where do cells get energy for active transport
cellular energy
1287541
their higher concentration—against the concentration gradient or other obstructing factor. Unlike passive transport, which uses the kinetic energy and natural entropy of molecules moving down a gradient, active transport uses cellular energy to move them against a gradient, polar repulsion, or other resistance. Active transport is usually associated with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acids. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport. Secondary active transport involves the use of an electrochemical gradient. Examples of active transport include the uptake
Active transport
1287562
neurotransmitters across a synapse between brain cells. Active transport In cellular biology, active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient. An example of active transport in human physiology is the uptake of glucose in the intestines. Active transport is the movement of molecules across a membrane from a region of
Active transport
1287541
their higher concentration—against the concentration gradient or other obstructing factor. Unlike passive transport, which uses the kinetic energy and natural entropy of molecules moving down a gradient, active transport uses cellular energy to move them against a gradient, polar repulsion, or other resistance. Active transport is usually associated with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acids. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport. Secondary active transport involves the use of an electrochemical gradient. Examples of active transport include the uptake
Active transport
15907499
cells to hold them together to form tissues. Fungi, bacteria, most archaea, and plants also have a cell wall, which provides a mechanical support to the cell and precludes the passage of larger molecules. The cell membrane is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport of materials needed for survival. The movement of substances across the membrane can be either "passive", occurring without the input of cellular energy, or "active", requiring the cell to expend energy in transporting it. The membrane also maintains the cell potential. The cell membrane thus works
Cell membrane
1287540
Active transport In cellular biology, active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient. An example of active transport in human physiology is the uptake of glucose in the intestines. Active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of
Active transport
313267
tripolyphosphate made from phosphoric acid is used in laundry detergents in some countries, but banned for this use in others. This compound softens the water to enhance the performance of the detergents and to prevent pipe/boiler tube corrosion. Inorganic phosphorus in the form of the phosphate is required for all known forms of life. Phosphorus plays a major role in the structural framework of DNA and RNA. Living cells use phosphate to transport cellular energy with adenosine triphosphate (ATP), necessary for every cellular process that uses energy. ATP is also important for phosphorylation, a key regulatory event in cells. Phospholipids
Phosphorus
3066036
membrane will depend on: In active transport a solute is moved against a concentration or electrochemical gradient; in doing so the transport proteins involved consume metabolic energy, usually ATP. In primary active transport the hydrolysis of the energy provider (e.g. ATP) takes place directly in order to transport the solute in question, for instance, when the transport proteins are ATPase enzymes. Where the hydrolysis of the energy provider is indirect as is the case in secondary active transport, use is made of the energy stored in an electrochemical gradient. For example, in co-transport use is made of the gradients of
Membrane transport
1287554
in "Nicotiana tabacum" BY2 cells and is expressed in the presence of microbial elicitors. NtPDR1 is localized in the root epidermis and aerial trichomes of the plant. Experiments using antibodies specifically targeting NtPDR1 followed by Western blotting allowed for this determination of localization. Furthermore, it is likely that the protein NtPDR1 actively transports out antimicrobial diterpene molecules, which are toxic to the cell at high levels. In secondary active transport, also known as "coupled transport" or "cotransport", energy is used to transport molecules across a membrane; however, in contrast to primary active transport, there is no direct coupling of ATP;
Active transport
8008483
glucose uptake. Facilitated diffusion can occur between the bloodstream and cells as the concentration gradient between the extracellular and intracellular environments is such that no ATP hydrolysis is required. However, in the kidney, glucose is reabsorbed from the filtrate in the tubule lumen, where it is at a relatively low concentration, passes through the simple cuboidal epithelia lining the kidney tubule, and into the bloodstream where glucose is at a comparatively high concentration. Therefore, the concentration gradient of glucose opposes its reabsorption, and energy is required for its transport. The secondary active transport of glucose in the kidney is Na
Glucose uptake
17815074
The nucleus of the dark cell is displaced toward the surface. Vestibular dark cells transport potassium into the inner ear endolymph, a potassium-rich fluid whose homeostasis is essential for hearing and balance. Dark cell regions of the vestibular system are involved in active (energy consuming) ion transport to maintain the unusual endolymph composition. In other words, dark cells utilize the Na/K-ATPase pump in order to transport potassium. As mentioned in dark cell structure, the basolateral membranes of vestibular dark cells are highly folded, allowing the enclosure of the numerous large mitochondria, and they contain high levels of Na/K-ATPase in both
Dark cell
3874092
Direct methanol fuel cell Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions. Efficiency is quite low for these cells, so they are targeted especially to portable applications, where energy and power density are more important than efficiency. A more efficient version of a direct fuel cell would play a key role in the theoretical use of methanol as a general energy transport medium, in the hypothesized methanol economy.
Direct methanol fuel cell
8094837
Efflux (microbiology) Active efflux is a mechanism responsible for moving compounds, like neurotransmitters, toxic substances, and antibiotics, out of cells; a process considered to be a vital part of xenobiotic metabolism. This mechanism is important in medicine as it can contribute to bacterial antibiotic resistance. Efflux systems function via an energy-dependent mechanism (active transport) to pump out unwanted toxic substances through specific efflux pumps. Some efflux systems are drug-specific, whereas others may accommodate multiple drugs with small multidrug resistance (SMR) transporters. Efflux pumps are proteinaceous transporters localized in the cytoplasmic membrane of all kinds of cells. They are active transporters,
Efflux (microbiology)
5280966
sieve tube elements. The companion cells also allow for bidirectional flow. While sieve tube members are responsible for a lot of the signaling necessary for the plant's organs, only some proteins are active within the sieve tubes. This is due to the fact that sieve tube members do not have ribosomes to synthesize protein as this makes it harder to determine which active proteins are specifically related to the sieve tube elements. Sieve tube members and companion cells are connected through plasmodesmata. Plasmodesmata consists of channels between cell walls of adjacent plant cells for transport and cell to cell recognition.
Sieve tube element
1851842
good "marker" of hypoxia, but lactate itself is not the cause of low pH. During exercise and some illnesses, lactate production is not generated by lack of oxygen, "per se", but by the catecholamine-driven metabolism of glucose (glycolysis) that cells use when they cannot get enough energy from oxygen-based reactions. Lactate serves as an energy source for other tissues. Lactic acidosis sometimes occurs without hypoxia, for example, in rare inborn errors of metabolism where mitochondria do not function at full capacity. In such cases, when the body needs more energy than usual, for example during exercise or disease, mitochondria cannot
Lactic acidosis
7355226
induction of a system whereby the cells can reduce the intracellular acid accumulation. According to Warth (1977), "Z. bailii" uses an inducible, active transport pump to expel acid anions from the cells for counteracting the toxic effects of the acids. As the pump requires energy to function optimally, high sugar levels enhance "Z. bailii" preservative resistance. Nevertheless, this view was disputed from an observation that the concentration of acid was exactly as predicted from the intracellular, extracellular pH’s and pK of the acid. Besides, it is unlikely that an active acid extrusion alone would be sufficient to achieve an unequal
Zygosaccharomyces bailii
2813999
increase the luminal surface area of the cells, presumably facilitating their resorptive function as well as putative flow sensing within the lumen. The cytoplasm of the cells is densely packed with mitochondria, which are largely found in the basal region within the infoldings of the basal plasma membrane. The high quantity of mitochondria gives the cells an acidophilic appearance. The mitochondria are needed in order to supply the energy for the active transport of sodium ions out of the cells to create a concentration gradient which allows more sodium ions to enter the cell from the luminal side. Water passively
Proximal tubule
1287549
the cell potential. The sodium-potassium pump maintains the membrane potential by moving three Na+ ions out of the cell for every two K+ ions moved into the cell. Other sources of energy for Primary active transport are redox energy and photon energy (light). An example of primary active transport using Redox energy is the mitochondrial electron transport chain that uses the reduction energy of NADH to move protons across the inner mitochondrial membrane against their concentration gradient. An example of primary active transport using light energy are the proteins involved in photosynthesis that use the energy of photons to create
Active transport
3379726
the membrane potential. Most pumps use metabolic energy (ATP) to function. For most animal cells potassium ions (K) are the most important for the resting potential. Due to the active transport of potassium ions, the concentration of potassium is higher inside cells than outside. Most cells have potassium-selective ion channel proteins that remain open all the time. There will be net movement of positively charged potassium ions through these potassium channels with a resulting accumulation of excess negative charge inside of the cell. The outward movement of positively charged potassium ions is due to random molecular motion (diffusion) and continues
Resting potential
766127
wall and membrane, killing it. As a result of not containing mitochondria, red blood cells use none of the oxygen they transport; instead they produce the energy carrier ATP by the glycolysis of glucose and lactic acid fermentation on the resulting pyruvate. Furthermore, the pentose phosphate pathway plays an important role in red blood cells; see glucose-6-phosphate dehydrogenase deficiency for more. As red blood cells contain no nucleus, protein biosynthesis is currently assumed to be absent in these cells. Because of the lack of nuclei and organelles, mature red blood cells do not contain DNA and cannot synthesize any RNA,
Red blood cell
12855643
breakdown of proteins, while reabsorption refers to the process occurring in the renal proximal tubule to reclaim amino and imino acids that have been filtered out of the blood via the glomerulus. These forms of transport require energy, as the products being transported are usually moving against a higher concentration gradient. This process, called active transport, get its energy from ATP and other ATP-related cotransport systems that produce energy, like the sodium-potassium pump. The primary defect associated with iminoglycinuria is a homozygous (recessive) mutation of the "SLC36A2" (PAT2) gene. One of several membrane transport proteins in the solute carrier family
Iminoglycinuria
4499691
Zero emission Zero emission refers to an engine, motor, process, or other energy source, that emits no waste products that pollute the environment or disrupt the climate. Vehicles and other mobile machinery used for transport (over land, sea, air, rail) and for other uses (agricultural, mobile power generation, etc.) contribute heavily to climate change and pollution, so zero emission engines are an area of active research. These technologies almost in all cases include an electric motor powered by an energy source compact enough to be installed in the vehicle. These sources include hydrogen fuel cells, batteries, supercapacitors, and flywheel energy
Zero emission
1287555
instead it relies upon the electrochemical potential difference created by pumping ions in/out of the cell. Permitting one ion or molecule to move down an electrochemical gradient, but possibly against the concentration gradient where it is more concentrated to that where it is less concentrated increases entropy and can serve as a source of energy for metabolism (e.g. in ATP synthase). The energy derived from the pumping of protons across a cell membrane is frequently used as the energy source in secondary active transport. In humans, sodium (Na) is a commonly co-transported ion across the plasma membrane, whose electrochemical gradient
Active transport
9022796
out research in both nuclear and non-nuclear energy domains, with partners from the Member States and beyond. In state-of-the-art experimental facilities, IET carries out key scientific activities in the following fields: renewable energies including solar, photovoltaics and biomass; sustainable & safe nuclear energy for current & future reactor systems; energy infrastructures and security of supply; sustainable transport, fuels and technologies including hydrogen and fuel cells as well as clean fossil fuel; energy techno/economic assessment; bioenergy including biofuels; energy efficiency in buildings, industry, transport and end-use. Institute for Energy and Transport The Institute for Energy and Transport (IET) is one of
Institute for Energy and Transport
3874104
system of DMFCs is relatively complex. The main reasons for its complexity are: Direct methanol fuel cell Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions. Efficiency is quite low for these cells, so they are targeted especially to portable applications, where energy and power density are more important than efficiency. A more efficient version of a direct fuel cell would play a key role in the theoretical use
Direct methanol fuel cell
12427070
used well away from an alternative power source, such as in alarm and communication circuits where other electric power is only intermittently available. Disposable primary cells cannot be reliably recharged, since the chemical reactions are not easily reversible and active materials may not return to their original forms. Battery manufacturers recommend against attempting to recharge primary cells. In general, these have higher energy densities than rechargeable batteries, but disposable batteries do not fare well under high-drain applications with loads under 75 ohms (75 Ω). Common types of disposable batteries include zinc–carbon batteries and alkaline batteries. Secondary batteries, also known as
Electric battery
2420849
blood flow is relatively reduced for unknown reasons, though the reduction in blood flow is not as severe as it is in ischemia. Thus cells get less glucose than they normally do, which causes an "energy crisis". Concurrently with these processes, the activity of mitochondria may be reduced, which causes cells to rely on anaerobic metabolism to produce energy, increasing levels of the byproduct lactate. For a period of minutes to days after a concussion, the brain is especially vulnerable to changes in intracranial pressure, blood flow, and anoxia. According to studies performed on animals (which are not always applicable
Concussion
1287544
the substance moved or because the substance is moved against the direction of its concentration gradient. There are two forms of active transport, primary active transport and secondary active transport. In primary active transport, the proteins involved are pumps that normally use chemical energy in the form of ATP. Secondary active transport, however, makes use of potential energy, which is usually derived through exploitation of an electrochemical gradient. The energy created from one ion moving down its electrochemical gradient is used to power the transport of another ion moving against its electrochemical gradient. This involves pore-forming proteins that form channels
Active transport
7176040
coding sequence and that is the 1 kb region known as the D-loop to which nuclear regulatory proteins bind. The number of mtDNA molecules per mitochondria varies from species to species as well as between cells with different energy demands. For example, muscle and liver cells contain more copies of mtDNA per mitochondrion than blood and skin cells do. Due to the proximity of the electron transport chain within the mitochondrial inner membrane and the production of reactive oxygen species (ROS), and due to the fact that the mtDNA molecule is not bound by or protected by histones, the mtDNA
Extrachromosomal DNA
19854511
use plasmodesmata. An intermediate type of loading exists that uses symplastic transport but utilizes a size-exclusion mechanism to ensure diffusion is a one-way process between the mesophyll and phloem cells. This process is referred to as polymer-trapping, in which simple solutes such as sucrose are synthesized into larger molecules such as stachyose or raffinose in intermediary cells. The larger molecules cannot diffuse back to the mesophyll but can move into the phloem's sieve cells. Therefore, the synthesis of larger compounds uses energy and is thus 'active' but this strategy does not require specialized proteins and can still move symplastically. Yuri
Phloem loading
6332477
properties. Motor protein Motor proteins are a class of molecular motors that can move along the cytoplasm of animal cells. They convert chemical energy into mechanical work by the hydrolysis of ATP. Flagellar rotation, however, is powered by proton pump. The best prominent example of a motor protein is the muscle protein myosin which "motors" the contraction of muscle fibers in animals. Motor proteins are the driving force behind most active transport of proteins and vesicles in the cytoplasm. Kinesins and cytoplasmic dyneins play essential roles in intracellular transport such as axonal transport and in the formation of the spindle
Motor protein
6332467
Motor protein Motor proteins are a class of molecular motors that can move along the cytoplasm of animal cells. They convert chemical energy into mechanical work by the hydrolysis of ATP. Flagellar rotation, however, is powered by proton pump. The best prominent example of a motor protein is the muscle protein myosin which "motors" the contraction of muscle fibers in animals. Motor proteins are the driving force behind most active transport of proteins and vesicles in the cytoplasm. Kinesins and cytoplasmic dyneins play essential roles in intracellular transport such as axonal transport and in the formation of the spindle apparatus
Motor protein
1698281
hypotonic filtrate is passed to the distal convoluted tubule in the renal cortex. The distal convoluted tubule has a different structure and function to that of the proximal convoluted tubule. Cells lining the tubule have numerous mitochondria to produce enough energy (ATP) for active transport to take place. Much of the ion transport taking place in the distal convoluted tubule is regulated by the endocrine system. In the presence of parathyroid hormone, the distal convoluted tubule reabsorbs more calcium and secretes more phosphate. When aldosterone is present, more sodium is reabsorbed and more potassium secreted. Atrial natriuretic peptide causes the
Nephron
20319826
researchers design new specialty optical fibers and develop new distributed fiber sensing schemes based on novel piezoelectric materials, whose shape is modified in response to an electric field, for applications as sensors for energy, safety, and structural health monitoring. Solar cells Solar cells are devices that convert the energy from sunlight to electrical current; they are therefore also called photovoltaic cells. They hold great promise as a source of renewable and clean energy and would help address the growing energy demands worldwide. PQI researchers design and fabricate solar cells consisting of various materials that exhibit exceptional transport properties that arise
Pittsburgh Quantum Institute
1287547
into the cell by the sodium-potassium pump. Active transport often takes place in the internal lining of the small intestine. Plants need to absorb mineral salts from the soil or other sources, but these salts exist in very dilute solution. Active transport enables these cells to take up salts from this dilute solution against the direction of the concentration gradient. For example, the molecules chlorine (Cl^-) and nitrate NO3- exist in the cytosol of plant cells, and need to be transported into the vacuole. While the vacuole has channels for these ions, transportation of them is against the concentration gradient,
Active transport
2761493
on its release into the cytosol - during muscle contraction. Some products of these transcriptions release H2 into the muscles. This can cause calcium ions to decay over time. In eukaryotic cells the pyruvate decarboxylation occurs inside the mitochondrial matrix, after transport of the substrate, pyruvate, from the cytosol. The transport of pyruvate into the mitochondria is via the transport protein pyruvate translocase. Pyruvate translocase transports pyruvate in a symport fashion with a proton, and hence is active, consuming energy. Upon entry to the mitochondria, the pyruvate is decarboxylated, producing acetyl-CoA. This irreversible reaction traps the acetyl-CoA within the mitochondria
Pyruvate dehydrogenase complex
15525397
nucleus. It is this ran gradient which provides the energy necessary for the transport of proteins into and out of the nucleus by karyopherin proteins. In mammalian and plant cells, RanGAP is located at the nuclear envelope during interphase. Animal RanGAP is bound to the nuclear pore component Nup358. Plant RanGAP proteins do not contain the protein domain necessary for association with Nup358 but are targeted to the nuclear rim by the plant-specific WPP domain. In contrast to plant and animal cells, yeast RanGAP is located in the cytosol. Together with RCC1 and components of the nuclear pore, RanGAP has
RanGAP
15425321
station on a place where its drawbacks are less than in other part of the park. The station will be located on the current caravan park in Arriaga park and thanks to this, fewer trees will be affected and cut down. Furthermore, the designers of the project have put some solar cells and geothermal cells to get renewable energy in order not to affect so much the environment. These cells will create 50% of all the energy needed for making everything work. Most of the residents of Lakuarriaga are against this project because it has many drawbacks, and there are
Lakuarriaga Station
4952655
an industry association representing almost 100 companies, both large and SMEs, working to promote hydrogen and fuel cells energy. The association partners with the European Commission and the research community in the public-private partnership Fuel Cells and Hydrogen Joint Undertaking (FCH JU) to accelerate the market introduction of these clean technologies in the energy and transport sectors. Chatzimarkakis wants Greece to stay in the Euro Zone. In September 2011, Vice Chancellor Philipp Rösler, wrote an article in the newspaper Die Welt, where he explained possible benefits of a Greek bankruptcy for the rest of the Eurozone. Chatzimarkakis criticized his party
Jorgo Chatzimarkakis
894125
and prostate cells sacrifice enormous amounts of energy (ATP) in order to accomplish this task. Prostate cancer cells are generally devoid of zinc. This allows prostate cancer cells to save energy not making citrate, and utilize the new abundance of energy to grow and spread. The absence of zinc is thought to occur via a silencing of the gene that produces the transporter protein ZIP1. ZIP1 is now called a tumor suppressor gene product for the gene SLC39A1. The cause of the epigenetic silencing is unknown. Strategies which transport zinc into transformed prostate cells effectively eliminate these cells in animals.
Prostate cancer
669946
are high. This occurs between meals, during fasting, starvation and strenuous exercise, when blood glucose levels are likely to fall. Fatty acids are very high energy fuels, and are taken up by all metabolizing cells that have mitochondria. This is because fatty acids can only be metabolized in the mitochondria. Red blood cells do not contain mitochondria and are therefore entirely dependent on anaerobic glycolysis for their energy requirements. In all other tissues the fatty acids that enter the metabolizing cells are combined with co-enzyme A to form acyl-CoA chains. These are transferred into the mitochondria of the cells, where
Ketone bodies
20655054
the bundle sheath cells. Different forms of CCM in phytoplankton include the active uptake of bicarbonate and CO through the cell membrane, the active transport of inorganic carbon from the cellular membrane to the chloroplasts, and active, unidirectional conversion of CO to bicarbonate. The parameters affecting C fractionation in phytoplankton contribute to "δ"C values between -18 to -25‰. Fractionation of carbon isotopes in oxygenic photosynthesis Photosynthesis converts carbon dioxide to carbohydrates via several metabolic pathways that provide energy to an organism and preferentially react with certain stable isotopes of carbon. The selective enrichment of one stable isotope over another creates
Fractionation of carbon isotopes in oxygenic photosynthesis
805736
Exocytosis Exocytosis () is a form of active transport and bulk transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell ("exo-" + "cytosis") by expelling them through an energy-dependent process. Exocytosis and its counterpart, endocytosis, are used by all cells because most chemical substances important to them are large polar molecules that cannot pass through the hydrophobic portion of the cell membrane by passive means. It is a process of which the contents of a vacuole are released, since the plant cell has large amounts of content in its vacuole, when Exocytosis is in
Exocytosis
6145860
an unequal distribution of charges across the membrane, then the difference in electric potential generates a force that drives ion diffusion until the charges are balanced on both sides of the membrane. Electrochemical potential is important in electroanalytical chemistry and industrial applications such as batteries and fuel cells. It represents one of the many interchangeable forms of potential energy through which energy may be conserved. In biological processes, the direction an ion moves by diffusion or active transport across a membrane is determined by the electrochemical gradient. In mitochondria and chloroplasts, proton gradients are used to generate a chemiosmotic potential
Electrochemical gradient
9274152
Paracellular transport Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space "between" the cells. It is in contrast to transcellular transport, where the substances travel "through" the cell, passing through both the apical membrane and basolateral membrane. The distinction has particular significance in renal physiology and intestinal physiology. Transcellular transport often involves energy expenditure whereas paracellular transport is unmediated and passive down a concentration gradient. Paracellular transport also has the benefit that absorption rate is matched to load because it has no transporters that can be saturated. In most mammals, intestinal absorption
Paracellular transport
20154645
Solid dispersion redox flow battery Solid dispersion redox flow battery is one specific type of redox flow battery using dispersed solid active materials as the energy storage media. The solid suspensions are stored in energy storage tanks and pumped through electrochemical cells while charging or discharging. In comparison with a conventional redox flow battery where active species are dissolved in aqueous or organic electrolyte, the active materials in a solid dispersion redox flow battery maintain the solid form and are suspended in the electrolyte. Further development expanded the applicable active materials. The solid active materials, especially with active materials from
Solid dispersion redox flow battery
1287556
is then used to power the active transport of a second ion or molecule against its gradient. In bacteria and small yeast cells, a commonly cotransported ion is hydrogen. Hydrogen pumps are also used to create an electrochemical gradient to carry out processes within cells such as in the electron transport chain, an important function of cellular respiration that happens in the mitochondrion of the cell. In August 1960, in Prague, Robert K. Crane presented for the first time his discovery of the sodium-glucose cotransport as the mechanism for intestinal glucose absorption. Crane's discovery of cotransport was the first ever
Active transport
8425722
tropic HIV has been noted to be able to bind to M cells and get transported across the epithelium by them. Microfold cell Microfold cells (or M cells) are found in the gut-associated lymphoid tissue (GALT) of the Peyer's patches in the small intestine, and in the mucosa-associated lymphoid tissue (MALT) of other parts of the gastrointestinal tract. These cells are known to initiate mucosal immunity responses on the apical membrane of the M cells and allow for transport of microbes and particles across the epithelial cell layer from the gut lumen to the lamina propria where interactions with immune
Microfold cell
14891684
by passing through an intercellular space between the cells. Transcellular transport Transcellular transport involves the transportation of solutes by a cell "through" a cell. One classic example is the movement of glucose from the intestinal lumen to extracellular fluid by epithelial cells. Epithelial cells use primary and secondary active transport, often in conjunction with passive diffusion through ion channels, to produce transcellular transport across epithelial tissues. This transport can either be absorption, transport from lumen (apical membrane surface) to blood, or secretion, transport from blood (basolateral membrane surface) to lumen. The transcellular pathway of transport is important in the intestinal
Transcellular transport
1287545
across the cell membrane. The difference between passive transport and active transport is that the active transport requires energy, and moves substances against their respective concentration gradient, whereas passive transport requires no energy and moves substances in the direction of their respective concentration gradient. In an antiporter, one substrate is transported in one direction across the membrane while another is cotransported in the opposite direction. In a symporter, two substrates are transported in the same direction across the membrane. Antiport and symport processes are associated with secondary active transport, meaning that one of the two substances is transported against its
Active transport
11119466
to release stored fatty acids into the blood as free fatty acids, in order to supply e.g. muscle cells with energy. In any case, also the fatty acids secreted from cells are anew taken up by other cells in the body, until entering fatty acid metabolism. The fate of cholesterol in the blood is highly determined by its constitution of lipoproteins, where some types favour transport towards body tissues and others towards the liver for excretion into the intestines. The 1987 report of National Cholesterol Education Program, Adult Treatment Panels suggest the total blood cholesterol level should be: <200 mg/dl
Blood lipids
2726981
To cause growth in the required domains, auxins must of necessity be active preferentially in them. Local auxin maxima can be formed by active biosynthesis in certain cells of tissues, for example via tryptophan-dependent pathways, but auxins are not synthesized in all cells (even if cells retain the potential ability to do so, only under specific conditions will auxin synthesis be activated in them). For that purpose, auxins have to be not only translocated toward those sites where they are needed, but also they must have an established mechanism to detect those sites. For that purpose, auxins have to be
Auxin
7484551
ion transporters are able to move ions against their concentration gradient which can then be used by secondary transporters or other proteins as a source of energy. Primary transporters use energy to transport ions such as Na , K, and Ca across a cells membrane and can create concentration gradients. This transport usually uses ATP as an energy source but can also generate ATP through methods such as the electron transport chain in plants. Transporters that use ATP convert the energy in ATP into potential energy in the form of a concentration gradient. They use the ATP to transport an
Ion transporter
17037374
goes hand in hand with investments for large-scale installations of stationary solar panels with photovoltaic cells. Similarly as other solar vehicles, many solar buses have photovoltaic cells contained in solar panels on the vehicle's roof which convert the sun's energy directly into electric energy to be used by the engine. The introduction of solar buses and other green vehicles for purposes of public transport forms a part of sustainable transport schemes. The distinction between a solar-only electric bus and an electro-solar bus is fluid, as the distinction depends on the actual usage: whether the bus is recharged from solar or
Solar bus
2815635
very similar substances. Research has correlated defects in specific carrier proteins with specific diseases. Active transport is the movement of a substance across a membrane against its concentration gradient. This is usually to accumulate high concentrations of molecules that a cell needs, such as glucose or amino acids. If the process uses chemical energy, such as adenosine triphosphate (ATP), it is called primary active transport. Secondary active transport involves the use of an electrochemical gradient, and does not use energy produced in the cell. Unlike channel proteins which only transport substances through membranes passively, carrier proteins can transport ions and
Membrane transport protein
698503
is the electronic thermal conductivity when the electrochemical potential gradient inside the sample is zero, as a starting point. As next step the transport coefficients are written as following where formula_56 and "a" the Bohr radius. The dimensionless integrals "I" are defined as where "s"("x") is the dimensionless transport distribution function. The integrals "I" are the moments of the function where "x" is the energy of carriers. By substituting the previous formulas for the transport coefficient to the equation for "λ" we get the following equation From the previous equation we see that "λ" to be zero the bracketed term
Thermal conductivity
1631440
or for starting marine diesel engines. However, because tubes/cylinders have less active material in the same volume, they also have a lower energy density than flat-plate cells. And, less active material at the electrode also means they have less material available to shed before the cell becomes unusable. Tubular/cylindrical electrodes are also more complicated to manufacture uniformly, which tends to make them more expensive than flat-plate cells. These trade-offs limit the range of applications in which tubular/cylindrical batteries are meaningful to situations where there is insufficient space to install higher capacity (and thus larger) flat-plate units. About 60% of the
Lead–acid battery
167836
chains there are amylases (named after amylose, a component of starch), cellulases (named after cellulose), chitinases (named after chitin) and more. Furthermore, for the cleavage of disaccharides, there are maltase, lactase, sucrase, trehalase and others. In humans, about 70 genes are known that code for glycosidases. They have functions in the digestion and degradation of glycogen, sphingolipids, mucopolysaccharides and poly(ADP-ribose). Humans do not produce cellulases, chitinases and trehalases, but the bacteria in the gut flora do. In order to get into or out of cell membranes of cells and membranes of cell compartments, glucose requires special transport proteins from the
Glucose
11645634
to energy are: storage, conversion, manufacturing improvements by reducing materials and process rates, energy saving (by better thermal insulation for example), and enhanced renewable energy sources. One major project that is being worked on is the development of nanotechnology in solar cells. Solar cells are more efficient as they get tinier and solar energy is a renewable resource. The price per watt of solar energy is lower than one dollar. Research is ongoing to use nanowires and other nanostructured materials with the hope of to create cheaper and more efficient solar cells than are possible with conventional planar silicon solar
Green nanotechnology
12318935
energy sources; to provide electricity to remote, far‐flung, rural and other electricity deficient areas and promote use of hydrogen as a fuel for transport and power generation; to reduce carbon emissions from energy production and consumption, to increase reliability and efficiency of electricity generation; to generate 1000 MW electricity using fuel cells by 2020 and 1 Million vehicles running on Hydrogen based IC Engines and fuel cells by 2020. National hydrogen energy road map The National Hydrogen Energy Road Map (NHERM) is a program in India initiated by the National Hydrogen Energy Board (NHEB) in 2003 and approved in 2006
National hydrogen energy road map
4229338
package the light gas by compression or liquefaction, transfer the energy carrier to the user, plus the energy lost when it is converted to useful electricity with fuel cells, leaves around 25% for practical use." Richard Gilbert, co-author of "Transport Revolutions: Moving People and Freight without Oil" (2010), comments similarly, that producing hydrogen gas ends up using some of the energy it creates. Then, energy is taken up by converting the hydrogen back into electricity within fuel cells. "'This means that only a quarter of the initially available energy reaches the electric motor' ... Such losses in conversion don't stack
Fuel cell vehicle
2341405
by storage in root cell vacuoles (3). Note that cells in the root tip do not contain vacuoles. Once in the root cell cytoplasm, Mg travels toward the centre of the root by plasmodesmata, where it is loaded into the xylem (5) for transport to the upper parts of the plant. When the Mg reaches the leaves it is unloaded from the xylem into cells (6) and again is buffered in vacuoles (7). Whether cycling of Mg into the phloem occurs via general cells in the leaf (8) or directly from xylem to phloem via transfer cells (9) is unknown.
Magnesium in biology
9231560
transport and sterol biosynthesis and regulation of oocyte gene transcription. It also provides energy substrates for oocyte meiotic resumption and promotes glycolysis. In addition, it provides protection for the oocyte. Also used in cloning procedures As a part of the process of in vitro fertilization, gene expression profiling of cumulus cells can be performed to estimate oocyte quality and the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte aneuploidy, embryo development and pregnancy outcomes. Increased knowledge in these aspects is useful in, for example, embryo selection. In gene expression profiling of cumulus cells, genes where increased expression
Cumulus oophorus
1287546
concentration gradient, utilizing the energy derived from the transport of another ion (mostly Na, K or H ions) down its concentration gradient. If substrate molecules are moving from areas of lower concentration to areas of higher concentration (i.e., in the opposite direction as, or "against" the concentration gradient), specific transmembrane carrier proteins are required. These proteins have receptors that bind to specific molecules (e.g., glucose) and transport them across the cell membrane. Because energy is required in this process, it is known as 'active' transport. Examples of active transport include the transportation of sodium out of the cell and potassium
Active transport
5280965
with companion cells, which are cells that combine with sieve tubes to create the sieve element-companion cell complex. This allows for supply and maintenance of the plant cells and for signaling between distant organs within the plant. Sieve tubes members do not have ribosomes or a nucleus and thus need companion cells to help them function as transport molecules. Companion cells provide Sieve tube members with proteins necessary for signaling and ATP in order to help them transfer molecules between different parts of the plant. It is the companion cells that helps transport carbohydrates from outside the cells into the
Sieve tube element
5009777
Photosynthetically active radiation Photosynthetically active radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be damaging to cells and tissues, but are mostly filtered out by the ozone layer in the stratosphere. Photons at longer wavelengths do not carry enough energy to allow photosynthesis to take place. Other living organisms,
Photosynthetically active radiation
15907504
of the cell, creating a vesicle containing the captured substance. Endocytosis is a pathway for internalizing solid particles ("cell eating" or phagocytosis), small molecules and ions ("cell drinking" or pinocytosis), and macromolecules. Endocytosis requires energy and is thus a form of active transport. 4. Exocytosis: Just as material can be brought into the cell by invagination and formation of a vesicle, the membrane of a vesicle can be fused with the plasma membrane, extruding its contents to the surrounding medium. This is the process of exocytosis. Exocytosis occurs in various cells to remove undigested residues of substances brought in by
Cell membrane
10041377
the synthesis of thyroid hormones. This ingested iodine is bound to serum proteins, especially to albumins. The rest of the iodine which remains unlinked and free in bloodstream, is removed from the body through urine (the kidney is essential in the removal of iodine from extracellular space). Iodine uptake is a result of an active transport mechanism mediated by the NIS protein, which is found in the basolateral membrane of thyroid follicular cells. As a result of this active transport, iodide concentration inside follicular cells of thyroid tissue is 20 to 50 times higher than in the plasma. The transport
Sodium-iodide symporter
8801595
of auxins from cells is termed "auxin efflux" and the entry of auxin in to cells is called "auxin influx". The first step in polar transport is auxin influx. Auxin enters plant cells by two methods, first by passive diffusion as non-ionized IAA molecule or the protonated form as IAAH across the phospholipid bilayer, or second by active co-transport in the anionic form IAA. As IAAH is lipophilic, it can easily cross the lipid bilayer. The inside of cells (pH ~ 7) is less acidic than the outside (the apoplast; pH ~ 5.5). So outside the cell, significant portion (17%)
Polar auxin transport
14891682
Transcellular transport Transcellular transport involves the transportation of solutes by a cell "through" a cell. One classic example is the movement of glucose from the intestinal lumen to extracellular fluid by epithelial cells. Epithelial cells use primary and secondary active transport, often in conjunction with passive diffusion through ion channels, to produce transcellular transport across epithelial tissues. This transport can either be absorption, transport from lumen (apical membrane surface) to blood, or secretion, transport from blood (basolateral membrane surface) to lumen. The transcellular pathway of transport is important in the intestinal absorption of drug molecules, the other being the paracellular
Transcellular transport
2824501
choroid plexus. CSF is formed as plasma is filtered from the blood through the epithelial cells. Choroid plexus epithelial cells actively transport sodium ions into the ventricles and water follows the resulting osmotic gradient. The choroid plexus consists of many capillaries, separated from the ventricles by choroid epithelial cells. Fluid filters through these cells from blood to become cerebrospinal fluid. There is also much active transport of substances into, and out of, the CSF as it is made. The choroid plexus mediates the production of cerebrospinal fluid (CSF). CSF acts as a medium for filtration system that facilitates the removal
Choroid plexus
19308780
in a screen for novel facilitators of transmembrane glucose transport. In this experiment, several previously uncharacterized membrane proteins were selected to be screened. These uncharacterized membrane proteins were assayed for glucose transport ability by expression in HEK293T (human embryonic kidney) cells, which have negligible glucose transport ability in the normal state. These membrane proteins were co-expressed with a fluorescent FRET (Förster resonance energy transfer) glucose sensor localized to the endoplasmic reticulum (ER). Glucose movement from the cytoplasm to the ER of the HEK293T cells was monitored by quantifying changes in FRET ratio. By using this assay, the first member of
SWEET transporters
20740452
work focused on computational and experimental fluid mechanics and heat transfer, including fundamental aspects of complex turbulence, thermosolutal transport in epitaxial crystal growth of semiconductors, and membrane separation processes for desalination and water purification. He is particularly known for his contributions to fuel cell science and technology, and for his work on sustainable energy modeling. His seminal work includes pioneering computational modeling of transport phenomena in fuel cells, and novel fuel cell architectures. His energy systems analysis work has focused on demand response methods to achieve high penetration of renewable energy in electric power systems, and the water-energy nexus. Djilali
Nedjib (Ned) Djilali
19703406
and was a true pioneer. He was both a very original thinker and a very versatile, thorough and careful experimentalist. He initiated a revolution in our understanding of ion transport in plant cells. His demonstration (in 1972) that the most important transport system in the plasmalemma of Characean cells is a proton-pumping ATPase, generating membrane potentials well negative of the potassium equilibrium potential, was a major advance… Previously plant physiologists had assumed that plant cells were like animal cells, with an ATP-dependent sodium-potassium exchange pump as the major process of active ion transport. There was opposition to this new view,
Roger M. Spanswick
1536371
cells. All mammals have four different sodium pump sub-types, or isoforms. Each has unique properties and tissue expression patterns. The -ATPase helps maintain resting potential, affects transport, and regulates cellular volume. It also functions as a signal transducer/integrator to regulate the MAPK pathway, ROS, as well as intracellular calcium. In most animal cells, the -ATPase is responsible for about 1/4 of the cell's energy expenditure. For neurons, the -ATPase can be responsible for up to 3/4 of the cell's energy expenditure. In order to maintain the cell membrane potential, cells keep a low concentration of sodium ions and high levels
Na+/K+-ATPase
14973472
often energy and space intensive, it is often more convenient to use the chemicals directly in the fuel cell. Direct Methanol Fuel Cells (DMFC's), for example, use methanol as the reactant instead of first using reformation to produce hydrogen. Although DMFC's are not very efficient (~25%), they are energy dense which means that they are quite suitable for portable power applications. Another advantage over gaseous fuels, as in the H-O cells, is that liquids are much easier to handle, transport, pump and often have higher specific energies allowing for greater power extraction. Generally gases need to be stored in high
Membraneless Fuel Cells
894124
metastasizes to the bones, lymph nodes, and may invade rectum, bladder and lower ureters after local progression. The route of metastasis to bone is thought to be venous as the prostatic venous plexus draining the prostate connects with the vertebral veins. The prostate is a zinc-accumulating, citrate-producing organ. The protein ZIP1 is responsible for the active transport of zinc into prostate cells. One of the zinc's important roles is to change the metabolism of the cell in order to produce citrate, an important component of semen. The process of zinc accumulation, alteration of metabolism, and citrate production is energy inefficient,
Prostate cancer
14958557
of bacteria. It is known that electric fields can influence cell membranes from studies on electroporation. Electric fields on the cells being treated by a plasma jet can be high enough to produce electroporation, which may directly influence the cell behavior, or may simply allow more reactive species to enter the cell. Both physical and chemical properties of plasma are known to induce uptake of nanomaterials in cells. For example, the uptake of 20 nm gold nanoparticles can be stimulated in cancer cells using non-lethal doses of cold plasma. Uptake mechanisms involve both energy dependent endocytosis and energy independent transport
Plasma medicine
2900581
usually formed from assemblages of protein molecules. Ion channels provide passageways through which ions can move. In most cases, an ion channel is permeable only to specific types of ions (for example, sodium and potassium but not chloride or calcium), and sometimes the permeability varies depending on the direction of ion movement. Ion pumps, also known as ion transporters or carrier proteins, actively transport specific types of ions from one side of the membrane to the other, sometimes using energy derived from metabolic processes to do so. Ion pumps are integral membrane proteins that carry out active transport, i.e., use
Membrane potential
278159
secrete these enzymes from specialized cells in their guts, including the stomach and pancreas, and salivary glands. The amino acids or sugars released by these extracellular enzymes are then pumped into cells by active transport proteins. Carbohydrate catabolism is the breakdown of carbohydrates into smaller units. Carbohydrates are usually taken into cells once they have been digested into monosaccharides. Once inside, the major route of breakdown is glycolysis, where sugars such as glucose and fructose are converted into pyruvate and some ATP is generated. Pyruvate is an intermediate in several metabolic pathways, but the majority is converted to acetyl-CoA through
Metabolism
790149
a3 group can no longer do so. Instead, these electrons destabilize the compound; thus, the heme group no longer accept them. Consequently, electron transport is halted, and cells can no longer produce the energy needed to synthesize ATP. In a human weighing , death occurs within two minutes of inhaling 70 mg of hydrogen cyanide. Hydrogen cyanide, discovered in the late 18th century, was used in the 1880s for the fumigation of citrus trees in California. Its use spread to other countries for the fumigation of silos, goods wagons, ships, and mills. Its light weight and rapid dispersal meant its
Zyklon B
8174267
the thymus, pre-T cells undergo a selection process where they must be positively selected and should avoid negative selection. B cells that bind with low avidity to self-MHC receptors are positively selected for maturation, those that do not die by apoptosis. Cells that survive positive selection, but bind strongly to self-antigens are negatively selected also by active induction of apoptosis. This negative selection is known as clonal deletion, one of the mechanisms for B cell tolerance. Approximately 99 percent of pre-B cells within the thymus are negatively selected. Only approximately 1 percent are positively selected for maturity. However, there is
Molecular mimicry
3856302
ordinary matter) per unit mass. Outside the core of the star, where nuclear reactions occur, no energy is generated, so the luminosity is constant. The energy transport equation takes differing forms depending upon the mode of energy transport. For conductive energy transport (appropriate for a white dwarf), the energy equation is where "k" is the thermal conductivity. In the case of radiative energy transport, appropriate for the inner portion of a solar mass main sequence star and the outer envelope of a massive main sequence star, where formula_20 is the opacity of the matter, formula_21 is the Stefan-Boltzmann constant, and
Stellar structure
7946222
cost to the vehicle powertrain. Direct methanol fuel cells do not require a reformer, but provide a lower energy density compared to conventional fuel cells, although this could be counterbalanced with the much better energy densities of ethanol and methanol over hydrogen. Alcohol fuel is a renewable resource. Solid-oxide fuel cells can operate on light hydrocarbons such as propane and methane without a reformer, or can run on higher hydrocarbons with only partial reforming, but the high temperature and slow startup time of these fuel cells are problematic for automotive applications. Aluminum has been proposed as an energy storage method
Hydrogen storage
4504316
PEP group translocation PEP group translocation, also known as the phosphotransferase system or PTS, is a distinct method used by bacteria for sugar uptake where the source of energy is from phosphoenolpyruvate (PEP). It is known as multicomponent system that always involves enzymes of the plasma membrane and those in the cytoplasm. The PTS system uses active transport. After the translocation across the membrane, the metabolites transported are modified. The system was discovered by Saul Roseman in 1964. The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) transports and phosphorylates its sugar substrates in a single energy-coupled step. This transport process is dependent
PEP group translocation
15305199
Sodium-ion battery Sodium-ion batteries (SIB) are a type of rechargeable metal-ion battery that uses sodium ions as charge carriers. Battery-grade salts of sodium are cheap and abundant, much more so than those of lithium. This makes them a cost-effective alternative especially for applications where weight and energy density are of minor importance such as grid energy storage for renewable energy sources such as wind- and solar power These cells can be completely drained (to zero charge) without damaging the active materials. They can be stored and shipped safely. Lithium-ion batteries must retain about 30% of charge during storage, enough that
Sodium-ion battery
15170521
sudden break of the cooling circuit. In 1989 Andriesse was appointed professor of electricity supply at the University of Utrecht. This position was paid by KEMA. Commotion arose, when he expressed opinions about the safety of nuclear power plants, which were too negative in the eyes of KEMA. Eventually the conflict was resolved by Andriesse moving to a position financed by the University of Utrecht. As professor of energy physics, he investigated why photovoltaic cells are more efficient in using solar energy than plants. Molecular transport in plant cells turned out to be the limiting factor. For the Energy Research
Cornelis Dirk Andriesse
4135242
will remain active for the duration of the learned sequence, even if the remainder of the cortical column is shifting state. Since we do not know the encoding of the sequence, we do not yet know the definition of "ON" or "active"; Hawkins suggests that the ON pattern may be as simple as a simultaneous AND (i.e., the name cells simultaneously "light up") across an array of name cells. 6. Hawkins' novel prediction is that certain cells are inhibited during a learned sequence. A class of cells in layers 2 and 3 should NOT fire during a learned sequence, the
On Intelligence
18080555
California. Oorja has been advocate of methanol economy. The company was funded by Sequoia Capital, Dag Ventures, Artis Capital Management, McKenna Ventures Management, and Mingxin China Growth Fund. Oorja Fuel Cells is working with market leaders around the world such as Toyota Tsusho, Baldor, and US Foods. Oorja has partnered with Toyota Tsusho in pursuit of wide commercial adoption of affordable fuel cells to help solve energy and transportation challenges in Japan. As methanol fuel cells cost less than hydrogen batteries because methanol is easier to transport and handle than hydrogen, this will hope to cut down on energy costs
Oorja Fuel Cells
15595644
applications the active compound must carry out the reaction. This allows for maximum efficacy of the active drug. Also, the use of nanoparticles results in the attraction of proteins to the surfaces of cells, giving cell membranes a biological identity. They also use endogenous active transport where transferrin, an iron binding protein, is linked to rod-shaped semiconductor nanocrystals, in order to move across the BBB into the brain. This discovery is a promising development towards designing an efficient nanoparticle-based drug delivery system. Nanoparticle–biomolecule conjugate A nanoparticle–biomolecule conjugate is a nanoparticle with biomolecules attached to its surface. Nanoparticles are minuscule particles,
Nanoparticle–biomolecule conjugate
6614125
energy as ATP from a multi-step process known as cellular respiration, more specifically from oxidative phosphorylation at the mitochondrial cristae. Iron is present in the iron-sulfur clusters and heme groups of the electron transport chain proteins that generate a proton gradient that allows ATP synthase to synthesize ATP (chemiosmosis). Heme groups are part of hemoglobin, a protein found in red blood cells that serves to transport oxygen from the lungs to the tissues. Heme groups are also present in myoglobin to store and diffuse oxygen in muscle cells. The human body needs iron for oxygen transport. Oxygen (O) is required
Human iron metabolism
588396
addition to carrying oxygen, blood also carries hormones, waste products and nutrients for cells of the body. Blood vessels do not actively engage in the transport of blood (they have no appreciable peristalsis). Blood is propelled through arteries and arterioles through pressure generated by the heartbeat. Blood vessels also transport red blood cells which contain the oxygen necessary for daily activities. The amount of red blood cells present in your vessels has an effect on your health. Hematocrit tests can be performed to calculate the proportion of red blood cells in your blood. Higher proportions result in conditions such as
Blood vessel
5376966
is located in the apical membrane of the renal tubular cells, where it plays a role in tubular reabsorption. The defective OCTN2 is unable to recapture carnitine prior to its excretion in urine, leading to the characteristic biochemical findings of massively increased urine carnitine levels and significantly decreased plasma carnitine levels. Decreased levels of plasma carnitine inhibit fatty acid oxidation during times of excessive energy demand. Carnitine is needed to transport long chain fatty acids into the mitochondria, where they can be broken down to produce acetyl-CoA. Individuals with SPCD cannot produce ketone bodies as energy due to the interruption
Systemic primary carnitine deficiency
109258
Chemical potential) an energy flow will occur from S to S, because nature always prefers low energy and maximum entropy. Molecular diffusion is typically described mathematically using Fick's laws of diffusion. Diffusion is of fundamental importance in many disciplines of physics, chemistry, and biology. Some example applications of diffusion: Diffusion is part of the transport phenomena. Of mass transport mechanisms, molecular diffusion is known as a slower one. In cell biology, diffusion is a main form of transport for necessary materials such as amino acids within cells. Diffusion of solvents, such as water, through a semipermeable membrane is classified as
Molecular diffusion
1287542
of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants. In 1848, the German physiologist Emil du Bois-Reymond suggested the possibility of active transport of substances across membranes. Rosenberg (1948) formulated the concept of active transport based on energetic considerations, but later it would be redefined. In 1997, Jens Christian Skou, a Danish physician received the Nobel Prize in Chemistry for his research regarding the sodium-potassium pump One category of cotransporters that is especially prominent in research regarding diabetes treatment is sodium glucose cotransporters. These transporters were discovered by scientists at
Active transport
4667399
membranes by the addition of highly acidic or basic functional groups, e.g. sulfonic acid and quaternary ammonium, enabling the membrane to form water channels and selectively transport cations or anions, respectively. The most important functional materials in this category include proton exchange membranes and alkaline anion exchange membranes, that are at the heart of many technologies in water treatment, energy storage, energy generation. Applications within water treatment include reverse osmosis, electrodialysis, and reversed electrodialysis. Applications within energy storage include rechargeable metal-air electrochemical cells and various types of flow battery. Applications within energy generation include proton exchange membrane fuel cells (PEMFCs),
Synthetic membrane
1287548
and thus movement of these ions is driven by hydrogen pumps, or proton pumps Primary active transport, also called direct active transport, directly uses metabolic energy to transport molecules across a membrane. Substances that are transported across the cell membrane by primary active transport include metal ions, such as Na, K, Mg, and Ca. These charged particles require ion pumps or ion channels to cross membranes and distribute through the body. Most of the enzymes that perform this type of transport are transmembrane ATPases. A primary ATPase universal to all animal life is the sodium-potassium pump, which helps to maintain
Active transport
12053783
Calcium pump Calcium pumps are a family of ion transporters found in the cell membrane of all animal cells. They are responsible for the active transport of calcium out of the cell for the maintenance of the steep Ca electrochemical gradient across the cell membrane. Calcium pumps play a crucial role in proper cell signalling by keeping the intracellular calcium concentration roughly 10,000 times lower than the extracellular concentration. Failure to do so is one cause of muscle cramps. The plasma membrane Ca ATPase and the sodium-calcium exchanger are together the main regulators of intracellular Ca concentrations. Ca has many
Calcium pump
7079573
to be part of our energy solution... We get about 20% of our energy from nuclear power in our country... other countries like France get much much more, so we do have to look at it because it doesn't put greenhouse gas emissions into the air." Subsequently, in a July 2007 Democratic debate, when asked about nuclear power as an alternative energy source, she said, "I'm agnostic about nuclear power. Until we figure out what we're going to do with the waste and the cost, it's very hard to see nuclear as a part of our future. But that's where
Political positions of Hillary Clinton
304638
ATP. In eukaryotes, these redox reactions are carried out by a series of protein complexes within the inner membrane of the cell's mitochondria, whereas, in prokaryotes, these proteins are located in the cells' intermembrane space. These linked sets of proteins are called electron transport chains. In eukaryotes, five main protein complexes are involved, whereas in prokaryotes many different enzymes are present, using a variety of electron donors and acceptors. The energy released by electrons flowing through this electron transport chain is used to transport protons across the inner mitochondrial membrane, in a process called "electron transport". This generates potential energy
Oxidative phosphorylation
8801592
Polar auxin transport Polar auxin transport is the regulated transport of the plant hormone auxin in plants. It is an active process, the hormone is transported in cell-to-cell manner and one of the main features of the transport is its directionality (polarity). The polar auxin transport has coordinative function in plant development, the following spatial auxin distribution underpins most of plant growth responses to its environment and plant growth and developmental changes in general. Polar auxin transport (PAT) is directional and active flow of auxin molecules through the plant tissues. The flow of auxin molecules through the neighboring cells is
Polar auxin transport
1722766
PS I for photosynthesis. Thousands of bacteriochlorophyll(BCHl) c, d and e of the cells absorb light at 720-750 nm, and the light energy is transferred to BChl a-795 and a-808 before being transferred to Fenna-Matthews-Olson (FMO)-proteins which are connected to reaction centers (RC). The FMO complex then transfers the excitation energy to the RC with its special pair which absorbs at 840 nm in the plasma membrane. After the reaction centers receive the energy, electrons are ejected and transferred through electron transport chains (ETCs). Some electrons form Fe-S proteins in electron transport chains are accepted by ferredoxins (Fd) which can
Green sulfur bacteria