Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.
Spherical phototrophic bacteria found in mud and stagnant water exposed to light.
Complexes containing CHLOROPHYLL and other photosensitive molecules. They serve to capture energy in the form of PHOTONS and are generally found as components of the PHOTOSYSTEM I PROTEIN COMPLEX or the PHOTOSYSTEM II PROTEIN COMPLEX.
Pyrrole containing pigments found in photosynthetic bacteria.
A genus of gram-negative, rod-shaped, phototrophic bacteria found in aquatic environments. Internal photosynthetic membranes are present as lamellae underlying the cytoplasmic membrane.
A large multisubunit protein complex found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to catalyze the splitting of WATER into DIOXYGEN and of reducing equivalents of HYDROGEN.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)
Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.
Chlorophylls from which the magnesium has been removed by treatment with weak acid.
A large multisubunit protein complex that is found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to drive electron transfer reactions that result in either the reduction of NADP to NADPH or the transport of PROTONS across the membrane.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.
Type C cytochromes that are small (12-14 kD) single-heme proteins. They function as mobile electron carriers between membrane-bound enzymes in photosynthetic BACTERIA.
A phylum of anoxygenic, phototrophic bacteria including the family Chlorobiaceae. They occur in aquatic sediments, sulfur springs, and hot springs and utilize reduced sulfur compounds instead of oxygen.
Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.
A widely cultivated plant, native to Asia, having succulent, edible leaves eaten as a vegetable. (From American Heritage Dictionary, 1982)
A genus of gram-negative bacteria widely distributed in fresh water as well as marine and hypersaline habitats.
Proteins found in any species of bacterium.
A phylum of bacteria consisting of the purple bacteria and their relatives which form a branch of the eubacterial tree. This group of predominantly gram-negative bacteria is classified based on homology of equivalent nucleotide sequences of 16S ribosomal RNA or by hybridization of ribosomal RNA or DNA with 16S and 23S ribosomal RNA.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A genus in the family ACETOBACTERACEAE consisting of chemoorganotrophic, straight rods with rounded ends. They are aerobic and acidophilic.
A family in the order Rhizobiales, class ALPHAPROTEOBACTERIA comprised of many genera of budding or appendaged bacteria.
Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.
Photochemistry is the study of chemical reactions induced by absorption of light, resulting in the promotion of electrons to higher energy levels and subsequent formation of radicals or excited molecules that can undergo various reaction pathways.
Organelles of phototrophic bacteria which contain photosynthetic pigments and which are formed from an invagination of the cytoplasmic membrane.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A genus of phototrophic, obligately anaerobic bacteria in the family Chlorobiaceae. They are found in hydrogen sulfide-containing mud and water environments.
A lipid-soluble benzoquinone which is involved in ELECTRON TRANSPORT in mitochondrial preparations. The compound occurs in the majority of aerobic organisms, from bacteria to higher plants and animals.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A genus of EUKARYOTES, in the phylum EUGLENIDA, found mostly in stagnant water. Characteristics include a pellicle usually marked by spiral or longitudinal striations.
The rate dynamics in chemical or physical systems.
Proteins, usually acting in oxidation-reduction reactions, containing iron but no porphyrin groups. (Lehninger, Principles of Biochemistry, 1993, pG-10)
A family of phototrophic bacteria, in the order Rhodospirillales, isolated from stagnant water and mud.
A pre-emergent herbicide.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A specific bacteriochlorophyll that is similar in structure to chlorophyll a.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
A family of phototrophic purple sulfur bacteria that deposit globules of elemental sulfur inside their cells. They are found in diverse aquatic environments.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Non-pathogenic ovoid to rod-shaped bacteria that are widely distributed and found in fresh water as well as marine and hypersaline habitats.
A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)
A genus of facultatively or obligately anaerobic marine phototrophic bacteria, in the family RHODOBACTERACEAE.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A genus of gram-negative, ovoid to rod-shaped bacteria that is phototrophic. All species use ammonia as a nitrogen source. Some strains are found only in sulfide-containing freshwater habitats exposed to light while others may occur in marine, estuarine, and freshwater environments.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.
The accumulation of an electric charge on a object
Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
Proteins that form the structure of the NUCLEAR PORE. They are involved in active, facilitated and passive transport of molecules in and out of the CELL NUCLEUS.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Dimethylamines are organic compounds that contain two methyl groups (-CH3) bonded to a nitrogen atom (N), with the general formula (CH3)2NH. They can act as secondary amines and are commonly used in chemical synthesis, but they are not typically found as natural components in the human body.
Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
The functional hereditary units of BACTERIA.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii. (1/2359)

Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.  (+info)

Two light-activated conductances in the eye of the green alga Volvox carteri. (2/2359)

Photoreceptor currents of the multicellular green alga Volvox carteri were analyzed using a dissolver mutant. The photocurrents are restricted to the eyespot region of somatic cells. Photocurrents are detectable from intact cells and excised eyes. The rhodopsin action spectrum suggests that the currents are induced by Volvox rhodopsin. Flash-induced photocurrents are a composition of a fast Ca2+-carried current (PF) and a slower current (PS), which is carried by H+. PF is a high-intensity response that appears with a delay of less than 50 micros after flash. The stimulus-response curve of its initial rise is fit by a single exponential and parallels the rhodopsin bleaching. These two observations suggest that the responsible channel is closely connected to the rhodopsin, both forming a tight complex. At low flash energies PS is dominating. The current delay increases up to 10 ms, and the PS amplitude saturates when only a few percent of the rhodopsin is bleached. The data are in favor of a second signaling system, which includes a signal transducer mediating between rhodopsin and the channel. We present a model of how different modes of signal transduction are accomplished in this alga under different light conditions.  (+info)

Multiple pathways for ultrafast transduction of light energy in the photosynthetic reaction center of Rhodobacter sphaeroides. (3/2359)

A pathway of electron transfer is described that operates in the wild-type reaction center (RC) of the photosynthetic bacterium Rhodobacter sphaeroides. The pathway does not involve the excited state of the special pair dimer of bacteriochlorophylls (P*), but instead is driven by the excited state of the monomeric bacteriochlorophyll (BA*) present in the active branch of pigments along which electron transfer occurs. Pump-probe experiments were performed at 77 K on membrane-bound RCs by using different excitation wavelengths, to investigate the formation of the charge separated state P+HA-. In experiments in which P or BA was selectively excited at 880 nm or 796 nm, respectively, the formation of P+HA- was associated with similar time constants of 1.5 ps and 1. 7 ps. However, the spectral changes associated with the two time constants are very different. Global analysis of the transient spectra shows that a mixture of P+BA- and P* is formed in parallel from BA* on a subpicosecond time scale. In contrast, excitation of the inactive branch monomeric bacteriochlorophyll (BB) and the high exciton component of P (P+) resulted in electron transfer only after relaxation to P*. The multiple pathways for primary electron transfer in the bacterial RC are discussed with regard to the mechanism of charge separation in the RC of photosystem II from higher plants.  (+info)

Lipophilicity determination of some potential photosystem II inhibitors on reversed-phase high-performance thin-layer chromatography. (4/2359)

The retention characteristics of 25 2-cyano-3-methylthio-3-substituted amine-acrylates are determined using reversed-phase thin-layer chromatography (RP-TLC) with methanol-water mixtures as eluents. The relationship between Rm values and partition coefficients (C log P) are established. The Rm values decrease linearly with increasing methanol concentration in the eluent. The Rm values extrapolated to zero organic modifier concentration (Rm0) in the eluent are highly related to C log P. The Rm0 value can be used to evaluate the lipophilicity of this kind of compound.  (+info)

A functional model for O-O bond formation by the O2-evolving complex in photosystem II. (5/2359)

The formation of molecular oxygen from water in photosynthesis is catalyzed by photosystem II at an active site containing four manganese ions that are arranged in di-mu-oxo dimanganese units (where mu is a bridging mode). The complex [H2O(terpy)Mn(O)2Mn(terpy)OH2](NO3)3 (terpy is 2,2':6', 2"-terpyridine), which was synthesized and structurally characterized, contains a di-mu-oxo manganese dimer and catalyzes the conversion of sodium hypochlorite to molecular oxygen. Oxygen-18 isotope labeling showed that water is the source of the oxygen atoms in the molecular oxygen evolved, and so this system is a functional model for photosynthetic water oxidation.  (+info)

Photosystem I, an improved model of the stromal subunits PsaC, PsaD, and PsaE. (6/2359)

An improved electron density map of photosystem I (PSI) calculated at 4-A resolution yields a more detailed structural model of the stromal subunits PsaC, PsaD, and PsaE than previously reported. The NMR structure of the subunit PsaE of PSI from Synechococcus sp. PCC7002 (Falzone, C. J., Kao, Y.-H., Zhao, J., Bryant, D. A., and Lecomte, J. T. J. (1994) Biochemistry 33, 6052-6062) has been used as a model to interpret the region of the electron density map corresponding to this subunit. The spatial orientation with respect to other subunits is described as well as the possible interactions between the stromal subunits. A first model of PsaD consisting of a four-stranded beta-sheet and an alpha-helix is suggested, indicating that this subunit partly shields PsaC from the stromal side. In addition to the improvements on the stromal subunits, the structural model of the membrane-integral region of PSI is also extended. The current electron density map allows the identification of the N and C termini of the subunits PsaA and PsaB. The 11-transmembrane alpha-helices of these subunits can now be assigned uniquely to the hydrophobic segments identified by hydrophobicity analyses.  (+info)

Localization of two phylloquinones, QK and QK', in an improved electron density map of photosystem I at 4-A resolution. (7/2359)

An improved electron density map of photosystem I from Synechococcus elongatus calculated at 4-A resolution for the first time reveals a second phylloquinone molecule and thereby completes the set of cofactors constituting the electron transfer system of this iron-sulfur type photosynthetic reaction center: six chlorophyll a, two phylloquinones, and three Fe4S4 clusters. The location of the newly identified phylloquinone pair, the individual plane orientations of these molecules, and the resulting distances to other cofactors of the electron transfer system are discussed and compared with those determined by magnetic resonance techniques.  (+info)

Structural features and assembly of the soluble overexpressed PsaD subunit of photosystem I. (8/2359)

PsaD is a peripheral protein on the reducing side of photosystem I (PS I). We expressed the psaD gene from the thermophilic cyanobacterium Mastigocladus laminosus in Escherichia coli and obtained a soluble protein with a polyhistidine tag at the carboxyl terminus. The soluble PsaD protein was purified by Ni-affinity chromatography and had a mass of 16716 Da by MALDI-TOF. The N-terminal amino acid sequence of the overexpressed PsaD matched the N-terminal sequence of the native PsaD from M. laminosus. The soluble PsaD could assemble into the PsaD-less PS I. As determined by isothermal titration calorimetry, PsaD bound to PS I with 1.0 binding site per PS I, the binding constant of 7.7x10(6) M-1, and the enthalpy change of -93.6 kJ mol-1. This is the first time that the binding constant and binding heat have been determined in the assembly of any photosynthetic membrane protein. To identify the surface-exposed domains, purified PS I complexes and overexpressed PsaD were treated with N-hydroxysuccinimidobiotin (NHS-biotin) and biotin-maleimide, and the biotinylated residues were mapped. The Cys66, Lys21, Arg118 and Arg119 residues were exposed on the surface of soluble PsaD whereas the Lys129 and Lys131 residues were not exposed on the surface. Consistent with the X-ray crystallographic studies on PS I, circular dichroism spectroscopy revealed that PsaD contains a small proportion of alpha-helical conformation.  (+info)

Photosynthetic Reaction Center (RC) Complex Proteins are specialized protein-pigment structures that play a crucial role in the primary process of light-driven electron transport during photosynthesis. They are present in the thylakoid membranes of cyanobacteria, algae, and higher plants.

The Photosynthetic Reaction Center Complex Proteins are composed of two major components: the light-harvesting complex (LHC) and the reaction center (RC). The LHC contains antenna pigments like chlorophylls and carotenoids that absorb sunlight and transfer the excitation energy to the RC. The RC is a multi-subunit protein complex containing cofactors such as bacteriochlorophyll, pheophytin, quinones, and iron-sulfur clusters.

When a photon of light is absorbed by the antenna pigments in the LHC, the energy is transferred to the RC, where it initiates a charge separation event. This results in the transfer of an electron from a donor molecule to an acceptor molecule, creating a flow of electrical charge and generating a transmembrane electrochemical gradient. The energy stored in this gradient is then used to synthesize ATP and reduce NADP+, which are essential for carbon fixation and other metabolic processes in the cell.

In summary, Photosynthetic Reaction Center Complex Proteins are specialized protein structures involved in capturing light energy and converting it into chemical energy during photosynthesis, ultimately driving the synthesis of ATP and NADPH for use in carbon fixation and other metabolic processes.

Rhodobacter sphaeroides is not a medical term, but rather a scientific name for a type of bacteria. It belongs to the class of proteobacteria and is commonly found in soil, fresh water, and the ocean. This bacterium is capable of photosynthesis, and it can use light as an energy source, converting it into chemical energy. Rhodobacter sphaeroides is often studied in research settings due to its unique metabolic capabilities and potential applications in biotechnology.

In a medical context, Rhodobacter sphaeroides may be mentioned in relation to rare cases of infection, particularly in individuals with weakened immune systems. However, it is not considered a significant human pathogen, and there are no specific medical definitions associated with this bacterium.

Light-harvesting protein complexes are specialized structures in photosynthetic organisms, such as plants, algae, and some bacteria, that capture and transfer light energy to the reaction centers where the initial chemical reactions of photosynthesis occur. These complexes consist of proteins and pigments (primarily chlorophylls and carotenoids) arranged in a way that allows them to absorb light most efficiently. The absorbed light energy is then converted into electrical charges, which are transferred to the reaction centers for further chemical reactions leading to the production of organic compounds and oxygen. The light-harvesting protein complexes play a crucial role in initiating the process of photosynthesis and optimizing its efficiency by capturing and distributing light energy.

Bacteriochlorophylls are a type of pigment that are found in certain bacteria and are used in photosynthesis. They are similar to chlorophylls, which are found in plants and algae, but have some differences in their structure and absorption spectrum. Bacteriochlorophylls absorb light at longer wavelengths than chlorophylls, with absorption peaks in the near-infrared region of the electromagnetic spectrum. This allows bacteria that contain bacteriochlorophylls to carry out photosynthesis in environments with low levels of light or at great depths in the ocean where sunlight is scarce.

There are several different types of bacteriochlorophylls, including bacteriochlorophyll a, bacteriochlorophyll b, and bacteriochlorophyll c. These pigments play a role in the capture of light energy during photosynthesis and are involved in the electron transfer processes that occur during this process. Bacteriochlorophylls are also used as a taxonomic marker to help classify certain groups of bacteria.

Rhodopseudomonas is a genus of gram-negative, rod-shaped bacteria that are capable of photosynthesis. These bacteria contain bacteriochlorophyll and can use light as an energy source in the absence of oxygen, which makes them facultative anaerobes. They typically inhabit freshwater and soil environments, and some species are able to fix nitrogen gas. Rhodopseudomonas species are known to cause various infections in humans, including bacteremia, endocarditis, and respiratory tract infections, particularly in immunocompromised individuals. However, such infections are relatively rare.

Photosystem II Protein Complex is a crucial component of the photosynthetic apparatus in plants, algae, and cyanobacteria. It is a multi-subunit protein complex located in the thylakoid membrane of the chloroplasts. Photosystem II plays a vital role in light-dependent reactions of photosynthesis, where it absorbs sunlight and uses its energy to drive the oxidation of water molecules into oxygen, electrons, and protons.

The protein complex consists of several subunits, including the D1 and D2 proteins, which form the reaction center, and several antenna proteins that capture light energy and transfer it to the reaction center. Photosystem II also contains various cofactors, such as pigments (chlorophylls and carotenoids), redox-active metal ions (manganese and calcium), and quinones, which facilitate the charge separation and electron transfer processes during photosynthesis.

Photosystem II Protein Complex is responsible for the initial charge separation event in photosynthesis, which sets off a series of redox reactions that ultimately lead to the reduction of NADP+ to NADPH and the synthesis of ATP, providing energy for the carbon fixation reactions in the Calvin cycle. Additionally, Photosystem II Protein Complex is involved in oxygen evolution, contributing to the Earth's atmosphere's oxygen levels and making it an essential component of global carbon fixation and oxygen production.

The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.

The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.

The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.

Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.

Photosynthesis is not strictly a medical term, but it is a fundamental biological process with significant implications for medicine, particularly in understanding energy production in cells and the role of oxygen in sustaining life. Here's a general biological definition:

Photosynthesis is a process by which plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy in the form of organic compounds, such as glucose (or sugar), using water and carbon dioxide. This process primarily takes place in the chloroplasts of plant cells, specifically in structures called thylakoids. The overall reaction can be summarized as:

6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

In this equation, carbon dioxide (CO2) and water (H2O) are the reactants, while glucose (C6H12O6) and oxygen (O2) are the products. Photosynthesis has two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions occur in the thylakoid membrane and involve the conversion of light energy into ATP and NADPH, which are used to power the Calvin cycle. The Calvin cycle takes place in the stroma of chloroplasts and involves the synthesis of glucose from CO2 and water using the ATP and NADPH generated during the light-dependent reactions.

Understanding photosynthesis is crucial for understanding various biological processes, including cellular respiration, plant metabolism, and the global carbon cycle. Additionally, research into artificial photosynthesis has potential applications in renewable energy production and environmental remediation.

Chlorophyll is a green pigment found in the chloroplasts of photosynthetic plants, algae, and some bacteria. It plays an essential role in light-dependent reactions of photosynthesis by absorbing light energy, primarily from the blue and red parts of the electromagnetic spectrum, and converting it into chemical energy to fuel the synthesis of carbohydrates from carbon dioxide and water. The structure of chlorophyll includes a porphyrin ring, which binds a central magnesium ion, and a long phytol tail. There are several types of chlorophyll, including chlorophyll a and chlorophyll b, which have distinct absorption spectra and slightly different structures. Chlorophyll is crucial for the process of photosynthesis, enabling the conversion of sunlight into chemical energy and the release of oxygen as a byproduct.

Pheophytins are pigments that are formed when the magnesium ion is lost from chlorophylls, which are the green pigments involved in photosynthesis. This results in the conversion of chlorophyll a and chlorophyll b to pheophytin a and pheophytin b, respectively. Pheophytins do not participate in light absorption during photosynthesis and have a different spectral absorption pattern compared to chlorophylls. They are believed to play a role in the photoprotection of photosystem II by dissipating excess energy absorbed by the antenna complexes as heat, thereby preventing the formation of harmful reactive oxygen species.

Photosystem I Protein Complex, also known as PsaA/B-Protein or Photosystem I reaction center, is a large protein complex found in the thylakoid membrane of plant chloroplasts and cyanobacteria. It plays a crucial role in light-dependent reactions of photosynthesis, where it absorbs light energy and converts it into chemical energy in the form of NADPH.

The complex is composed of several subunits, including PsaA and PsaB, which are the core components that bind to chlorophyll a and bacteriochlorophyll a pigments. These pigments absorb light energy and transfer it to the reaction center, where it is used to drive the electron transport chain and generate a proton gradient across the membrane. This gradient is then used to produce ATP, which provides energy for the carbon fixation reactions in photosynthesis.

Photosystem I Protein Complex is also involved in cyclic electron flow, where electrons are recycled within the complex to generate additional ATP without producing NADPH. This process helps regulate the balance between ATP and NADPH production in the chloroplast and optimizes the efficiency of photosynthesis.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

Cyanobacteria, also known as blue-green algae, are a type of bacteria that obtain their energy through photosynthesis, similar to plants. They can produce oxygen and contain chlorophyll a, which gives them a greenish color. Some species of cyanobacteria can produce toxins that can be harmful to humans and animals if ingested or inhaled. They are found in various aquatic environments such as freshwater lakes, ponds, and oceans, as well as in damp soil and on rocks. Cyanobacteria are important contributors to the Earth's oxygen-rich atmosphere and play a significant role in the global carbon cycle.

Cytochrome c2 is a type of cytochrome, which is a small water-soluble protein involved in electron transport chains and associated with the inner membrane of mitochondria. Cytochrome c2 specifically contains heme as a cofactor and plays a role in the respiratory chain of certain bacteria, contributing to their energy production through oxidative phosphorylation. It is not found in human or mammalian cells.

Chlorobi, also known as green sulfur bacteria, are a group of anaerobic, phototrophic bacteria that contain chlorophylls a and b, as well as bacteriochlorophyll c, d, or e. They obtain energy through photosynthesis, using light as an energy source and sulfide or other reduced sulfur compounds as electron donors. These bacteria are typically found in environments with limited sunlight and high sulfide concentrations, such as in sediments of stratified water bodies or in microbial mats. They play a significant role in the global carbon and sulfur cycles.

Quinones are a class of organic compounds that contain a fully conjugated diketone structure. This structure consists of two carbonyl groups (C=O) separated by a double bond (C=C). Quinones can be found in various biological systems and synthetic compounds. They play important roles in many biochemical processes, such as electron transport chains and redox reactions. Some quinones are also known for their antimicrobial and anticancer properties. However, some quinones can be toxic or mutagenic at high concentrations.

Spectrophotometry is a technical analytical method used in the field of medicine and science to measure the amount of light absorbed or transmitted by a substance at specific wavelengths. This technique involves the use of a spectrophotometer, an instrument that measures the intensity of light as it passes through a sample.

In medical applications, spectrophotometry is often used in laboratory settings to analyze various biological samples such as blood, urine, and tissues. For example, it can be used to measure the concentration of specific chemicals or compounds in a sample by measuring the amount of light that is absorbed or transmitted at specific wavelengths.

In addition, spectrophotometry can also be used to assess the properties of biological tissues, such as their optical density and thickness. This information can be useful in the diagnosis and treatment of various medical conditions, including skin disorders, eye diseases, and cancer.

Overall, spectrophotometry is a valuable tool for medical professionals and researchers seeking to understand the composition and properties of various biological samples and tissues.

"Energy transfer" is a general term used in the field of physics and physiology, including medical sciences, to describe the process by which energy is passed from one system, entity, or location to another. In the context of medicine, energy transfer often refers to the ways in which cells and organ systems exchange and utilize various forms of energy for proper functioning and maintenance of life.

In a more specific sense, "energy transfer" may refer to:

1. Bioenergetics: This is the study of energy flow through living organisms, including the conversion, storage, and utilization of energy in biological systems. Key processes include cellular respiration, photosynthesis, and metabolic pathways that transform energy into forms useful for growth, maintenance, and reproduction.
2. Electron transfer: In biochemistry, electrons are transferred between molecules during redox reactions, which play a crucial role in energy production and consumption within cells. Examples include the electron transport chain (ETC) in mitochondria, where high-energy electrons from NADH and FADH2 are passed along a series of protein complexes to generate an electrochemical gradient that drives ATP synthesis.
3. Heat transfer: This is the exchange of thermal energy between systems or objects due to temperature differences. In medicine, heat transfer can be relevant in understanding how body temperature is regulated and maintained, as well as in therapeutic interventions such as hyperthermia or cryotherapy.
4. Mechanical energy transfer: This refers to the transmission of mechanical force or motion from one part of the body to another. For instance, muscle contractions generate forces that are transmitted through tendons and bones to produce movement and maintain posture.
5. Radiation therapy: In oncology, ionizing radiation is used to treat cancer by transferring energy to malignant cells, causing damage to their DNA and leading to cell death or impaired function.
6. Magnetic resonance imaging (MRI): This non-invasive diagnostic technique uses magnetic fields and radio waves to excite hydrogen nuclei in the body, which then release energy as they return to their ground state. The resulting signals are used to generate detailed images of internal structures and tissues.

In summary, "energy transfer" is a broad term that encompasses various processes by which different forms of energy (thermal, mechanical, electromagnetic, etc.) are exchanged or transmitted between systems or objects in the context of medicine and healthcare.

"Spinacia oleracea" is the scientific name for a plant species, not a medical term. It is commonly known as spinach, a leafy green vegetable. While spinach has many health benefits and is often recommended as part of a balanced diet, it does not have a specific medical definition.

Spinach is rich in various nutrients such as iron, calcium, vitamin A, vitamin C, and folic acid. It can contribute to overall health, support immune function, and provide antioxidant benefits. However, it is important to note that 'Spinacia oleracea' itself does not have a medical definition.

Rhodobacter is not a medical term, but a genus of bacteria found in the environment. It is commonly found in aquatic environments and can perform photosynthesis, although it is not classified as a plant. Some species of Rhodobacter are capable of fixing nitrogen gas from the atmosphere, making them important contributors to the global nitrogen cycle.

While there may be some medical research into the potential uses or impacts of certain species of Rhodobacter, there is no widely recognized medical definition for this term. If you have any specific concerns about bacteria or infections, it's best to consult with a healthcare professional for accurate information and advice.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Proteobacteria is a major class of Gram-negative bacteria that includes a wide variety of pathogens and free-living organisms. This class is divided into six subclasses: Alpha, Beta, Gamma, Delta, Epsilon, and Zeta proteobacteria. Proteobacteria are characterized by their single circular chromosome and the presence of lipopolysaccharide (LPS) in their outer membrane. They can be found in a wide range of environments, including soil, water, and the gastrointestinal tracts of animals. Some notable examples of Proteobacteria include Escherichia coli, Salmonella enterica, and Yersinia pestis.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

'Acidiphilium' is a genus of bacteria that are characterized by their ability to thrive in highly acidic environments, typically with a pH between 1 and 5. These bacteria are gram-negative, motile, and rod-shaped, and they are commonly found in natural environments such as acid mine drainage, soil, and water. They are able to use a variety of organic compounds as their energy source and are often involved in the biogeochemical cycling of elements such as carbon, nitrogen, and sulfur. Some species of 'Acidiphilium' have been studied for their potential applications in bioremediation and other industrial processes.

Hyphomicrobiaceae is a family of bacteria that are characterized by their unique mode of reproduction known as "budding." This type of reproduction involves the formation of a new cell, or bud, on the surface of the parent cell. Once the bud has reached a certain size, it will separate from the parent cell and become a fully functioning independent organism.

Members of Hyphomicrobiaceae are typically gram-negative, aerobic bacteria that are found in a variety of environments, including soil, water, and plant material. They are often associated with nitrogen fixation, a process by which certain bacteria are able to convert atmospheric nitrogen into ammonia, a form that can be used by plants for growth.

One notable genus within Hyphomicrobiaceae is Hyphomicrobium, which is known for its ability to oxidize methanol and other single-carbon compounds as a source of energy. This makes it an important player in the global carbon cycle, as it helps to convert methane, a potent greenhouse gas, into less harmful forms.

Overall, Hyphomicrobiaceae is an interesting family of bacteria with diverse metabolic capabilities and ecological roles.

An electron is a subatomic particle, symbol e-, with a negative electric charge. Electrons are fundamental components of atoms and are responsible for the chemical bonding between atoms to form molecules. They are located in an atom's electron cloud, which is the outermost region of an atom and contains negatively charged electrons that surround the positively charged nucleus.

Electrons have a mass that is much smaller than that of protons or neutrons, making them virtually weightless on the atomic scale. They are also known to exhibit both particle-like and wave-like properties, which is a fundamental concept in quantum mechanics. Electrons play a crucial role in various physical phenomena, such as electricity, magnetism, and chemical reactions.

I'm sorry for any confusion, but "photochemistry" is not a term typically used in medical definitions. Photochemistry is a branch of chemistry that deals with the chemical effects of light. It involves the absorption of light by a substance, which can lead to the promotion of an electron to a higher energy state, and subsequently result in various chemical reactions.

In a medical context, photochemical processes might be discussed in relation to certain therapies or diagnostic techniques, such as photodynamic therapy for cancer treatment, where a photosensitizing agent is used that reacts with light to produce singlet oxygen or other reactive species to destroy nearby cells. However, it's not a term used to define a specific medical condition or concept in the same way that one might define "inflammation" or "metabolism."

Bacterial chromatophores are membranous structures within certain bacteria that contain pigments and are involved in light absorption. They are primarily found in photosynthetic bacteria, where they play a crucial role in the process of photosynthesis by capturing light energy and converting it into chemical energy.

The term "chromatophore" is derived from the Greek words "chroma," meaning color, and "phoros," meaning bearer. In bacteria, chromatophores are typically composed of one or more membrane-bound vesicles called thylakoids, which contain various pigments such as bacteriochlorophylls and carotenoids.

Bacterial chromatophores can be found in several groups of photosynthetic bacteria, including cyanobacteria, green sulfur bacteria, purple sulfur bacteria, and purple nonsulfur bacteria. The specific arrangement and composition of the pigments within the chromatophores determine the type of light that is absorbed and the wavelengths that are utilized for photosynthesis.

Overall, bacterial chromatophores are essential organelles for the survival and growth of many photosynthetic bacteria, allowing them to harness the energy from sunlight to fuel their metabolic processes.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Chlorobium is a genus of photosynthetic bacteria that are primarily found in anaerobic environments, such as freshwater and marine sediments, and in the upper layers of microbial mats. These bacteria contain bacteriochlorophylls and use light energy to convert carbon dioxide into organic compounds through a process called chemosynthesis. Chlorobium species are important contributors to the global carbon cycle and play a significant role in the ecology of anaerobic environments.

The medical relevance of Chlorobium is limited, as these bacteria do not typically interact with humans or animals in a way that causes disease. However, they may be of interest to researchers studying photosynthesis, carbon cycling, and microbial ecology.

Ubiquinone, also known as coenzyme Q10 (CoQ10), is a lipid-soluble benzoquinone that plays a crucial role in the mitochondrial electron transport chain as an essential component of Complexes I, II, and III. It functions as an electron carrier, assisting in the transfer of electrons from reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2) to molecular oxygen during oxidative phosphorylation, thereby contributing to the generation of adenosine triphosphate (ATP), the primary energy currency of the cell.

Additionally, ubiquinone acts as a potent antioxidant in both membranes and lipoproteins, protecting against lipid peroxidation and oxidative damage to proteins and DNA. Its antioxidant properties stem from its ability to donate electrons and regenerate other antioxidants like vitamin E. Ubiquinone is synthesized endogenously in all human cells, with the highest concentrations found in tissues with high energy demands, such as the heart, liver, kidneys, and skeletal muscles.

Deficiency in ubiquinone can result from genetic disorders, aging, or certain medications (such as statins), leading to impaired mitochondrial function and increased oxidative stress. Supplementation with ubiquinone has been explored as a potential therapeutic strategy for various conditions associated with mitochondrial dysfunction and oxidative stress, including cardiovascular diseases, neurodegenerative disorders, and cancer.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

'Euglena' is a genus of unicellular flagellate protists that are typically characterized by their oval-shaped bodies, long whip-like tail (flagellum), and eyespot (stigma) which helps them to move towards light. They are commonly found in freshwater environments and can also be found in soil and brackish water. Some species of Euglena have the ability to photosynthesize, while others obtain their nutrition through heterotrophy (consuming other organisms or organic matter). The term 'Euglena' is derived from the Greek word 'euglenes', which means "well-shaped" or "true-eyed". Medical professionals and researchers may study Euglena as part of broader research into protists, microbiology, or ecology.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Non-heme iron proteins are a type of iron-containing protein that do not contain heme as their prosthetic group. Heme is a complex molecule consisting of an iron atom contained in the center of a porphyrin ring, which is a large organic molecule made up of four pyrrole rings joined together. In contrast, non-heme iron proteins contain iron that is bound to the protein in other ways, such as through coordination with amino acid side chains or through association with an iron-sulfur cluster.

Examples of non-heme iron proteins include ferritin and transferrin, which are involved in the storage and transport of iron in the body, respectively. Ferritin is a protein that stores iron in a form that is safe and bioavailable for use by the body. Transferrin, on the other hand, binds to iron in the intestines and transports it to cells throughout the body.

Non-heme iron proteins are important for many biological processes, including oxygen transport, electron transfer, and enzyme catalysis. They play a crucial role in energy metabolism, DNA synthesis, and other essential functions.

Rhodospirillaceae is a family of purple bacteria within the class Alphaproteobacteria. These bacteria are characterized by their ability to perform anoxygenic photosynthesis, using bacteriochlorophyll and other pigments to capture light energy for use in metabolism. They typically contain one or more polar flagella and have a spiral or curved cell shape. Members of this family can be found in various environments such as freshwater, marine habitats, and soil, where they play important roles in carbon and nitrogen cycling. Some species are capable of fixing atmospheric nitrogen, making them significant contributors to the global nitrogen cycle.

Diuron is a pesticide and herbicide that is used to control weeds in various settings, such as agriculture, landscaping, and forestry. Its chemical name is 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Diuron works by inhibiting photosynthesis in plants, which prevents them from growing and eventually kills them.

While diuron is effective at controlling weeds, it can also have harmful effects on non-target organisms, including aquatic life and pollinators. Additionally, there are concerns about the potential for diuron to contaminate water sources and pose risks to human health. As a result, its use is regulated in many countries, and there are restrictions on how it can be applied and disposed of.

It's worth noting that Diuron is not a medical term or a drug used for treating any medical condition in humans or animals.

I'm sorry for any confusion, but "spectrum analysis" is not a commonly used medical term. Spectrum analysis is a term that is more frequently used in the fields of physics, mathematics, and engineering to describe the process of breaking down a signal or a wave into its different frequencies and amplitudes, creating a visual representation called a spectrum.

If you have any concerns about a medical issue, I would recommend consulting with a healthcare professional for accurate information and guidance.

Bacteriochlorophyll A is a type of pigment-protein complex found in certain photosynthetic bacteria. It plays a crucial role in the process of anaerobic photosynthesis, where it absorbs light energy and converts it into chemical energy through a series of reactions.

The structure of bacteriochlorophyll A is similar to that of chlorophylls found in plants and cyanobacteria, but with some key differences. One major difference is the type of light that it absorbs. While chlorophylls absorb light primarily in the blue and red regions of the electromagnetic spectrum, bacteriochlorophyll A absorbs light in the near-infrared region, between 700 and 1000 nanometers.

Bacteriochlorophyll A is an essential component of the photosynthetic apparatus in purple bacteria and green sulfur bacteria, which are two groups of photosynthetic bacteria that live in environments with low light levels. These bacteria use bacteriochlorophyll A to capture light energy and power the synthesis of ATP and NADPH, which are used to fuel the production of organic compounds from carbon dioxide.

In summary, bacteriochlorophyll A is a type of pigment-protein complex found in certain photosynthetic bacteria that plays a crucial role in anaerobic photosynthesis by absorbing light energy and converting it into chemical energy through a series of reactions.

In the context of medicine, particularly in relation to cancer treatment, protons refer to positively charged subatomic particles found in the nucleus of an atom. Proton therapy, a type of radiation therapy, uses a beam of protons to target and destroy cancer cells with high precision, minimizing damage to surrounding healthy tissue. The concentrated dose of radiation is delivered directly to the tumor site, reducing side effects and improving quality of life during treatment.

Chromatiaceae is a family of bacteria that are primarily characterized by their ability to photosynthesize and store energy in the form of sulfur granules. These bacteria are often found in aquatic environments, such as in salt marshes, freshwater sediments, and marine ecosystems. They are capable of using reduced sulfur compounds as an electron donor during photosynthesis, which distinguishes them from other photosynthetic bacteria that use water as an electron donor.

Chromatiaceae bacteria are gram-negative rods or curved rods, and they typically form distinct layers in the environment where they live. They are often found in stratified water columns, where they can form a layer of purple or brown-colored cells that are visible to the naked eye. The pigmentation comes from bacteriochlorophylls and carotenoids, which are used in light absorption during photosynthesis.

These bacteria play an important role in the biogeochemical cycling of sulfur and carbon in aquatic environments. They can help to remove excess nutrients from the water column, and they can also serve as a food source for other organisms in the ecosystem. However, some species of Chromatiaceae can also be associated with harmful algal blooms or other environmental disturbances that can have negative impacts on water quality and aquatic life.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Rhodobacter capsulatus is not a medical term, but a species name in the field of microbiology. It refers to a type of purple nonsulfur bacteria that is capable of photosynthesis and can be found in freshwater and soil environments. These bacteria are known for their ability to switch between using light and organic compounds as sources of energy, depending on the availability of each. They have been studied for their potential applications in biotechnology and renewable energy production.

While not directly related to medical definitions, some research has explored the potential use of Rhodobacter capsulatus in bioremediation and wastewater treatment due to its ability to break down various organic compounds. However, it is not a pathogenic organism and does not have any direct relevance to human health or disease.

Cytochrome c is a small protein that is involved in the electron transport chain, a key part of cellular respiration in which cells generate energy in the form of ATP. Cytochrome c contains a heme group, which binds to and transports electrons. The cytochrome c group refers to a class of related cytochromes that have similar structures and functions. These proteins are found in the mitochondria of eukaryotic cells (such as those of plants and animals) and in the inner membranes of bacteria. They play a crucial role in the production of energy within the cell, and are also involved in certain types of programmed cell death (apoptosis).

I apologize for any confusion, but "Rhodovulum" is not a medical term, but rather a taxonomic genus name in the field of microbiology. It belongs to the family of purple sulfur bacteria, Rhodospirillaceae, and includes several species of photosynthetic, gram-negative bacteria that are commonly found in aquatic environments. These bacteria are capable of using light as an energy source and sulfur compounds as electron donors during photosynthesis. They play a role in the biogeochemical cycling of elements such as carbon, sulfur, and nitrogen in various ecosystems.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Electrochemistry is a branch of chemistry that deals with the interconversion of electrical energy and chemical energy. It involves the study of chemical processes that cause electrons to move, resulting in the transfer of electrical charge, and the reverse processes by which electrical energy can be used to drive chemical reactions. This field encompasses various phenomena such as the generation of electricity from chemical sources (as in batteries), the electrolysis of substances, and corrosion. Electrochemical reactions are fundamental to many technologies, including energy storage and conversion, environmental protection, and medical diagnostics.

"Chromatium" is a genus of bacteria that are commonly found in aquatic environments, particularly in anaerobic or low-oxygen conditions. These bacteria are known for their ability to perform anaerobic respiration using sulfur as the final electron acceptor in the electron transport chain. This process is often referred to as "sulfur reduction" or "sulfur respiration."

The name "Chromatium" comes from the Greek word "chroma," which means "color," and refers to the distinctive purple color of these bacteria, which is due to the presence of bacteriochlorophyll and carotenoid pigments. These pigments allow Chromatium species to perform photosynthesis, using light energy to convert carbon dioxide into organic compounds.

It's worth noting that "Chromatium" is a specific taxonomic name for a genus of bacteria, and should not be confused with the more general term "chromatin," which refers to the complex of DNA, histone proteins, and other molecules that make up the chromosomes in eukaryotic cells.

I'm sorry for any confusion, but "thermodynamics" is not a term that has a specific medical definition. It is a branch of physics that deals with the relationships between heat and other forms of energy. However, the principles of thermodynamics can be applied to biological systems, including those in the human body, such as in the study of metabolism or muscle function. But in a medical context, "thermodynamics" would not be a term used independently as a diagnosis, treatment, or any medical condition.

Electron Spin Resonance (ESR) Spectroscopy, also known as Electron Paramagnetic Resonance (EPR) Spectroscopy, is a technique used to investigate materials with unpaired electrons. It is based on the principle of absorption of energy by the unpaired electrons when they are exposed to an external magnetic field and microwave radiation.

In this technique, a sample is placed in a magnetic field and microwave radiation is applied. The unpaired electrons in the sample absorb energy and change their spin state when the energy of the microwaves matches the energy difference between the spin states. This absorption of energy is recorded as a function of the magnetic field strength, producing an ESR spectrum.

ESR spectroscopy can provide information about the number, type, and behavior of unpaired electrons in a sample, as well as the local environment around the electron. It is widely used in physics, chemistry, and biology to study materials such as free radicals, transition metal ions, and defects in solids.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.

For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.

It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.

Iron-sulfur proteins are a group of metalloproteins that contain iron and sulfur atoms in their active centers. These clusters of iron and sulfur atoms, also known as iron-sulfur clusters, can exist in various forms, including Fe-S, 2Fe-2S, 3Fe-4S, and 4Fe-4S structures. The iron atoms are coordinated to the protein through cysteine residues, while the sulfur atoms can be in the form of sulfide (S2-) or sulfane (-S-).

These proteins play crucial roles in many biological processes, such as electron transfer, redox reactions, and enzyme catalysis. They are found in various organisms, from bacteria to humans, and are involved in a wide range of cellular functions, including energy metabolism, photosynthesis, nitrogen fixation, and DNA repair.

Iron-sulfur proteins can be classified into several categories based on their structure and function, such as ferredoxins, Rieske proteins, high-potential iron-sulfur proteins (HiPIPs), and radical SAM enzymes. Dysregulation or mutations in iron-sulfur protein genes have been linked to various human diseases, including neurodegenerative disorders, cancer, and mitochondrial disorders.

Cytochromes are a type of hemeprotein found in the mitochondria and other cellular membranes of organisms. They contain a heme group, which is a prosthetic group composed of an iron atom surrounded by a porphyrin ring. This structure allows cytochromes to participate in redox reactions, acting as electron carriers in various biological processes.

There are several types of cytochromes, classified based on the type of heme they contain and their absorption spectra. Some of the most well-known cytochromes include:

* Cytochrome c: a small, mobile protein found in the inner mitochondrial membrane that plays a crucial role in the electron transport chain during cellular respiration.
* Cytochrome P450: a large family of enzymes involved in the metabolism of drugs, toxins, and other xenobiotics. They are found in various tissues, including the liver, lungs, and skin.
* Cytochrome b: a component of several electron transport chains, including those found in mitochondria, bacteria, and chloroplasts.

Cytochromes play essential roles in energy production, detoxification, and other metabolic processes, making them vital for the survival and function of living organisms.

I'm sorry for any confusion, but static electricity is not a term that has a specific medical definition. Static electricity is an electrical charge that builds up on the surface of objects. This occurs when there is an imbalance of electric charges within or on the surface of a material. It can be caused by certain conditions, such as friction, which can build up an electric charge.

While not a medical term, static electricity can have various effects in different settings, including medical ones. For instance, it can cause issues with electronic equipment used in healthcare settings. Additionally, some people may experience a shock or spark when they touch a conductive object that has been charged with static electricity. However, these occurrences are not typically considered medical conditions or issues.

Benzoquinones are a type of chemical compound that contain a benzene ring (a cyclic arrangement of six carbon atoms) with two ketone functional groups (-C=O) in the 1,4-positions. They exist in two stable forms, namely ortho-benzoquinone and para-benzoquinone, depending on the orientation of the ketone groups relative to each other.

Benzoquinones are important intermediates in various biological processes and are also used in industrial applications such as dyes, pigments, and pharmaceuticals. They can be produced synthetically or obtained naturally from certain plants and microorganisms.

In the medical field, benzoquinones have been studied for their potential therapeutic effects, particularly in the treatment of cancer and infectious diseases. However, they are also known to exhibit toxicity and may cause adverse reactions in some individuals. Therefore, further research is needed to fully understand their mechanisms of action and potential risks before they can be safely used as drugs or therapies.

Nuclear pore complex proteins, also known as nucleoporins, are a group of specialized proteins that make up the nuclear pore complex (NPC), a large protein structure found in the nuclear envelope of eukaryotic cells. The NPC regulates the transport of molecules between the nucleus and the cytoplasm.

Nucleoporins are organized into distinct subcomplexes, which together form the NPC. They contain phenylalanine-glycine (FG) repeats, which are stretches of amino acids rich in phenylalanine and glycine residues. These FG repeats interact with transport factors, which are responsible for carrying molecules through the NPC.

Nucleoporins play a critical role in the regulation of nuclear transport, and mutations in these proteins have been linked to various human diseases, including neurological disorders and cancer.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

Hydrogen bonding is not a medical term per se, but it is a fundamental concept in chemistry and biology that is relevant to the field of medicine. Here's a general definition:

Hydrogen bonding is a type of attractive force between molecules or within a molecule, which occurs when a hydrogen atom is bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is then attracted to another electronegative atom. This attraction results in the formation of a partially covalent bond known as a "hydrogen bond."

In biological systems, hydrogen bonding plays a crucial role in the structure and function of many biomolecules, such as DNA, proteins, and carbohydrates. For example, the double helix structure of DNA is stabilized by hydrogen bonds between complementary base pairs (adenine-thymine and guanine-cytosine). Similarly, the three-dimensional structure of proteins is maintained by a network of hydrogen bonds that help to determine their function.

In medical contexts, hydrogen bonding can be relevant in understanding drug-receptor interactions, where hydrogen bonds between a drug molecule and its target protein can enhance the binding affinity and specificity of the interaction, leading to more effective therapeutic outcomes.

Heme is not a medical term per se, but it is a term used in the field of medicine and biology. Heme is a prosthetic group found in hemoproteins, which are proteins that contain a heme iron complex. This complex plays a crucial role in various biological processes, including oxygen transport (in hemoglobin), electron transfer (in cytochromes), and chemical catalysis (in peroxidases and catalases).

The heme group consists of an organic component called a porphyrin ring, which binds to a central iron atom. The iron atom can bind or release electrons, making it essential for redox reactions in the body. Heme is also vital for the formation of hemoglobin and myoglobin, proteins responsible for oxygen transport and storage in the blood and muscles, respectively.

In summary, heme is a complex organic-inorganic structure that plays a critical role in several biological processes, particularly in electron transfer and oxygen transport.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Bacteria are single-celled microorganisms that are among the earliest known life forms on Earth. They are typically characterized as having a cell wall and no membrane-bound organelles. The majority of bacteria have a prokaryotic organization, meaning they lack a nucleus and other membrane-bound organelles.

Bacteria exist in diverse environments and can be found in every habitat on Earth, including soil, water, and the bodies of plants and animals. Some bacteria are beneficial to their hosts, while others can cause disease. Beneficial bacteria play important roles in processes such as digestion, nitrogen fixation, and biogeochemical cycling.

Bacteria reproduce asexually through binary fission or budding, and some species can also exchange genetic material through conjugation. They have a wide range of metabolic capabilities, with many using organic compounds as their source of energy, while others are capable of photosynthesis or chemosynthesis.

Bacteria are highly adaptable and can evolve rapidly in response to environmental changes. This has led to the development of antibiotic resistance in some species, which poses a significant public health challenge. Understanding the biology and behavior of bacteria is essential for developing strategies to prevent and treat bacterial infections and diseases.

Site-directed mutagenesis is a molecular biology technique used to introduce specific and targeted changes to a specific DNA sequence. This process involves creating a new variant of a gene or a specific region of interest within a DNA molecule by introducing a planned, deliberate change, or mutation, at a predetermined site within the DNA sequence.

The methodology typically involves the use of molecular tools such as PCR (polymerase chain reaction), restriction enzymes, and/or ligases to introduce the desired mutation(s) into a plasmid or other vector containing the target DNA sequence. The resulting modified DNA molecule can then be used to transform host cells, allowing for the production of large quantities of the mutated gene or protein for further study.

Site-directed mutagenesis is a valuable tool in basic research, drug discovery, and biotechnology applications where specific changes to a DNA sequence are required to understand gene function, investigate protein structure/function relationships, or engineer novel biological properties into existing genes or proteins.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

Dimethylamine is an organic compound with the formula (CH3)2NH. It is a colorless gas that is highly soluble in water and polar solvents. Dimethylamine is a derivative of ammonia (NH3) in which two hydrogen atoms are replaced by methyl groups (CH3).

Dimethylamines, in medical terminology, typically refer to compounds that contain the functional group -N(CH3)2. These compounds can have various biological activities and may be used as drugs or therapeutic agents. For example, dimethylamine is a metabolite of choline, a nutrient important for brain function.

However, it's worth noting that "dimethylamines" is not typically used as a medical term to describe a specific condition or diagnosis. If you have any concerns about exposure to dimethylamine or its potential health effects, it would be best to consult with a healthcare professional.

Chloroplasts are specialized organelles found in the cells of green plants, algae, and some protists. They are responsible for carrying out photosynthesis, which is the process by which these organisms convert light energy from the sun into chemical energy in the form of organic compounds, such as glucose.

Chloroplasts contain the pigment chlorophyll, which absorbs light energy from the sun. They also contain a system of membranes and enzymes that convert carbon dioxide and water into glucose and oxygen through a series of chemical reactions known as the Calvin cycle. This process not only provides energy for the organism but also releases oxygen as a byproduct, which is essential for the survival of most life forms on Earth.

Chloroplasts are believed to have originated from ancient cyanobacteria that were engulfed by early eukaryotic cells and eventually became integrated into their host's cellular machinery through a process called endosymbiosis. Over time, chloroplasts evolved to become an essential component of plant and algal cells, contributing to their ability to carry out photosynthesis and thrive in a wide range of environments.

Medical definitions of water generally describe it as a colorless, odorless, tasteless liquid that is essential for all forms of life. It is a universal solvent, making it an excellent medium for transporting nutrients and waste products within the body. Water constitutes about 50-70% of an individual's body weight, depending on factors such as age, sex, and muscle mass.

In medical terms, water has several important functions in the human body:

1. Regulation of body temperature through perspiration and respiration.
2. Acting as a lubricant for joints and tissues.
3. Facilitating digestion by helping to break down food particles.
4. Transporting nutrients, oxygen, and waste products throughout the body.
5. Helping to maintain healthy skin and mucous membranes.
6. Assisting in the regulation of various bodily functions, such as blood pressure and heart rate.

Dehydration can occur when an individual does not consume enough water or loses too much fluid due to illness, exercise, or other factors. This can lead to a variety of symptoms, including dry mouth, fatigue, dizziness, and confusion. Severe dehydration can be life-threatening if left untreated.

The term "Theoretical Models" is used in various scientific fields, including medicine, to describe a representation of a complex system or phenomenon. It is a simplified framework that explains how different components of the system interact with each other and how they contribute to the overall behavior of the system. Theoretical models are often used in medical research to understand and predict the outcomes of diseases, treatments, or public health interventions.

A theoretical model can take many forms, such as mathematical equations, computer simulations, or conceptual diagrams. It is based on a set of assumptions and hypotheses about the underlying mechanisms that drive the system. By manipulating these variables and observing the effects on the model's output, researchers can test their assumptions and generate new insights into the system's behavior.

Theoretical models are useful for medical research because they allow scientists to explore complex systems in a controlled and systematic way. They can help identify key drivers of disease or treatment outcomes, inform the design of clinical trials, and guide the development of new interventions. However, it is important to recognize that theoretical models are simplifications of reality and may not capture all the nuances and complexities of real-world systems. Therefore, they should be used in conjunction with other forms of evidence, such as experimental data and observational studies, to inform medical decision-making.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Macromolecular substances, also known as macromolecules, are large, complex molecules made up of repeating subunits called monomers. These substances are formed through polymerization, a process in which many small molecules combine to form a larger one. Macromolecular substances can be naturally occurring, such as proteins, DNA, and carbohydrates, or synthetic, such as plastics and synthetic fibers.

In the context of medicine, macromolecular substances are often used in the development of drugs and medical devices. For example, some drugs are designed to bind to specific macromolecules in the body, such as proteins or DNA, in order to alter their function and produce a therapeutic effect. Additionally, macromolecular substances may be used in the creation of medical implants, such as artificial joints and heart valves, due to their strength and durability.

It is important for healthcare professionals to have an understanding of macromolecular substances and how they function in the body, as this knowledge can inform the development and use of medical treatments.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the ... Light-harvesting complex Photosynthesis Photosystem Phycobilisome Photosynthetic reaction center protein family Berg JM, ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ... The reaction center found in Rhodopseudomonas bacteria is currently best understood, since it was the first reaction center of ...
The D1 and D2 proteins occur as a heterodimer that form the reaction core of PSII, a multisubunit protein-pigment complex ... Photosynthetic reaction centre proteins are main protein components of photosynthetic reaction centres (RCs) of bacteria and ... IPR005867 Photosystem II reaction centre protein PsbD/D2 InterPro: IPR005868 Photosynthetic reaction centre, L subunit InterPro ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ...
This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple ... "Structure of the protein subunits in the photosynthetic reaction centre of Rhodopseudomonas viridis at 3Å resolution". Nature. ... Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. ... Deisenhofer, J.; Epp, O.; Miki, K.; Huber, R.; Michel, H. (1984). "X-ray structure analysis of a membrane protein complex". ...
This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple ... "Structure of the protein subunits in the photosynthetic reaction centre of Rhodopseudomonas viridis at 3Å resolution". Nature. ... Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. ... a membrane-bound complex of proteins and co-factors that is essential to photosynthesis. Born in Bavaria, Deisenhofer earned ...
... palustris has genes that encode for proteins that make up light-harvesting complexes (LHCs) and photosynthetic reaction centers ... LHCs and photosynthetic reaction centers are typically found in photosynthetic organisms such as green plants. Moreover, R. ... in Chlorophyll and replaces it with its Vanadium center in order to attach and harvest energy via Light Harvesting Complexes ... R. palustris also has genes that encode for the protein ruBisCO, an enzyme necessary for carbon dioxide fixation in plants and ...
While carotenoids can be found complexed within chlorophyll-binding proteins such as the photosynthetic reaction centers and ... Pigment-protein complexes that are outside of the photosynthetic system are less common, but have a simpler structure. For ... In lobsters, there are various types of astaxanthin-protein complexes present. The first one is crustacyanin (max 632 nm), a ... Astaxanthin's color is formed by creating complexes with proteins in a certain order. For example, the crustochrin has ...
The complexes consist of proteins and photosynthetic pigments and surround a photosynthetic reaction center to focus energy, ... The LH1 complexes surrounds the reaction centre, while the LH2 complexes are arranged around the LH1 complexes and the reaction ... Photosynthesis Photosynthetic reaction center Photosystem II light-harvesting protein Light harvesting pigment Fassioli, ... A light-harvesting complex consists of a number of chromophores which are complex subunit proteins that may be part of a larger ...
1996 marked the publication of Schulten's model of the LH2 structure of the photosynthetic reaction centre protein family of ... 2015). Why More Is Different Philosophical Issues in Condensed Matter Physics and Complex Systems. Berlin Heidelberg: Springer- ... Schulten recognized that a successful attack on modeling the photosynthetic reaction center would require parallel computing ... Huber won the Nobel Prize in chemistry for determining the three-dimensional structure of the photosynthetic reaction center. ...
... bacteria are protein complexes responsible for the transfer of solar energy to the photosynthetic reaction centre. Purple ... also known as the core antenna complex) that is directly associated with the reaction centre, with the RC at the center of its ... It is one of the many independent types of light-harvesting complex used by various photosynthetic organisms. In photosynthetic ... Both the alpha and the beta chains of antenna complexes are small proteins of 42 to 68 residues which share a three-domain ...
... photosynthetic reaction center complex proteins MeSH D08.811.600.710.249 - light-harvesting protein complexes MeSH D08.811. ... photosystem i protein complex MeSH D08.811.600.710.750 - photosystem ii protein complex MeSH D08.811.600.715 - polyketide ... electron transport chain complex proteins MeSH D08.811.600.250.500 - electron-transferring flavoproteins MeSH D08.811.600.250. ... glycine decarboxylase complex h-protein MeSH D08.811.600.391.200 - glycine dehydrogenase (decarboxylating) MeSH D08.811.600.465 ...
Bacterial photosynthetic reaction centres and photosystems I and II Light harvesting complexes from bacteria and chloroplasts 4 ... Family 1.G.11 Poxvirus Cell Entry Protein Complex (PEP-C) Family 1.G.12 The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95 ... HBV-S Protein) Family 1.G.7 The Reovirus FAST Fusion Protein (R-FAST) Family 1.G.8 The Arenavirus Fusion Protein (AV-FP) Family ... Transport proteins, Transmembrane proteins, Protein classification, Biological databases). ...
Bacterial photosynthetic reaction centres and photosystems I and II Light-harvesting complexes from bacteria and chloroplasts ... In humans, 27% of all proteins have been estimated to be alpha-helical membrane proteins. Beta-barrel proteins are so far found ... A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many ... Membrane Proteins of known 3D Structure Elofsson, Arne; Heijne, Gunnar von (7 June 2007). "Membrane Protein Structure: ...
... and reaction centre components in the thylakoid membrane include a water-soluble peridinin-chlorophyll a-protein complex (PCP ... photosynthetic electron transport systems such as the photosystem II reaction centre and the chlorophyll-a-P700 reaction centre ... Response of chlorophyll-protein complexes to different photon-flux densities". Marine Biology. 130 (1): 23-33. doi:10.1007/ ... Spectroscopic properties of the Chlorophyll a-Chlorophyll c2-Peridinin-Protein-Complex (acpPC) from the coral symbiotic ...
The binding of the PsaC subunit to the PsaA and PsaB subunits of the photosynthetic reaction center, Photosystem I, has been ... "The Assembly of a Multisubunit Photosynthetic Membrane Protein Complex: A Site-Specific Spin Labeling EPR Spectroscopic Study ... The theory of SDSL is based on the specific reaction of spin labels with amino acids. A spin label's built-in protein structure ... The assembly of multi-subunit membrane protein complexes has also been studied using spin labeling. ...
... and similar proteins in the photosynthetic reaction center. The endosymbiotic theory suggests that photosynthetic bacteria were ... This complex is made up of a series of proteins with different pigments which surround the reaction center. As carbon dioxide ... DNA in chloroplasts codes for redox proteins such as those found in the photosynthetic reaction centers. The CoRR Hypothesis ... the process always begins when energy from light is absorbed by proteins called reaction centers that contain photosynthetic ...
PSII is a multisubunit protein-pigment complex containing polypeptides bound to the photosynthetic membrane. Within the core of ... which pass the excitation energy on to the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox- ... Photosystem II (PSII) has a P680 reaction centre containing chlorophyll 'a' that uses light energy to carry out the oxidation ( ... Photosystem I (PSI) has a P700 reaction centre containing chlorophyll that takes the electron and associated hydrogen donated ...
... needed to drive this electron transport chain come from light-gathering proteins called photosynthetic reaction centres. ... In animals, these reactions involve complex organic molecules that are broken down to simpler molecules, such as carbon dioxide ... Reaction centers are classified into two types depending on the nature of photosynthetic pigment present, with most ... This process uses the ATP and NADPH produced by the photosynthetic reaction centres, as described above, to convert CO2 into ...
... and similar proteins in the photosynthetic reaction center. The endosymbiotic theory suggests that photosynthetic bacteria were ... contributing to more complex morphogenesis of land plants. Evolutionary history of plants Annual vs. perennial plant evolution ... DNA in chloroplasts codes for redox proteins such as photosynthetic reaction centers. The CoRR hypothesis proposes that this Co ... Therefore, chloroplasts may be photosynthetic bacteria that adapted to life inside plant cells. Like mitochondria, chloroplasts ...
ATP synthase large DNA and protein complexes: nucleosome centriole and microtubule-organizing center (MTOC) cytoskeleton ... Purple bacteria have "chromatophores", which are reaction centers found in invaginations of the cell membrane. Green sulfur ... which are photosynthetic antenna complexes found bonded to cell membranes. Cyanobacteria have internal thylakoid membranes for ... Such cell structures include: large RNA and protein complexes: ribosome, spliceosome, vault large protein complexes: proteasome ...
Each transmembrane reaction center complex is associated with an antenna complex that has hundreds of light-harvesting pigment ... This was significant because it showed that it was possible to produce these proteins in situ where they could be used as ... In fact, a common feature of all photosynthetic machinery in bacteria, algae and plants is the existence of many antenna ... complexes that can absorb the light and transfer it to a transmembrane reaction center complex. The light-harvesting pigment ...
Reaction centers are multi-protein complexes found within the thylakoid membrane. At the heart of a photosystem lies the ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ... At the reaction center, there are many polypeptides that are surrounded by pigment proteins. At the center of the reaction ... and a reaction center. The antenna complex is where light is captured, while the reaction center is where this light energy is ...
The PSII oxygen-evolving complex (OEC) provides electrons to re-reduce the PSII reaction center, and oxidizes 2 water molecules ... is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. ... which pass the excitation energy on to chlorophylls in the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind ... In oxygen-evolving reaction centers, more than half of the cyt b559 is in the HP form. In manganese-depleted non-oxygen ...
... complex functions to mediate the transfer of electrons and of energy between the two photosynthetic reaction center complexes, ... Iron-sulfur proteins, Light reactions, Integral membrane proteins, EC 1.10.99). ... The reaction is analogous to the reaction catalyzed by cytochrome bc1 (Complex III) of the mitochondrial electron transport ... In a separate reaction, the cytochrome b6f complex plays a central role in cyclic photophosphorylation, when NADP+ is not ...
... role of electron shuttles in the cyclic electron flow between the photosynthetic reaction center and the cytochrome bc1 complex ... "Crystal structures of photosynthetic reaction center and high-potential iron-sulfur protein from Thermochromatium tepidum: ... HiPIPs take part in many oxidizing reactions in creatures, and are especially known with photosynthetic anaerobic bacteria, ... In contrast, the protein associated with the Fd's allows these clusters to contact solvent resulting in 8 protein H-bonding ...
Light-harvesting complexes are involved in the energy transfer to the reaction centre. These are integral membrane protein ... the photosynthetic unit which is composed by the light-harvesting complexes LHI and LHII and the photosynthetic reaction centre ... Light-harvesting complexes surrounding a reaction centre (RC) harvest photons in the form of resonance energy, exciting ... LHI is directly associated with the reaction centre forming a polymeric ring-like structure around it. LHI has an absorption ...
These genes code for photosynthetic reaction centers and other components of the photosynthetic electron transport chain. A ... genes most commonly retained in mitochondrial DNA fulfil central roles in the structure of their respective protein complexes, ... Most genes for proteins of chloroplasts and mitochondria are, however, now located on chromosomes in the nuclei of eukaryotic ... Different products of protein synthesis in isolated chloroplasts and mitochondria are obtained in the presence of redox ...
... of all proteins in the cell. Metals are known to be involved in over 40% of enzymatic reactions, and metal-binding proteins ... The incorporation of a manganese center in photosystem II was highly significant, as it allowed for photosynthetic oxygen ... The incorporation of Mn in proteins allowed the complexes the ability to reduce reactive oxygen species in Mn-superoxide ... They belong to a class of enzymes with a mononuclear Mo center and they catalyze the metabolism reaction of C, N, S, etc., in ...
Photosynthetic reaction center Pairs of bacteriochlorophylls (green) inside the membrane capture energy from sunlight, then ... Heterotrimeric G proteins 1996 - Green fluorescent protein 1996 - CDK/cyclin complex 1996 - Kinesin motor protein 1997 - GroEL/ ... Crystal structures of protein and nucleic acid molecules and their complexes are central to the practice of most parts of ... 1986 - Repressor/DNA interactions 1987 - Major histocompatibility complex' 1987 - Ubiquitin 1987 - ROP protein 1989 - HIV-1 ...
... that are carried out through pigment-protein complexes (e.g. Photosystem II). Pigment-protein complexes (PPC) contain ... The light-driven charge separation process occurs at the reaction center due to the cooperation of two porphyrin derivatives. ... The dynamic and efficient antenna complexes that are present in photosynthetic organisms has inspired the design of synthetic ... are light harvesting complex 1 and light harvesting complex 2. Light harvesting complex 2 in the purple bacteria Rhodoblastus ...
... photosynthetic reaction centers). There, the electric field which is formed in the reaction center, following the light induced ... such as proteins. The photoacoustic immunoassay labels and detects target proteins using nanoparticles that can generate strong ... The second mechanism shows up in photosynthetically active sub-cell complexes in suspension (e.g. ... The photoacoustic signal from preparations which carry out the primary electron transfer reactions (e.g. reaction centers) is a ...
The orientation of the principal axes of the primary electron donor triplet state measured in single crystals of photosynthetic ... reaction centers is compared to the x-ray structures of the bacteria Rhodobacter (Rb.) sphaeroides R-26 and Rhodopseudomonas ( ... Photosynthetic Reaction Center Complex Proteins Actions. * Search in PubMed * Search in MeSH ... Protein modifications affecting triplet energy transfer in bacterial photosynthetic reaction centers. Laible PD, Chynwat V, ...
... and Ubiquitin-Protein Ligase Complexes. Electron Transport Chain Complex Proteins and Photosynthetic Reaction Center Complex ... Angiogenic Proteins: A new descriptor class has been added for proteins that regulate the proliferation of new blood vessels. ... Amino Acids, Peptides and Proteins (D12): 246 new descriptors were added. Proteins and Enzymes: A total of 65 new enzyme ... Receptors, G-Protein-Coupled was added as new class to the Cell Surface Receptors. There are over 100 descriptors now re-treed ...
Photosynthetic Reaction Center Complex Proteins / metabolism* Actions. * Search in PubMed * Search in MeSH ... The HCF136 protein is essential for assembly of the photosystem II reaction center in Arabidopsis thaliana. Plücken H, Müller B ... This accumulation profile confirms the mutational data by showing that the HCF136 protein must be present when PSII complexes ... Immunoblot analysis of fractionated chloroplasts showed that the HCF136 protein is a lumenal protein, found only in stromal ...
Photosynthetic Reaction Center Complex Proteins D12.776.543.983.500 D12.776.543.930.500 Photosystem I Protein Complex D12.776. ... ELAV Proteins D12.776.641.520 D12.776.631.520 ELAV-Like Protein 2 D12.776.641.520.500 D12.776.631.520.500 ELAV-Like Protein 3 ... PrP 27-30 Protein D12.776.785.700.700 D12.776.785.340.750.700 PrPC Proteins D12.776.785.680 D12.776.785.340.500 PrPSc Proteins ... Photosystem II Protein Complex D12.776.543.983.500.750 D12.776.543.930.500.750 Phototrophic Processes G2.111.87.678 G2.111.669 ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Complex Photosynthetic Complexes Photosynthetic Reaction Center Photosynthetic Reaction Center Complex Protein ... Photosynthetic Reaction Center Complex Proteins [D12.776.543.930.500] * Cytochrome b6f Complex [D12.776.543.930.500.374] ... Photosynthetic Reaction Center Complex Proteins [D05.500.562.488] * Cytochrome b6f Complex [D05.500.562.488.374] ... Photosynthetic Reaction Center Complex Proteins [D08.811.600.710] * Cytochrome b6f Complex [D08.811.600.710.374] ...
Photosynthetic Complex Photosynthetic Complexes Photosynthetic Reaction Center Photosynthetic Reaction Center Complex Protein ... Photosynthetic Reaction Center Complex Proteins [D12.776.543.930.500] * Cytochrome b6f Complex [D12.776.543.930.500.374] ... Photosynthetic Reaction Center Complex Proteins [D05.500.562.488] * Cytochrome b6f Complex [D05.500.562.488.374] ... Photosynthetic Reaction Center Complex Proteins [D08.811.600.710] * Cytochrome b6f Complex [D08.811.600.710.374] ...
A-PROTEINS; CHLOROPHYLL AC-PROTEINS & LIGHT-HARVESTING CHLOROPHYLL PROTEIN use PHOTOSYNTHETIC REACTION CENTER COMPLEX PROTEINS ... for PHOTOSYSTEM I REACTION CENTER use PHOTOSYNTHETIC REACTION CENTER COMPLEX PROTEINS 1991-2003 BX - Photosystem I Reaction ... HN - 2004; for PHOTOSYSTEM II REACTION CENTER use PHOTOSYNTHETIC REACTION CENTER COMPLEX PROTEINS 1991-2003; for WATER- ... Photosynthetic Reaction Center Complex Proteins UI - D045322 MN - D8.811.600.710 MN - D12.776.758 MS - Protein complexes that ...
photosystem II manganese-stabilizing protein Medicine & Life Sciences 8% * Photosynthetic Reaction Center Complex Proteins ... is the plant photosynthetic reaction center that carries out the light driven oxidation of water. The water splitting reactions ... is the plant photosynthetic reaction center that carries out the light driven oxidation of water. The water splitting reactions ... is the plant photosynthetic reaction center that carries out the light driven oxidation of water. The water splitting reactions ...
Bacterial Reaction centers (bRCs) from photosynthetic bacteria are pigment-protein complexes responsible for initial charge ... 2D POLIM on protein aggregation. *Tracking energy transfer and charge separation within photosynthetic unit of green non-sulfur ... Energy and electron transfer in bacterial reaction centers. *Ultrafast coherence transfer in DNA-templated silver nanoclusters ... Exciton structure, energy transfer and coherence dynamics in the FMO complex. *Spectroscopy at the nanoscale in perovskite ...
Photosynthetic Reaction Center Complex Proteins D12.776.543.983.500 D12.776.543.930.500 Photosystem I Protein Complex D12.776. ... ELAV Proteins D12.776.641.520 D12.776.631.520 ELAV-Like Protein 2 D12.776.641.520.500 D12.776.631.520.500 ELAV-Like Protein 3 ... PrP 27-30 Protein D12.776.785.700.700 D12.776.785.340.750.700 PrPC Proteins D12.776.785.680 D12.776.785.340.500 PrPSc Proteins ... Photosystem II Protein Complex D12.776.543.983.500.750 D12.776.543.930.500.750 Phototrophic Processes G2.111.87.678 G2.111.669 ...
Bacterial photosynthetic membrane proteins, light-harvesting antenna complex (LH1), reaction center (RC), and their combined ... The 14-3-3 proteins form a highly conserved family of dimeric proteins that interact with various signal transduction proteins ... Molecular assembly of artificial photosynthetic antenna core complex on an amino-terminated ITO electrode. ... core complex (LH1-RC) are functional elements in the primary photosynthetic events, i.e., capturing and transferring light ...
Photosynthetic Reaction Center Complex Proteins. *Polyketide Synthases. *Prostaglandin-Endoperoxide Synthases. *Proteasome ... Enzyme complexes that catalyze the formation of PROSTAGLANDINS from the appropriate unsaturated FATTY ACIDS, molecular OXYGEN, ...
Photosynthetic Reaction Center Complex Proteins. Complexo de Proteínas do Centro de Reação Fotossintética. Proteínas del ... Cullin Proteins. Proteínas Culina. Proteínas Cullin. Cytochrome b6f Complex. Complexo Citocromos b6f. Complejo de Citocromo b6f ... Electron Transport Chain Complex Proteins. Complexo de Proteínas da Cadeia de Transporte de Elétrons. Proteínas del Complejo de ... F-Box Proteins. Proteínas F-Box. Proteínas F-Box. GTP-Binding Protein beta Subunits. Subunidades beta da Proteína de Ligação a ...
Photosynthetic Reaction Center Complex Proteins. Complexo de Proteínas do Centro de Reação Fotossintética. Proteínas del ... Cullin Proteins. Proteínas Culina. Proteínas Cullin. Cytochrome b6f Complex. Complexo Citocromos b6f. Complejo de Citocromo b6f ... Electron Transport Chain Complex Proteins. Complexo de Proteínas da Cadeia de Transporte de Elétrons. Proteínas del Complejo de ... F-Box Proteins. Proteínas F-Box. Proteínas F-Box. GTP-Binding Protein beta Subunits. Subunidades beta da Proteína de Ligação a ...
Of particular interest is energy and electron transfer in photosynthetic light-harvesting complexes and reaction centers, which ... We employ 2DES for studying photosynthetic chromophore-protein complexes, artificial molecules and nanostructures. We aim at ... Lund Laser Centre. Lund University. Visiting address: Professorsgatan 1. Postal address: Box 118, 221 00 Lund, Sweden. +46 46 ... These properties make 2DES the method of choice when exploring the light-triggered processes in complex systems. ...
Photosynthetic Reaction Center Complex Proteins N0000170204 Photosystem I Protein Complex N0000170202 Photosystem II Protein ... Complex 1 N0000168711 Adaptor Protein Complex 2 N0000168710 Adaptor Protein Complex 3 N0000168702 Adaptor Protein Complex 4 ... Adaptor Protein Complex alpha Subunits N0000168708 Adaptor Protein Complex beta Subunits N0000168704 Adaptor Protein Complex ... Adaptor Protein Complex gamma Subunits N0000168707 Adaptor Protein Complex mu Subunits N0000168705 Adaptor Protein Complex ...
Structure of the photosynthetic reaction center from Rhodobacter sphaeroides at 2.65 Å resolution: cofactors and protein- ... Buchanan, S.K. & Dismukes, G.C. (1987). Substitution of Cu2+ in the reaction center diquinone electron acceptor complex of ... Buchanan, S.K., Fritzsch, G., Ermler, U. & Michel, H. (1993). A new crystal form of the photosynthetic reaction centre from ... Gerwert, K., Hess, B., Michel, H. & Buchanan, S. (1988). FTIR studies on crystals of photosynthetic reaction centers. FEBS Lett ...
High quality crystals of Porin from R. capsulatus and the photosynthetic reaction center from Rhodopseudomonas viridis were ... Protein-Protein co-complexes have also been successfully pursued by the SGC using co-expression to identify protein partners (i ... In 2007, RIKEN will launch a new structural proteomics initiative with focus on protein-protein complexes and protein targets ... Once again the crystal structure of the complex revealed a Tyr-rich protein-protein interface. The bottlenecks for the ...
... where they undergo a complex series of electrochemical reactions known collectively as oxidative phosphorylation. These aerobic ... Currie H, Vrana J, Han A, Scardoni G, Boggs N and Boyd J (2014) An Approach to Investigate Intracellular Protein Network ... Now photosynthetic algae were on the scene, and they were filling the atmosphere with oxygen. The appearance of oxygen was ... Mitochondria can be thought of as processing centers on a path that begins with sunlight and ends with ATP. All the energy on ...
Characterization of the functional changes and the darkand light-adapted reaction center states of Photosystem II core complex ... předsedající, International Workshop on Photosynthetic Proteins, Szeged. 2015. člen komise, Hodnocení ústavů a výzkumných ... Fine-Tuning of the Structure and Function of Light-Harvesting Complex II and the Reaction Center ... Light-induced conformational changes in closed Photosystem II reaction center complexes alter the excitation energy pathways ...
Proteins containing photosynthetic reaction centre domains modulate FtsZ-based archaeal cell division. Nußbaum P, Kureisaite- ... phosphorylation by chemical modulators of the phosphatase PP1 in complex cellular contexts. Hoermann B, Dürr EM, Ludwig C, ...
Research Interests: The development of protein-protein docking methods, and techniques combining machine learning and molecular ... Linker of the Nucleoskeleton and Cytoskeleton complex (LINC) cell biology *The role of the cytoskeleton and spectrin-family of ... Mechanistic studies of catalytic reactions (kinetics, modern physical organic chemistry, NMR spectroscopy) ... Electronic energy transfer in photosynthetic systems Professor Bernard Piette, Department of Mathematical Sciences Areas of ...
Effect of Dielectric Relaxation on the Kinetics of Electron Transfer in Photosynthetic Reaction Centers. Cherepanov, Dmitry A ... G protein-coupled receptors of class A harness the energy of membrane potential to increase their sensitivity and selectivity. ... Evolution of cytochrome bc complexes: From membrane-anchored dehydrogenases of ancient bacteria to triggers of apoptosis in ... Proton transfer in the photosynthetic reaction center of Blastochloris viridis. Kozlova, Maria A.; Juhnke, Hanno D.; Cherepanov ...
PMID- 670216 TI - A soluble lipid.protein complex from bovine adrenal medulla chromaffin granules. AB - A unique soluble ... Its bending strength was increased 40 to 80 per cent and its torsional rigidity was increased 230 to 3,000 per cent compared ... complex of the B isomer of ATPbetaS is now established by its stereospecificity in the hexokinase reaction. PMID- 670167 TI - ... The cytochrome may be considered to be a photosynthetic cytochrome of the f type. Cytochromes of the B type were also found in ...
... pyrrole biosynthesis gained from the crystal structure of flavin-dependent oxidase in complex with carrier protein. ... Centers for Oceans and Human Health and individual Oceans, Great Lakes, and Human Health research projects. 2021. *Aluru N, ... Enzymatic halogenation and dehalogenation reactions: pervasive and mechanistically diverse. Chem Rev 117(8):5619-5674.] ... Cell cycle regulation of the mixotrophic dinoflagellate Dinophysis acuminata: Growth, photosynthetic efficiency and toxin ...
protein-containing complex. IEP. Neighborhood. CC. GO:0033177. proton-transporting two-sector ATPase complex, proton- ... photosystem II reaction center. IEP. Neighborhood. CC. GO:0009579. thylakoid. IEP. Neighborhood. ... photosynthetic electron transfer D. 0.49. Archaeplastida. Gb_03953. No alias. component PetD/IV of cytochrome b6/f complex. ... Cytochrome b6-f complex subunit 4 OS=Pinus thunbergii.... 0.1. Archaeplastida. Pp3c21_5670V3.1. No alias. photosynthetic ...
The latter is achieved in a protein complex called the reaction center, but for this purpose the electronic excitation needs to ... More details can be found on our photosynthetic core complex website and in a previous highlight on PufX. ... travel from the chlorosome to the reaction center through a protein complex called the Fenna-Matthews-Olson (FMO) protein. FMO ... MDFF has been applied successfully to three highly symmetric multi-protein systems: (i) GroEL-GroES, a protein complex that ...
... in animals and fungi all these fatty acid synthase reactions are carried out by a single multifunctional protein,[84] while in ... "Cyberlipid Center. Archived from the original on 13 October 2017. Retrieved 1 December 2017.. ... Examples of these are the simple and complex glycosphingolipids such as cerebrosides and gangliosides. ... components of membranes of chloroplasts and related organelles and are among the most abundant lipids in photosynthetic tissues ...
Centers of Excellence on Environmental Health Disparities Research. *Collaborative Centers in Childrens Environmental Health ... Role of programmed cell death protein-1 and lymphocyte specific protein tyrosine kinase in the aryl hydrocarbon receptor- ... Monitoring for Complex Mixtures of Estrogen Agonists in the Aquatic Environment: Development of Biomarkers and in vitro Assays ... The reaction of ozone with benzo[a]anthracene. In: Proceedings of the IOA (International Ozone Association) Pan American ...
  • a protein complex (called a photosynthetic reaction centre) that is essential to photosynthesis in certain bacteria. (britannica.com)
  • Reaction centers are present in all green plants, algae, and many bacteria. (wikipedia.org)
  • The reaction center found in Rhodopseudomonas bacteria is currently best understood, since it was the first reaction center of known structure and has fewer polypeptide chains than the examples in green plants. (wikipedia.org)
  • In the 1960s, Roderick Clayton was the first to purify the reaction center complex from purple bacteria. (wikipedia.org)
  • The latter sub-unit is not a general structural motif in photosynthetic bacteria. (wikipedia.org)
  • They are found in plants and photosynthetic bacteria, and have evolved into two types. (psu.edu)
  • Certain photophysical characteristics of these triads, including the sequential electron transfer and the triplet energy-transfer relay mechanism, are reminiscent of those observed in natural reaction centers of photosynthetic bacteria. (elsevierpure.com)
  • The photosynthetic reaction center of purple bacteria is a multimeric, membraneassociated protein/chromophore complex. (tdl.org)
  • The photosynthetic reaction centers of purple bacteria have been well characterized, and all of them contain three subunits that are designated as L (light), M (medium), H (heavy). (tdl.org)
  • Bacterial Reaction centers (bRCs) from photosynthetic bacteria are pigment-protein complexes responsible for initial charge separation steps of photosynthesis. (lu.se)
  • Here, we analyzed native RC-LH (nRC-LH) and Car-depleted RC-LH (dRC-LH) complexes in Roseiflexus castenholzii , a chlorosome-less filamentous anoxygenic phototroph that forms the deepest branch of photosynthetic bacteria. (rcsb.org)
  • A light-harvesting complex has a complex of subunit proteins that may be part of a larger supercomplex of a photosystem, the functional unit in photosynthesis.It is used by plants and photosynthetic bacteria to collect more of the incoming light than would be captured by the photosynthetic reaction center alone. (connectwelch.com)
  • The reaction-center light-harvesting complex 1 (RC-LH1) is the core photosynthetic component in purple phototrophic bacteria. (liverpool.ac.uk)
  • The bacterial photosynthetic reaction center has been an important model to understand the structure and chemistry of the biological process of capturing light energy. (wikipedia.org)
  • Reaction centers from different bacterial species may contain slightly altered bacterio-chlorophyll and bacterio-pheophytin chromophores as functional co-factors. (wikipedia.org)
  • This study reveals the structural basis by which Cars assembly regulates the architecture and quinone exchange of bacterial RC-LH complexes. (rcsb.org)
  • Green plants and algae have two different types of reaction centers that are part of larger supercomplexes known as P700 in Photosystem I and P680 in Photosystem II. (wikipedia.org)
  • Photosystem I and II are two types of reaction centers found in thylakoid membranes, which are the sites of protein synthesis located in the leaves of plants. (anthana.nl)
  • Chlorophyll and pheophytin are the pigments found in a reaction centre. (biologyreader.com)
  • The energy culminates in a molecule of chlorophyll found in the reaction center. (connectwelch.com)
  • Antenna complex includes chlorophyll, accessory pigments and some protein. (connectwelch.com)
  • Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. (connectwelch.com)
  • The function of D1‐H332 in Photosystem II electron transport studied by thermoluminescence and chlorophyll fluorescence in site‐directed mutants of Synechocystis 6803 Yagut Allahverdiyeva Institute of Plant Biology, Biological Research Center, Szeged, Hungary Role of phosphatidylglycerol in the function and assembly of Photosystem II reaction center, studied in a cdsA-inactivated PAL mutant strain of Synechocystis sp. (anthana.nl)
  • In the PSII reaction centre, singlet oxygen is generated by the interaction of molecular oxygen with the excited triplet state of chlorophyll (Chl). (anthana.nl)
  • Chromophores chlorophyll a (red) and chlorophyll b (teal) are embedded in three protein subunits (dark purple, light purple, and gray) in the light-harvesting complex of photosystem II. (acs.org)
  • The chromophores absorb light and funnel the energy to a separate chlorophyll-protein complex known as the reaction center, which transforms the energy into chemical form. (acs.org)
  • PS II chlorophyll antenna complex transfer this energy to the reaction center and then from the reaction center to the primary electron acceptor. (yourlearningpoint.com)
  • These findings mark an important step forward in understanding the evolution and diversity of prokaryotic photosynthetic apparatus. (rcsb.org)
  • In particular, intracytoplasmic membrane vesicles (chromatophores) from the purple bacterium Rhodospirillum rubrum provide a fully functional and robust photosynthetic apparatus, ideal for biophysical investigations of energy transduction and incorporation into biohybrid photoelectrochemical devices. (researchwithrutgers.com)
  • Under these conditions, there is an imbalance between the light absorbed and utilized, provoking the over-excitation of the photosynthetic apparatus and increasing the risk of photooxidative damage. (frontiersin.org)
  • High-light illumination of photosynthetic organisms stimulates the production of singlet oxygen by photosystem II (PSII) and causes photo-oxidative stress. (anthana.nl)
  • Photosystem II Dimer Created by: Rebecca Babski Photosystem II (PDB ID: 3bz1) is a homodimer protein complex that is present in the thylakoid membrane of many photosynthesizing organisms including plants, green algae, and cyanobacteria (1). (anthana.nl)
  • Historically, the earliest photosynthetic organisms likely utilized reducing agents such as hydrogen or hydrogen sulfide. (microbiologynote.com)
  • Furthermore, photosynthetic organisms assimilate between 100-115 billion tons of carbon annually. (microbiologynote.com)
  • But evidence is mounting that photosynthetic organisms may, in fact, capitalize on quantum effects to harness the sun's rays. (acs.org)
  • One of the most challenging stressors for photosynthetic organisms living in temperate regions is photochilling. (frontiersin.org)
  • To tolerate this combined stress, photosynthetic organisms need protective physiological and morphological mechanisms. (frontiersin.org)
  • 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. (wikipedia.org)
  • The dark reaction of photosynthesis refers to the phase that doesn't need light energy or photons to complete the cycle and hence also called the light-independent photosynthetic phase. (biologyreader.com)
  • Carotenoid (Car) pigments perform central roles in photosynthesis-related light harvesting (LH), photoprotection, and assembly of functional pigment-protein complexes. (rcsb.org)
  • Photosystem is the unit responsible for photosynthesis and consists of reaction center pigment and antenna complex. (connectwelch.com)
  • Series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions Light energy is absorbed by ______ in the pigments found in … In the first part of photosynthesis, the light-dependent reaction, pigment molecules absorb energy from sunlight. (connectwelch.com)
  • light-dependent reactions: the first set of reactions in photosynthesis that use energy from sunlight to produce ATP and NADPH. (connectwelch.com)
  • Nature, through centuries of evolution, has perfected the harvesting of light for energy conversion through the process of photosynthesis by employing two main mechanisms carried out by distinct proteins: excitation energy transfer, where light harvesting complexes capture light from multiple regions of the solar spectrum and funnel photoexcitations to a reaction center, and charge separation, where the photoexcitations become free charges in the reaction center. (suny.edu)
  • Notably, photosynthesis plays a pivotal role in sustaining Earth's atmospheric oxygen levels and furnishing the majority of biological energy requisite for Earth's complex life forms. (microbiologynote.com)
  • Regardless of the organism or method, photosynthesis invariably commences with the absorption of light energy by proteins known as reaction centers, which contain photosynthetic pigments or chromophores. (microbiologynote.com)
  • Few scientists would look for quantum mechanics at work in machinery as complex as that of photosynthesis, with multitudes of jiggling, membrane-bound proteins anchoring even more light-absorbing chromophores. (acs.org)
  • Their simple structure as well as high energy and charge transfer efficiency, which are not fully understood yet, makes bRCs one of the most important and most investigated photosynthetic systems in the world. (lu.se)
  • A reaction center is laid out in such a way that it captures the energy of a photon using pigment molecules and turns it into a usable form. (wikipedia.org)
  • Once the light energy has been absorbed directly by the pigment molecules, or passed to them by resonance transfer from a surrounding light-harvesting complex, they release electrons into an electron transport chain and pass energy to a hydrogen donor such as H2O to extract electrons and protons from it. (wikipedia.org)
  • The light harvesting complex is composed of (3 and a proteins, to which are bound pigment molecules. (tdl.org)
  • We employ 2DES for studying photosynthetic chromophore-protein complexes, artificial molecules and nanostructures. (lu.se)
  • The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem. (connectwelch.com)
  • Subsequently, these energy-rich cofactors participate in the Calvin Cycle, a series of reactions that facilitate the synthesis of organic molecules by assimilating carbon atoms from carbon dioxide (CO2). (microbiologynote.com)
  • The development of a Rhodobacter sphaeroides deletion/plasmid complementation system of the puhA gene (which encodes the reaction center [RC] heavy [H] subunit) for expression of site directed mutants of the RC H protein is described. (ubc.ca)
  • We also assigned amino acid sequences of subunit X and two hypothetical proteins Y and Z that functioned in forming the quinone channel and stabilizing the RC-LH interactions. (rcsb.org)
  • W complex consists of an open 14-subunit LH1 ring surrounding the RC interrupted by protein-W, whereas the complex without protein-W at 2.80-Å resolution comprises an RC completely encircled by a closed, 16-subunit LH1 ring. (liverpool.ac.uk)
  • These proteins anchor masses of chromophores such as chlorophylls, linear tetrapyrroles, and carotenoids. (acs.org)
  • 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. (wikipedia.org)
  • To answer these questions, photosynthetic fluorescence measurements as well as pigment and low molecular weight carbohydrate pool analyses were performed under controlled laboratory conditions. (frontiersin.org)
  • The reaction center contains two pigments that serve to collect and transfer the energy from photon absorption: BChl and Bph. (wikipedia.org)
  • Absorption spectroscopy showed this strain has a reduction in the amount of the light-harvesting I (LHI) complex. (ubc.ca)
  • The difference between photosystem I and photosystem II is primarily due to the difference in active reaction centre and photon absorption. (biologyreader.com)
  • It comprises protein pigments that mediates light absorption and excitation of an electron to the higher energy state. (biologyreader.com)
  • The function of the photosynthetic reaction center is to catalyze light-driven electron transfer across the photosynthetic membranes. (tdl.org)
  • Here, we present data that fully characterize the structural and functional properties of PSII complexes in isolated PSII-enriched membranes from C. reinhardtii. (anthana.nl)
  • The Cytochrome b Group refers to a category of proteins involved in the electron transport chain, specifically containing heme b as a cofactor, which facilitates the transfer of electrons and contributes to the production of ATP during cellular respiration. (lookformedical.com)
  • During the light reactions, the pigments and proteins of _____ use light to send energized electrons through an electron transport chain, ult … imately producing _____ (a form of energy). (connectwelch.com)
  • During the light-dependent reactions, electrons are extracted from substances like water, resulting in the release of oxygen gas. (microbiologynote.com)
  • The area which takes electrons (energy)k from the antenna complex and starts the light reaction is called the reaction center. (yourlearningpoint.com)
  • During this flow of electrons following reactions take place. (yourlearningpoint.com)
  • Type II reaction centers employ a mobile quinone as the terminal electron acceptor. (psu.edu)
  • However, the relationships between Car depletion in the LH, assembly of the prokaryotic reaction center (RC)-LH complex, and quinone exchange are not fully understood. (rcsb.org)
  • The structurally unique protein-W prevents LH1 ring closure, creating a channel for accelerated quinone/quinol exchange. (liverpool.ac.uk)
  • It is an aerobic process that involves two successive oxidation reactions, in which the ammonia first oxidizes into nitrites, and then nitrites get oxidized into nitrates. (biologyreader.com)
  • The reduced form of cytochrome b5 donates an electron to various enzymes involved in oxidation-reduction reactions. (lookformedical.com)
  • Virtually all of the O2 in the atmosphere is produced by the photosynthetic oxygen evolving complex, a Mn/Ca/Cl cluster that catalyzes the oxidation of H2O to O2. (umich.edu)
  • Type I reaction centers employ an interpolypeptide [4Fe-4S] cluster (F X ) as an intermediate electron acceptor and two [4Fe-4S] iron-sulfur clusters (F A and F B ) as the terminal electron acceptors. (psu.edu)
  • Light reactions encompass two photosystems that are present in the thylakoid of chloroplasts. (connectwelch.com)
  • The LH1 protein is responsible for collecting visible and near-IR radiant energy and funneling these excitations to the reaction center for conversion into a transmembrane charge separation. (researchwithrutgers.com)
  • Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. (umassmed.edu)
  • Currently, we are studying manganese redox enzymes and zinc containing proteins. (umich.edu)
  • The enzymes, which are involved in a number of critical reactions, ranging from homocysteine homeostasis to protein farnesylation to alkene metabolism, generally contain thiolate-rich Zn sites. (umich.edu)
  • An artificial photosynthetic reaction center consisting of a carotenoid (C), a dimesitylparphyrin (P), and a bis(heptafluoropropyl)-porphyrin (P F ), C-P-P F , and the related triad in which the central porphyrin has been metalated to give C-P Zn -P F have been synthesized and characterized by transient spectroscopy. (elsevierpure.com)
  • P700 is the active reaction centre of PS-I, while P680 is the active reaction centre of PS-II. (biologyreader.com)
  • Photosynthetic reaction centers are also associated with light harvesting complexes, that absorb light energy and transfer it to the bacteriochlorophyll dimer ("special pair") that serves as the primary electron donor in the reaction center. (tdl.org)
  • The electron transport chain is a series of protein complexes in the inner mitochondrial membrane that generates most of the ATP (adenosine triphosphate) required for cellular energy production. (lookformedical.com)
  • Cytochromes b are a group of heme-containing proteins located in the inner mitochondrial membrane that function as electron carriers in the respiratory chain, playing a crucial role in cellular energy production through oxidative phosphorylation. (lookformedical.com)
  • Of particular interest is energy and electron transfer in photosynthetic light-harvesting complexes and reaction centers, which demonstrate remarkable efficiency and robustness. (lu.se)
  • The remaining function of the light-dependent reaction is to generate the other energy-carrier molecule, NADPH. (connectwelch.com)
  • Describe the pathway of energy in light-dependent reactions. (connectwelch.com)
  • This energy then excites an electron in the reaction center causing it to break free and be passed to the primary electron acceptor. (connectwelch.com)
  • Owing to the considerable current interest in replacing fossil fuels with solar radiation as a clean, renewable, and secure energy source, light-driven electron transport in natural photosynthetic systems offers a valuable blueprint for conversion of sunlight to useful energy forms. (researchwithrutgers.com)
  • In the photosystem, the part which absorbs light energy is called the antenna complex. (yourlearningpoint.com)
  • As we will see in this dissertation, SWCNTs have similar properties to that of photosynthetic systems, one of which is the varying chiralities of SWCNTs with different diameters, analogous to the distinct proteins in photosynthetic systems absorbing light at different wavelengths. (suny.edu)
  • A variety in light-harvesting complexes exist across the photosynthetic species. (wikipedia.org)
  • The photosynthetic alga has a highly diverse in species. (anthana.nl)
  • The replacing of the electron enables the reaction center to respond to another photon. (connectwelch.com)
  • Cytochromes b are a group of electron transport proteins that contain a heme c group, which is the prosthetic group responsible for their redox activity. (lookformedical.com)
  • Cytochromes are hemoproteins involved in electron transport chains, playing a crucial role in redox reactions during cellular respiration and metabolism, with their name deriving from the Greek words "kytos" (cell) and "chroma" (color), referring to the colored nature of these proteins due to the heme group. (lookformedical.com)
  • This structure allows cytochromes to participate in redox reactions, acting as electron carriers in various biological processes. (lookformedical.com)
  • From photosystem II, the excited electron travels along a series of proteins. (connectwelch.com)
  • One of the components of the core complex of photosystem II (PSII). (anthana.nl)
  • The extrinsic proteins of photosystem II (PS II) are also rich in diversity. (anthana.nl)
  • ATP synthase: the thylakoid membrane contains a protein called ____ _____ that spans the membrane and allows H+ ions to pass through it. (connectwelch.com)
  • Photosynthetic pigments are organized into clusters called photosystems in the thylakoid membrane. (yourlearningpoint.com)
  • These properties make 2DES the method of choice when exploring the light-triggered processes in complex systems. (lu.se)
  • We fabricate photovoltaic diodes mimicking photosynthetic systems. (suny.edu)
  • Using the analogy to photosynthetic systems, we use the smallest bandgap s-SWCNT network to create the diode (Reaction Center). (suny.edu)
  • We recognize that one of the primary limitations of the big data era to understand complex biological systems is the reliance on incomplete genome annotations. (wisc.edu)
  • They may help to make the light-harvesting systems robust, or they may impart yet-to-be-discovered qualities to the photosynthetic system. (acs.org)
  • Four different subunits were found to be important for the function of the photosynthetic reaction center. (wikipedia.org)
  • My background is mainly in structural biology (biomolecular crystallography and cryo electron-microscopy) where I developed methodology for 3D reconstruction of biomolecular complexes. (lu.se)
  • Strain ΔPUHA was unable to grow under photosynthetic conditions. (ubc.ca)
  • SDS-PAGE analysis of chromatophore proteins of strain ΔPUHA confirmed the absence of the RC H protein band. (ubc.ca)
  • Photosynthetic reaction centers are membrane-bound pigment-protein complexes that use light to catalyze a transmembrane electron transfer against a steep thermodynamic gradient. (psu.edu)
  • Metalloenzymes (proteins with metals at their active sites) catalyze reactions with a speed and selectivity that is unrivaled by conventional catalysts. (umich.edu)
  • The cytochromes b are part of Complex III, also known as the cytochrome bc1 complex or ubiquinol-cytochrome c reductase, in the ETC. In this complex, they function as electron carriers between ubiquinone (Q) and cytochrome c, participating in the process of oxidative phosphorylation to generate ATP. (lookformedical.com)
  • The hydrogen ions play critical roles in the remainder of the light-dependent reactions. (connectwelch.com)
  • It consists of a forward reaction comprising two de-epoxidation steps, in which the di-epoxy xanthophyll violaxanthin (V) is converted to the epoxy-free zeaxanthin (Z). The intermediate product of this reaction sequence is antheraxanthin (A), which contains one epoxy group. (frontiersin.org)
  • The pigments are arrayed in the protein complexes of the photosystems and also in antenna complexes or light harvesting complexes. (connectwelch.com)
  • Multienzyme Complexes" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (umassmed.edu)
  • Cytochrome b5 is a small heme protein found in the endoplasmic reticulum and mitochondrial inner membrane, involved in various electron transfer processes, including fatty acid desaturation, steroid metabolism, and microsomal mixed-function oxidase activities. (lookformedical.com)
  • Cytochrome c: a small, mobile protein found in the inner mitochondrial membrane that plays a crucial role in the electron transport chain during cellular respiration. (lookformedical.com)