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Symporter
A symporter is an integral membrane protein that is involved in the transport of two (or more) different molecules across the cell membrane in the same direction. The symporter works in the plasma membrane and molecules are transported across the cell membrane at the same time, and is, therefore, a type of cotransporter. The transporter is called a symporter, because the molecules will travel in the same direction in relation to each other. This is in contrast to the antiport transporter. Typically, the ion(s) will move down the electrochemical gradient, allowing the other molecule(s) to move against the concentration gradient. The movement of the ion(s) across the membrane is facilitated diffusion, and is coupled with the active transport of the molecule(s). In symport, two molecule move in 'similar direction' at the 'same time' Example of symport:- movement of glucose along with sodium ion Examples SGLT1 in the intestinal epithelium transports sodium ions (Na+) and glucose acro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotransporter
Cotransporters are a subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient. They enable active transport#Secondary active transport, coupled or cotransport (secondary active transport) and include antiporters and symporters. In general, cotransporters consist of two out of the three classes of integral membrane proteins known as transporters that move molecules and ions across biomembranes. Uniporters are also transporters but move only one type of molecule down its concentration gradient and are not classified as cotransporters. Background Cotransporters are capable of moving solutes either up or down gradients at rates of 1000 to 100000 molecules per second. They may act as channels or transporters, depending on conditions under which they are assayed. The movement occurs by binding to two molecules or ions at a ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cotransporter
Cotransporters are a subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient. They enable active transport#Secondary active transport, coupled or cotransport (secondary active transport) and include antiporters and symporters. In general, cotransporters consist of two out of the three classes of integral membrane proteins known as transporters that move molecules and ions across biomembranes. Uniporters are also transporters but move only one type of molecule down its concentration gradient and are not classified as cotransporters. Background Cotransporters are capable of moving solutes either up or down gradients at rates of 1000 to 100000 molecules per second. They may act as channels or transporters, depending on conditions under which they are assayed. The movement occurs by binding to two molecules or ions at a ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Transport
In cellular biology, ''active transport'' is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of 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 adenosine triphosphate ( ATP), and secondary active transport that uses an electrochemical gradient. Some examples of active transport include: * Phagocytosis of bacteria by macrophages * Movement of calcium ions out of cardiac muscle cells * Transportation of amino acids across the intestinal lining in the human gut * Secretion of proteins such as enzymes, peptide hormones, and antibodies from various cells * Functioning of white blood cells to defend invading diseases Active cellular transportation (ACT) Unlike passive transport, which uses the kinetic energy and natural entropy of molecules moving down a gradient, activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-transport
In cellular biology, ''active transport'' is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of 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 adenosine triphosphate ( ATP), and secondary active transport that uses an electrochemical gradient. Some examples of active transport include: * Phagocytosis of bacteria by macrophages * Movement of calcium ions out of cardiac muscle cells * Transportation of amino acids across the intestinal lining in the human gut * Secretion of proteins such as enzymes, peptide hormones, and antibodies from various cells * Functioning of white blood cells to defend invading diseases Active cellular transportation (ACT) Unlike passive transport, which uses the kinetic energy and natural entropy of molecules moving down a gradient, active ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loop Diuretics
Loop diuretics are diuretics that act on the Na-K-Cl cotransporter along the thick ascending limb of the loop of Henle in the kidney. They are primarily used in medicine to treat hypertension and edema often due to congestive heart failure or chronic kidney disease. While thiazide diuretics are more effective in patients with normal kidney function, loop diuretics are more effective in patients with impaired kidney function. Mechanism of action Loop diuretics are 90% bonded to proteins and are secreted into the proximal convoluted tubule through organic anion transporter 1 (OAT-1), OAT-2, and ABCC4. Loop diuretics act on the Na+-K+-2Cl− symporter (NKCC2) in the thick ascending limb of the loop of Henle to inhibit sodium, chloride and potassium reabsorption. This is achieved by competing for the Cl− binding site. Loop diuretics also inhibits NKCC2 at macula densa, reducing sodium transported into macula densa cells. This stimulates the release of renin, which through reni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loop Of Henle
In the kidney, the loop of Henle () (or Henle's loop, Henle loop, nephron loop or its Latin counterpart ''ansa nephroni'') is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer, the German anatomist Friedrich Gustav Jakob Henle, the loop of Henle's main function is to create a concentration gradient in the medulla of the kidney. By means of a countercurrent multiplier system, which uses electrolyte pumps, the loop of Henle creates an area of high urea concentration deep in the medulla, near the papillary duct in the collecting duct system. Water present in the filtrate in the papillary duct flows through aquaporin channels out of the duct, moving passively down its concentration gradient. This process reabsorbs water and creates a concentrated urine for excretion. Structure The loop of Henle can be divided into four parts: *Thin descending limb of loop of Henle :The thin descending limb has low per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Rehydration Therapy
Oral rehydration therapy (ORT) is a type of fluid replacement used to prevent and treat dehydration, especially due to diarrhea. It involves drinking water with modest amounts of sugar and salts, specifically sodium and potassium. Oral rehydration therapy can also be given by a nasogastric tube. Therapy should routinely include the use of zinc supplements. Use of oral rehydration therapy has been estimated to decrease the risk of death from diarrhea by up to 93%. Side effects may include vomiting, high blood sodium, or high blood potassium. If vomiting occurs, it is recommended that use be paused for 10 minutes and then gradually restarted. The recommended formulation includes sodium chloride, sodium citrate, potassium chloride, and glucose. Glucose may be replaced by sucrose and sodium citrate may be replaced by sodium bicarbonate, if not available. It works as glucose increases the uptake of sodium and thus water by the intestines. A number of other formulations are also a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Na-K-2Cl Symporter
The Na-K-Cl cotransporter (NKCC) is a protein that aids in the secondary active transport of sodium, potassium, and chloride into cells. In humans there are two isoforms of this membrane transport protein, NKCC1 and NKCC2, encoded by two different genes (''SLC12A2'' and ''SLC12A1'' respectively). Two isoforms of the NKCC1/Slc12a2 gene result from keeping (isoform 1) or skipping (isoform 2) exon 21 in the final gene product. NKCC1 is widely distributed throughout the human body; it has important functions in organs that secrete fluids. It is found specifically in the kidney, where it extracts sodium, potassium, and chloride from the urine so they can be reabsorbed into the blood. Function NKCC proteins are membrane transport proteins that transport sodium (Na), potassium (K), and chloride (Cl) ions across the cell membrane. Because they move each solute in the same direction, they are considered symporters. They maintain electroneutrality by moving two positively charged solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facilitated Diffusion
Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins. Being passive, facilitated transport does not directly require chemical energy from ATP hydrolysis in the transport step itself; rather, molecules and ions move down their concentration gradient reflecting its diffusive nature. Facilitated diffusion differs from simple diffusion in several ways. # the transport relies on molecular binding between the cargo and the membrane-embedded channel or carrier protein. # the rate of facilitated diffusion is saturable with respect to the concentration difference between the two phases; unlike free diffusion which is linear in the concentration difference. # the temperature dependence of facilitated transport is substantially different due to the presence of an activated bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium-glucose Transport Proteins
Sodium-dependent glucose cotransporters (or sodium-glucose linked transporter, SGLT) are a family of glucose transporter found in the intestinal mucosa (enterocytes) of the small intestine (SGLT1) and the proximal tubule of the nephron ( SGLT2 in PCT and SGLT1 in PST). They contribute to renal glucose reabsorption. In the kidneys, 100% of the filtered glucose in the glomerulus has to be reabsorbed along the nephron (98% in PCT, via SGLT2). If the plasma glucose concentration is too high (hyperglycemia), glucose passes into the urine ( glucosuria) because SGLT are saturated with the filtered glucose. Types The two most well known members of SGLT family are SGLT1 and SGLT2, which are members of the SLC5A gene family. In addition to SGLT1 and SGLT2, there are 10 other members in the human protein family SLC5A. Of these, SLC5A4/SGLT3 (SAAT1) is a low-affinity transporter for glucose, but seems to have more of an electric function. The other SLC5 proteins transport mannose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uniporter
A uniporter is a membrane transport protein that transports a single species of substrate ( charged or uncharged) across a cell membrane. It may use either facilitated diffusion and transport along a diffusion gradient or transport against one with an active transport process. Uniporters include both carriers and ion channels, and are referred to as facilitated transporters, suggesting movement down a concentration or electrochemical gradient. Uniporter carrier proteins work by binding to one molecule of substrate at a time. Uniporter channels open in response to a stimulus and allow the free flow of specific molecules. There are several ways in which the opening of uniporter channels may be regulated: # Voltage – Regulated by the difference in voltage across the membrane # Stress – Regulated by physical pressure on the transporter (as in the cochlea of the ear) # Ligand – Regulated by the binding of a ligand to either the intracellular or extracellular side of the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiporter
An antiporter (also called exchanger or counter-transporter) is a cotransporter and integral membrane protein involved in secondary active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in opposite directions, one into the cell and one out of the cell. Na+/H+ antiporters have been reviewed. In secondary active transport, one species of solute moves along its electrochemical gradient, allowing a different species to move against its own electrochemical gradient. This movement is in contrast to primary active transport, in which all solutes are moved against their concentration gradients, fueled by ATP. Transport may involve one or more of each type of solute. For example, the Na+/Ca2+ exchanger, found in the plasma membrane of many cells, moves three sodium ions in one direction, and one calcium ion in the other. Role in Homeostatic Mechanisms Na+/H+ Antiporters Antiporters, such as Na+/H+ antiporter protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
