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Gradient in Biological Definition

Ion gradient

... An ion gradient is a concentration gradient of ions , it can be called an electrochemical potential gradient of ions across membranes. Ionophores are ...

Diffusion

... or electrical conductivity) multiplied by a gradient (concentration gradient or thermal gradient or electric field). The generic diffusion ...

Gradient

... In vector calculus , the gradient of a scalar field is a vector field which ... representing higher values, and its corresponding gradient is represented by blue arrows. More rigorously, the gradient of a function from the Euclidean space R n ...

Passive transport

... two areas is often termed as the concentration gradient , and diffusion will continue until this gradient has been eliminated. Since diffusion moves ... gradient"). If and when the concentration gradient have been eliminated, no net exchange of material ...

Active transport

... transport, molecules move against either an electrical or concentration gradient (collectively termed an electrochemical gradient ). This is achieved by either altering the affinity of the binding site or ...

Apoptosis

... structures called the notochord and the floor plate secrete a gradient of the signaling molecule Sonic hedgehog (Shh), and it is this gradient that directs cells to form patterns in the embryonic neural tube: cells ...

Morphogenesis

... the maternal effect genes are translated into proteins a Bicoid protein gradient forms at the anterior end of the egg. Nanos protein forms a gradient at the posterior end. The Bicoid protein blocks translation of caudal ...

Mitochondrion

... the transfer use the released energy to pump protons (H + ) against a gradient (the concentration of protons in the intermembrane space is higher than ... concentration increases in the intermembrane space, a strong diffusion gradient is built up. The only exit for these protons is through the ATP ...

Mitochondrion

... the transfer use the released energy to pump protons (H + ) against a gradient (the concentration of protons in the intermembrane space is higher than ... concentration increases in the intermembrane space, a strong diffusion gradient is built up. The only exit for these protons is through the ATP ...

Morphogenesis

... the maternal effect genes are translated into proteins a Bicoid protein gradient forms at the anterior end of the egg. Nanos protein forms a gradient at the posterior end. The Bicoid protein blocks translation of caudal ...

Magnetic resonance imaging

... relaxation information. For this reason, magnetic fields with an intensity gradient are applied in addition to the strong alignment field to allow encoding of the position of the nuclei. A field with the gradient increasing in each of the three dimensional planes is applied in sequence. ...

Operator

... and vector fields Main articles: vector calculus , scalar field , gradient , divergence , and curl Three main operators are key to vector calculus , the operator ∇, known as gradient , where at a certain point in a scalar field forms a vector which points ...

ATP synthase

... Physiological role The F 1 F O ATP synthase is a reversible enzyme. Large enough quantities of ATP cause it to create a transmembrane proton gradient , this is used by fermenting bacteria which do not have an electron transport chain, and hydrolyze ATP to make a proton gradient, which they use for ...

ATPase

... ATP synthetase (or ATP synthase ) of mitochondria and chloroplasts is an anabolic enzyme that harnesses the energy of a transmembrane proton gradient as an energy source for adding an inorganic phosphate group to a molecule of adenosine diphosphate (ADP) to form a molecule of adenosine ...

Biology

... is that there are so many different possible interactions with other organisms and the environment. A microscopic bacterium responding to a local gradient in sugar is as much responding to its environment as a lion is responding to its environment when it is searching for food in the African ...

Biomechanics

... components. Commonly used second order tensors include the Cauchy stress tensor, the second Piola-Kirchhoff stress tensor, the deformation gradient tensor, and the Green strain tensor. A reader of the biomechanics literature would be well-advised to note precisely the definitions of the various ...

Chemiosmotic hypothesis

... Mitchell, that the mitochondrion functioned as a kind of electrochemical capacitor , using the energy of NADH and FADH 2 to create a proton gradient across the mitochondrial membrane and that this energy was used by a reversible proton pump , the ATP synthase , to create ATP . This was a ...

Chromatography

... Solvents used include any miscible combination of water or various organic liquids (the most common are methanol or acetonitrile ). Often, a gradient over time in the solvent composition passing through the column is used to separate analyte mixtures, as a function of how well the changing solvent ...

Cytosol

... internal movement of structures, e.g., transport vesicles . As the concentration of soluble molecules increases within the cytosol, an osmotic gradient builds up toward the outside of the cell. Water flows into the cell, making the cell larger. To prevent the cell from bursting apart, molecular pumps ...

Flagellum

... powered by proton motive force , i.e., by the flow of protons (i.e., hydrogen ions ) across the bacterial cell membrane due to a concentration gradient set up by the cell's metabolism (in Vibrio species the motor is a sodium ion pump, rather than a proton pump ). The rotor transports protons ...

Cell membrane

... transport, this process does not involve chemical energy ( ATP ). Active transport Typically moves molecules against their electrochemical gradient , a process that would be entropically unfavorable were it not stoichiometrically coupled with the hydrolysis of ATP. This coupling can be either ...

Intermembrane space

... . These are known as TOM and TIM in mitochondria and TOC and TIC in chloroplasts . It tends to have a low pH because of the proton gradient which results when protons are pumped from the mitochondrial matrix into the intermembrane space during electron transport . The structures ...

Kidney

... . The loop of Henle was named after Friedrich Gustav Jakob Henle who described it in the early 1860s. The loop of Henle maintains an osmotic gradient set up as a countercurrent exchange to filter and concentrate glomerular filtrate. Cells lining the tubule have numerous mitochondria , enabling ...

Light-dependent reaction

... returning to chlorophyll. This transport chain produces a proton-motive force, pumping H + ions across the membrane; this produces a concentration gradient which can be used to power ATP synthase . This pathway is known as cyclic photophosphorylation, and it produces neither O 2 nor NADPH. ...

Redox

... the reduced carbon compounds are used to reduce Nicotinamide adenine dinucleotide (NAD + ), which then contributes to the creation of a proton gradient , which drives the synthesis of Adenosine triphosphate (ATP) and is maintained by the reduction of oxygen. In animal cells, mitochondria ...

Oxidative phosphorylation

... mechanism (involving NADH-Q reductase , cytochrome c oxidase , and cytochrome reductase ) to pump H + across the membrane against a proton gradient . A large protein complex called ATP synthase is embedded in that membrane and enables protons to pass through in both directions; it generates ...

Light-dependent reaction

... returning to chlorophyll. This transport chain produces a proton-motive force, pumping H + ions across the membrane; this produces a concentration gradient which can be used to power ATP synthase . This pathway is known as cyclic photophosphorylation, and it produces neither O 2 nor NADPH. ...

Cell membrane

... transport, this process does not involve chemical energy ( ATP ). Active transport Typically moves molecules against their electrochemical gradient , a process that would be entropically unfavorable were it not stoichiometrically coupled with the hydrolysis of ATP. This coupling can be either ...

Potential energy

... it is possible to define a numerical value of potential associated with every point in space. A force field can be re-obtained by taking the vector gradient of the potential field. For example, gravity is a conservative force . The work done by a unit mass going from point A with U = a to point ...

Proton-motive force

... process involves the Proton-motive force in some step. This can be described as the storing of energy as a combination of a proton and voltage gradient across a plasma membrane . In eukaryotes the Proton-motive force exists across the inner mithochondrial membrane. It is generated by energy from ...

Proton pump

... capable of moving protons across the membrane of a cell , mitochondrion , or other subcellular compartment, thereby creating a difference or gradient in both pH and electrical charge (ignoring differences in buffer capacity ) and tending to establish an electrochemical potential . In ...

Redox

... the reduced carbon compounds are used to reduce Nicotinamide adenine dinucleotide (NAD + ), which then contributes to the creation of a proton gradient , which drives the synthesis of Adenosine triphosphate (ATP) and is maintained by the reduction of oxygen. In animal cells, mitochondria ...
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