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Photosynthesis En
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromophores. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis En
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromophores. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanobacteria
Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blue-green algae, although they are not usually scientifically classified as algae. They appear to have originated in a freshwater or terrestrial environment. Sericytochromatia, the proposed name of the paraphyletic and most basal group, is the ancestor of both the non-photosynthetic group Melainabacteria and the photosynthetic cyanobacteria, also called Oxyphotobacteria. Cyanobacteria use photosynthetic pigments, such as carotenoids, phycobilins, and various forms of chlorophyll, which absorb energy from light. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes. These are flattened sacs called thylakoids where photosynthesis is performed. Phototrophic eukaryotes such as green plants perform photosynthesis in plast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calvin Cycle
The Calvin cycle, light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle of photosynthesis is a series of chemical reactions that convert carbon dioxide and hydrogen-carrier compounds into glucose. The Calvin cycle is present in all photosynthetic eukaryotes and also many photosynthetic bacteria. In plants, these reactions occur in the stroma, the fluid-filled region of a chloroplast outside the thylakoid membranes. These reactions take the products ( ATP and NADPH) of light-dependent reactions and perform further chemical processes on them. The Calvin cycle uses the chemical energy of ATP and reducing power of NADPH from the light dependent reactions to produce sugars for the plant to use. These substrates are used in a series of reduction-oxidation reactions to produce sugars in a step-wise process; there is no direct reaction that converts several molecules of to a sugar. There are three phases to the light-independ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. The human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinamide Adenine Dinucleotide Phosphate
Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a Cofactor (biochemistry), cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent ('hydrogen source'). It is used by all forms of cellular life. NADPH is the redox, reduced form of NADP. NADP differs from NAD+, NAD by the presence of an additional phosphate group on the 2' position of the ribose ring that carries the adenine Moiety (chemistry), moiety. This extra phosphate is added by NAD+ kinase, NAD+ kinase and removed by NADP+ phosphatase. Biosynthesis NADP In general, NADP+ is synthesized before NADPH is. Such a reaction usually starts with NAD+, NAD+ from either the de-novo or the salvage pathway, with NAD+ kinase, NAD+ kinase adding the extra phosphate group. ADP-ribosyl cyclase allows for synthesis from nicotinamide in the salvage pathway, and NADP+ phosphatase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organelle
In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as organs are to the body, hence ''organelle,'' the suffix ''-elle'' being a diminutive. Organelles are either separately enclosed within their own lipid bilayers (also called membrane-bound organelles) or are spatially distinct functional units without a surrounding lipid bilayer (non-membrane bound organelles). Although most organelles are functional units within cells, some function units that extend outside of cells are often termed organelles, such as cilia, the flagellum and archaellum, and the trichocyst. Organelles are identified by microscopy, and can also be purified by cell fractionation. There are many types of organelles, particularly in eukaryotic cells. They include structures that make up the endomembrane system (such as the nuclear envelope, endoplasmic reticulum, and G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to absorb energy from light. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. The presence of magnesium in chlorophyll was discovered in 1906, and was that element's first detection in living tissue. After initial work done by German chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Center
A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and pheophytin, as well as quinones. The energy of the photon is used to excite an electron of a pigment. The free energy created is then used, via a chain of nearby electron acceptors, for a transfer of hydrogen atoms (as protons and electrons) from H2O or hydrogen sulfide towards carbon dioxide, eventually producing glucose. These electron transfer steps ultimately result in the conversion of the energy of photons to chemical energy. Transforming light energy into c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
