, but various accessory pigments are present in some algae such as phycocyanin, carotenes, and xanthophylls in green algae and phycoerythrin in red algae (rhodophytes), resulting in a wide variety of colors. All algae produce oxygen, and many are autotrophic. However, some are heterotrophic, relying on materials produced by other organisms. For example, in coral reefs, there is a mutualistic relationship between zooxanthellae and the coral polyps.^[5] Families Alariaceae Chordaceae Laminariaceae Lessoniaceae Phyllariaceae Pseudochordaceae Percentages are relative to US recommendations for adults. ... Microscopy is any technique for producing visible images of structures or details too small to otherwise be seen by the human eye, using a microscope or other magnification tool. ... A cluster of Escherichia coli bacteria magnified 10,000 times. ... An accessory pigment is a pigment other than chlorophyll found in plants, such as a carotenoid, that serves the function of absorbing light energy, and transfering it to chlorophyll. ... Phycocyanin is a pigment that is blue and is readily found in blue-green algae. ... β-Carotene represented by a 3-dimensional stick diagram Carotene is responsible for the orange colour of the carrots and many other fruits and vegetables. ... This article or section does not cite its references or sources. ... Divisions Chlorophyta Charophyta Green algae are microscopic protists; found in all aquatic environments, including marine, freshwater and brackish water. ... Phycoerythrin is a red protein from the light-harvesting phycobiliproteins family, isolated from red, blue-green, and crytomonad algae. ... Possible classes Florideophyceae Bangiophyceae Cyanidiophyceae The red algae (Rhodophyta, IPA: , from Greek: (rhodon) = rose + (phyton) = plant, thus red plant) are a large group, about 5,000–6,000 species [1] of mostly multicellular, marine algae, including many notable seaweeds. ... Green (from chlorophyll) fronds of a maidenhair fern: a photoautotroph Flowchart to determine if a species is autotroph, heterotroph, or a subtype An autotroph (from the Greek autos = self and trophe = nutrition) is an organism that produces complex organic compounds from simple inorganic molecules and an external source of energy... Some of the biodiversity of a coral reef, in this case the Great Barrier Reef, Australia. ... In biology, mutualism is an interaction between two or more species, where both species derive benefit. ... Zooxanthellae are golden-brown intracellular endosymbionts of various marine animals and protozoa, especially anthozoans. ... Anatomy of a coral polyp. ...

Photosynthetic bacteria do not have chloroplasts (or any membrane-bound organelles). Instead, photosynthesis takes place directly within the cell. Cyanobacteria contain thylakoid membranes very similar to those in chloroplasts and are the only prokaryotes that perform oxygen-generating photosynthesis. In fact, chloroplasts are now considered to have evolved from an endosymbiotic bacterium, which was also an ancestor of and later gave rise to cyanobacterium. The other photosynthetic bacteria have a variety of different pigments, called bacteriochlorophylls, and do not produce oxygen. Some bacteria, such as Chromatium, oxidize hydrogen sulfide instead of water for photosynthesis, producing sulfur as waste. Schematic of typical animal cell, showing subcellular components. ... Orders The taxonomy is currently under revision. ... A thylakoid is a phospholipid bilayer membrane internal to chloroplasts. ... This article is about evolution in biology. ... An endosymbiont (also known as intracellular symbiont) is any organism that lives within cells of another organism, i. ... Bacteriochlorophylls are photosynthetic pigments that occur in various bacteria. ... Type species Chromatium okenii Species C. okenii The Chromatium are a Gram-negative bacterium found in water. ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ... This article is about the chemical element. ...

Evolution

Plant cells with visible chloroplasts.

The ability to convert light energy to chemical energy confers a significant evolutionary advantage to living organisms. Early photosynthetic systems, such as those from green and purple sulfur and green and purple non-sulfur bacteria, are thought to have been anoxygenic, using various molecules as electron donors. Green and purple sulfur bacteria are thought to have used hydrogen and sulfur as an electron donor. Green nonsulfur bacteria used various amino and other organic acids. Purple nonsulfur bacteria used a variety of non-specific organic molecules. The use of these molecules is consistent with the geological evidence that the atmosphere was highly reduced at that time.^{[citation needed]} Image File history File linksMetadata No higher resolution available. ... For other uses, see Natural selection (disambiguation). ... Green sulfur bacteria - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Families Chromatiaceae Ectothiorhodospiraceae Halothiobacillaceae The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. ... Orders / Families / Genera Order Chloroflexales     Family Chloroflexaceae      Chloroflexus      Chloronema      Heliothrix      Roseiflexus    Family Oscillochloridaceae      Oscillochloris Order Herpetosiphonales      Herpetosiphon Order Dehalococcoidetes       Dehalococcoides The Chloroflexi are a group of bacteria that produce energy through photosynthesis. ... Purple bacteria or purple photosynthetic bacteria are proteobacteria that are phototrophic, i. ... An electron donor is a compound that gives up or donates an electron during cellular respiration, resulting in the release of energy. ... This article is about the chemistry of hydrogen. ... This article is about the chemical element. ... This article is about the class of chemicals. ... An organic acid is an organic compound that is an acid. ... A reducing environment is one chacterized by little or no free oxygen (dissolved or as a gas). ... Geological time put in a diagram called a geological clock, showing the relative lengths of the eons of the Earths history. ...

Fossils of what are thought to be filamentous photosynthetic organisms have been dated at 3.4 billion years old.^[6] Filaments surrounding a solar flare, caused by the interaction of the plasma in the Suns atmopshere with its magnetic field. ...

Oxygen in the atmosphere exists due to the evolution of oxygenic photosynthesis, sometimes referred to as the oxygen catastrophe. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor which is oxidized into molecular oxygen by the absorption of a photon by the photosynthetic reaction center. This article is about the chemical element and its most stable form, or dioxygen. ... Air redirects here. ... Oxygen evolution is the process of generating molecular oxygen through chemical reaction. ... The Oxygen Catastrophe was a massive environmental change believed to have happened during the Siderian period at the beginning of the Paleoproterozoic era. ... Orders The taxonomy is currently under revision. ... The Paleoproterozoic is the first of the three sub-divisions of the Proterozoic occurring between 2500 to 1600 million years ago. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... In the process of photosynthesis, light is absorbed by a photosystem (ancient Greek: phos = light and systema = assembly) to begin an energy-producing reaction. ...

Origin of chloroplasts

In plants the process of photosynthesis occurs in organelles called chloroplasts. Chloroplasts have many similarities with photosynthetic bacteria including a circular chromosome, prokaryotic-type ribosomes, and similar proteins in the photosynthetic reaction center. Schematic of typical animal cell, showing subcellular components. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... Orders The taxonomy is currently under revision. ... A scheme of a condensed (metaphase) chromosome. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ...

The endosymbiotic theory suggests that photosynthetic bacteria were acquired (by endocytosis or gene fusion) by early eukaryotic cells to form the first plant cells. In other words, chloroplasts may simply be primitive photosynthetic bacteria adapted to life inside plant cells, whereas plants themselves have not actually evolved photosynthetic processes on their own. Another example of this can be found in complex animals, including humans, whose cells depend upon mitochondria as their energy source; mitochondria are thought to have evolved from endosymbiotic bacteria, related to modern Rickettsia bacteria. Both chloroplasts and mitochondria actually have their own DNA, separate from the nuclear DNA of their animal or plant host cells. The endosymbiotic theory concerns the origins of mitochondria and plastids (e. ... Endocytosis (IPA: ) is a process whereby cells absorb material (molecules such as proteins) from the outside by engulfing it with their cell membrane. ... Gene-Fusion is a 26 part animated television series produced by Banjax based on an original comic from Beckett Entertainment. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... For other uses, see Plant (disambiguation). ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Species Rickettsia felis Rickettsia prowazekii Rickettsia rickettsii Rickettsia typhi Rickettsia conorii Rickettsia africae etc. ...

This contention is supported by the finding that the marine molluscs Elysia viridis and Elysia chlorotica seem to maintain a symbiotic relationship with chloroplasts from algae with similar RDA structures that they encounter. However, they do not transfer these chloroplasts to the next generations. Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia † Helcionelloida † ?Bellerophontida The molluscs (British spelling) or mollusks (American spelling) are members of the very large and diverse phylum Mollusca. ... Binomial name Elysia viridis Elysia viridis is a sea slug gastropod mollusc that lives in a subcellular endosymbiotic relationship with chloroplasts of the alga Codium fragile. ... Binomial name Elysia chlorotica Elysia chlorotica Gould is a littoral sea slug that lives in a subcellular endosymbiotic relationship with chloroplasts of the marine heterokont alga Vaucheria litorea C. Agardh, which provide their host with the products of photosynthesis. ... For other uses, see Symbiosis (disambiguation). ...

Cyanobacteria and the evolution of photosynthesis

The biochemical capacity to use water as the source for electrons in photosynthesis evolved once, in a common ancestor of extant cyanobacteria. The geological record indicates that this transforming event took place early in our planet's history, at least 2450-2320 million years ago (Ma), and possibly much earlier. Geobiological interpretation of Archean (>2500 Ma) sedimentary rocks remains a challenge; available evidence indicates that life existed 3500 Ma, but the question of when oxygenic photosynthesis evolved continues to engender debate and research. A clear paleontological window on cyanobacterial evolution opened about 2000 Ma, revealing an already-diverse biota of blue-greens. Cyanobacteria remained principal primary producers throughout the Proterozoic Eon (2500-543 Ma), in part because the redox structure of the oceans favored photautotrophs capable of nitrogen fixation. Green algae joined blue-greens as major primary producers on continental shelves near the end of the Proterozoic, but only with the Mesozoic (251-65 Ma) radiations of dinoflagellates, coccolithophorids, and diatoms did primary production in marine shelf waters take modern form. Cyanobacteria remain critical to marine ecosystems as primary producers in oceanic gyres, as agents of biological nitrogen fixation, and, in modified form, as the plastids of marine algae.^[7] Orders The taxonomy is currently under revision. ... The Archean is a geologic eon; it is a somewhat antiquated term for the time span between 2500 million years before the present and 3800 million years before the present. ... This article is about evolution in biology. ... Orders The taxonomy is currently under revision. ... The Proterozoic (IPA: ) is a geological eon representing a period before the first abundant complex life on Earth. ... Nitrogen fixation is the process by which nitrogen is taken from its natural, relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds (such as, notably, ammonia, nitrate and nitrogen dioxide)[1] useful for other chemical processes. ... Divisions Chlorophyta Charophyta Green algae are microscopic protists; found in all aquatic environments, including marine, freshwater and brackish water. ... The Proterozoic (IPA: ) is a geological eon representing a period before the first abundant complex life on Earth. ... The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. ...

Molecular production

Light-dependent reactions of photosynthesis at the thylakoid membrane

Image File history File links Size of this preview: 800 × 456 pixel Image in higher resolution (905 × 516 pixel, file size: 82 KB, MIME type: image/png) Light-dependent reactions of photosynthesis at the thylakoid membrane. ... Image File history File links Size of this preview: 800 × 456 pixel Image in higher resolution (905 × 516 pixel, file size: 82 KB, MIME type: image/png) Light-dependent reactions of photosynthesis at the thylakoid membrane. ...

Light to chemical energy

Main article: Light-dependent reaction

The light energy is converted to chemical energy using the light-dependent reactions. This chemical energy production is more than 90% efficient with only 5-8% of the energy transferred thermally. The products of the light-dependent reactions are ATP from photophosphorylation and NADPH from photoreduction. Both are then utilized as an energy source for the light-independent reactions. Light-dependent reactions of photosynthesis at the thylakoid membrane The initial stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... Light-dependent reactions of photosynthesis at the thylakoid membrane The initial stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... Light-dependent reactions of photosynthesis at the thylakoid membrane The initial stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... The production of ATP using the energy of sunlight is called photophosphorylation. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... Overview of the Calvin cycle and carbon fixation In photosynthesis, the light-independent reactions, also somewhat misleadingly called the dark reactions (they dont require darkness, but they do require the products of the light reactions), are chemical reactions that convert carbon dioxide and other compounds into glucose. ...

Not all wavelengths of light can support photosynthesis. The photosynthetic action spectrum depends on the type of accessory pigments present. For example, in green plants, the action spectrum resembles the absorption spectrum for chlorophylls and carotenoids with peaks for violet-blue and red light. In red algae, the action spectrum overlaps with the absorption spectrum of phycobilins for blue-green light, which allows these algae to grow in deeper waters that filter out the longer wavelengths used by green plants. The non-absorbed part of the light spectrum is what gives photosynthetic organisms their color (e.g., green plants, red algae, purple bacteria) and is the least effective for photosynthesis in the respective organisms. For other uses, see Wavelength (disambiguation). ... An accessory pigment is a pigment other than chlorophyll found in plants, such as a carotenoid, that serves the function of absorbing light energy, and transfering it to chlorophyll. ... An action spectrum is the rate of a physiological activity plotted against wavelength of light. ... A materials absorption spectrum shows the fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies. ... Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... The orange ring surrounding Grand Prismatic Spring is due to carotenoid molecules, produced by huge mats of algae and bacteria. ... Phycobilins are the chromophores of phycobiliproteins (photosynthetic pigments) found in cyanobacteria and in the chloroplasts of red algae, glaucophytes and some cryptomonads (though not in green algae and higher plants). ...

Z scheme

A Photosystem: A light-harvesting cluster of photosynthetic pigments present in the thylakoid membrane of chloroplasts.

The "Z scheme"

In plants, light-dependent reactions occur in the thylakoid membranes of the chloroplasts and use light energy to synthesize ATP and NADPH. The light-dependent reaction has two forms; cyclic and non-cyclic reaction. In the non-cyclic reaction, the photons are captured in the light-harvesting antenna complexes of photosystem II by chlorophyll and other accessory pigments (see diagram at right). When a chlorophyll molecule at the core of the photosystem II reaction center obtains sufficient excitation energy from the adjacent antenna pigments, an electron is transferred to the primary electron-acceptor molecule, Pheophytin, through a process called Photoinduced charge separation. These electrons are shuttled through an electron transport chain, the so called Z-scheme shown in the diagram, that initially functions to generate a chemiosmotic potential across the membrane. An ATP synthase enzyme uses the chemiosmotic potential to make ATP during photophosphorylation, whereas NADPH is a product of the terminal redox reaction in the Z-scheme. The electron enters the Photosystem I molecule. The electron is excited due to the light absorbed by the photosystem. A second electron carrier accepts the electron, which again is passed down lowering energies of electron acceptors. The energy created by the electron acceptors is used to move hydrogen ions across the thylakoid membrane into the lumen. The electron is used to reduce the co-enzyme NADP, which has functions in the light-independent reaction. The cyclic reaction is similar to that of the non-cyclic, but differs in the form that it generates only ATP, and no reduced NADP (NADPH) is created. The cyclic reaction takes place only at photosystem I. Once the electron is displaced from the photosystem, the electron is passed down the electron acceptor molecules and returns back to photosystem I, from where it was emitted, hence the name cyclic reaction. Image File history File links Photosystems. ... Image File history File links Photosystems. ... Download high resolution version (905x281, 36 KB)Z-scheme File links The following pages link to this file: Light-dependent reaction Categories: GFDL images ... Download high resolution version (905x281, 36 KB)Z-scheme File links The following pages link to this file: Light-dependent reaction Categories: GFDL images ... Light-dependent reactions of photosynthesis at the thylakoid membrane The initial stage of the photosynthetic system is the light-dependent reaction, which converts solar energy into chemical energy. ... A thylakoid is a phospholipid bilayer membrane internal to chloroplasts. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... The antenna complex is an array of chlorophyll molecules embedded in the thylakoid membrane that transfer energy to a pair of chlorophyll a molecules at the reaction center of a photosystem. ... REDIRECT [[In the process of photosynthesis, light is absorbed by a photosystem (ancient Greek: phos = light and systema = assembly) to begin an energy-producing reaction. ... Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... Chlorophyll gives leaves their green colour Chlorophyll is a green photosynthetic pigment found in plants, algae, and cyanobacteria. ... Photoinduced charge separation is the process of an electron in an atom being excited to a higher energy level and then leaving the atom to a nearby electron acceptor. ... The electron transfer chain (also called the electron transport chain, ETC, e-train, or simply electron transport), is any series of protein complexes and lipid-soluble messengers that convert the reductive potential of energized electrons into a cross-membrane proton gradient. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... An ATP synthase (EC 3. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are two important coenzymes found in cells. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. ...

Water photolysis

Main articles: Photodissociation and Oxygen evolution

The NADPH is the main reducing agent in chloroplasts, providing a source of energetic electrons to other reactions. Its production leaves chlorophyll with a deficit of electrons (oxidized), which must be obtained from some other reducing agent. The excited electrons lost from chlorophyll in photosystem I are replaced from the electron transport chain by plastocyanin. However, since photosystem II includes the first steps of the Z-scheme, an external source of electrons is required to reduce its oxidized chlorophyll a molecules. The source of electrons in green-plant and cyanobacterial photosynthesis is water. Two water molecules are oxidized by four successive charge-separation reactions by photosystem II to yield a molecule of diatomic oxygen and four hydrogen ions; the electron yielded in each step is transferred to a redox-active tyrosine residue that then reduces the photoxidized paired-chlorophyll a species called P680 that serves as the primary (light-driven) electron donor in the photosystem II reaction center. The oxidation of water is catalyzed in photosystem II by a redox-active structure that contains four manganese ions; this oxygen-evolving complex binds two water molecules and stores the four oxidizing equivalents that are required to drive the water-oxidizing reaction. Photosystem II is the only known biological enzyme that carries out this oxidation of water. The hydrogen ions contribute to the transmembrane chemiosmotic potential that leads to ATP synthesis. Oxygen is a waste product of light-independent reactions, but the majority of organisms on Earth use oxygen for cellular respiration, including photosynthetic organisms. Photodissociation is the breakup of molecules caused by exposure to photons. ... Oxygen evolution is the process of generating molecular oxygen through chemical reaction. ... A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. ... Plastocyanin is a single strand protein of the thylakoid membrane, (molecular weight 10,500), that plays an integral part in photosynthesis. ... This article is about the chemical element and its most stable form, or dioxygen. ... This article is about the chemistry of hydrogen. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells... Catalyst redirects here. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... Oxygen evolution is the process of generating molecular oxygen through chemical reaction. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Cellular respiration was discovered by mad scientist Mr. ...

Quantum mechanical effects

Through photosynthesis, sunlight energy is transferred to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. The transfer of the solar energy takes place almost instantaneously, so little energy is wasted as heat. However, only 43% of the total solar incident radiation can be used (only light in the range 400-700 nm), 20% of light is blocked by canopy, and plant respiration requires about 33% of the stored energy, which brings down the actual efficiency of photosynthesis to about 6.6%^[8].

A study led by researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley suggests that long-lived wavelike electronic quantum coherence plays an important part in this instantaneous transfer of energy by allowing the photosynthetic system to simultaneously try each potential energy pathway and choose the most efficient option. Results of the study are presented in the April 12, 2007 issue of the journal Nature.^[9] The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... The Ernest Orlando Lawrence Berkeley National Laboratory (LBNL), formerly the Berkeley Radiation Laboratory and usually shortened to Berkeley Lab or LBL, is a U.S. Department of Energy (DOE) national laboratory conducting unclassified scientific research. ... The University of California, Berkeley (also known as Cal, UC Berkeley, UCB, or simply Berkeley) is a prestigious, public, coeducational university situated in the foothills of Berkeley, California to the east of San Francisco Bay, overlooking the Golden Gate and its bridge. ... Quantum coherence refers to the condition of a quantum system whose constituents are in-phase. ... Nature is a prominent scientific journal, first published on 4 November 1869. ...

Oxygen and photosynthesis

With respect to oxygen and photosynthesis, there are two important concepts.

• Plant and cyanobacterial (blue-green algae) cells also use oxygen for cellular respiration, although they have a net output of oxygen since much more is produced during photosynthesis.
• Oxygen is a product of the light-driven water-oxidation reaction catalyzed by photosystem II; it is not generated by the fixation of carbon dioxide. Consequently, the source of oxygen during photosynthesis is water, not carbon dioxide.

Orders The taxonomy is currently under revision. ...

Bacterial variation

The concept that oxygen production is not directly associated with the fixation of carbon dioxide was first proposed by Cornelis Van Niel in the 1930s, who studied photosynthetic bacteria. Aside from the cyanobacteria, bacteria only have one photosystem and use reducing agents other than water. They get electrons from a variety of different inorganic chemicals including sulfide or hydrogen, so for most of these bacteria oxygen is not produced. The concept that oxygen production is not directly associated with the fixation of carbon dioxide was first proposed by Cornelis Van Niel in the 1930s, who studied photosynthetic bacteria. ... Orders The taxonomy is currently under revision. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... This article is about the chemistry of hydrogen. ...

Others, such as the halophiles (an Archaea), produced so-called purple membranes where the bacteriorhodopsin could harvest light and produce energy. The purple membranes was one of the first to be used to demonstrate the chemiosmotic theory: light hit the membranes and the pH of the solution that contained the purple membranes dropped as protons were pumping out of the membrane. Halophiles are extremophiles that thrive in environments with very high concentrations of salt (at least 2 M, approximately ten times the salt level of ocean water). ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (pronounced ) are a group of prokaryotic and single-celled microorganisms. ... Bacteriorhodopsin is a photosynthetic pigment used by archaea, most notably halobacteria. ... Chemiosmosis is the diffusion of ions across a membrane. ...

Overview of the Calvin cycle and carbon fixation

Image File history File links Download high resolution version (856x742, 51 KB)This image was copied from wikipedia:en. ... Image File history File links Download high resolution version (856x742, 51 KB)This image was copied from wikipedia:en. ...

Carbon fixation

Main articles: Carbon fixation and Light-independent reaction

The fixation or reduction of carbon dioxide is a light-independent process in which carbon dioxide combines with a five-carbon sugar, ribulose 1,5-bisphosphate (RuBP), to yield two molecules of a three-carbon compound, glycerate 3-phosphate (GP), also known as 3-phosphoglycerate (PGA). GP, in the presence of ATP and NADPH from the light-dependent stages, is reduced to glyceraldehyde 3-phosphate (G3P). This product is also referred to as 3-phosphoglyceraldehyde (PGAL) or even as triose phosphate. Triose is a 3-carbon sugar (see carbohydrates). Most (5 out of 6 molecules) of the G3P produced is used to regenerate RuBP so the process can continue (see Calvin-Benson cycle). The 1 out of 6 molecules of the triose phosphates not "recycled" often condense to form