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flow in Biological Definition

Evolution

... drift or changes in population structure ( gene flow ). Contents showTocToggle("show","hide") ... selection 1.3.2 Genetic drift 1.3.3 Gene flow 1.4 Microevolution and macroevolution ... of an allele: Genetic drift Gene flow Natural selection Natural selection ...

Flagellum

... is powered by proton motive force , i.e., by the flow of protons (i.e., hydrogen ions ) across the ... include: Bacterial flagella are powered by a flow of H + ions (or occasionally Na + ions); ... "tube" inside that the flagellin subunits can flow up the inside of the filament and get added at ...

Lung

... lungs, accompanied by air sacs to control the flow of gas through it. See Bird#Respiration for a ... air sacs (typically nine) which control air flow through the lungs, but do not play a direct role in gas exchange. They have a flow through respiration system. When a bird ...

Species

... interbreeding and the actual likelihood of gene flow between populations. For example, it is possible ... develop, and given reproductive isolation, gene flow between the populations cannot merge the ... often behavioral, that is preventing gene flow between the populations, and therefore that they ...

Xylem

... remains, forming a nonliving passage for the flow of water. Vessel elements form in plant parts ... vessel elements are perforated, enabling water to flow through vessels. Xylem cells are also known as ... the roots to the leaves . It travels by bulk flow , like water in a series of pipes, rather than by ...

Active transport

... opposite directions across a membrane. One of these species is allowed to flow from high to low concentration, which yields the entropic energy to ... intermittent needs. Co-transport Co-transport also uses the flow of one solute species from high to low concentration to move another ...

Dialysis

... twist valve located in the tip of their catheter; this permits fluid to flow into or out of the peritoneal cavity. Because the full bag of fluid is ... (UK: haemodialysis) is somewhat different. It works by having the blood flow along one side of a semipermeable membrane , with the dialysis solution ...

Diffusion

... and the electric field. Momentum diffusion In the case of laminar flow of a liquid flowing past a solid surface, momentum diffuses across the ... circulation Isotope separation Kirkendall effect Laminar flow Liposomes List of biochemistry topics List of biology ...

Electrophysiology

... is the science and branch of physiology that pertains to the flow of ions in biological tissues and, in particular, to the electrical recording techniques that enable the measurement of this flow and the potential changes related to them. At the cellular level, these ...

Ion channel

... that surround all biological cells . By conducting and controlling the flow of ions , these pore -forming proteins help establish the small ... receptor Inward-rectifier K channels allow potassium to flow into the cell in an inwardly rectifying manner. They are involved in ...

Natural selection

... humans . Other mechanisms of evolution include genetic drift and gene flow . Mutations create the genetic variation on which natural selection ... reproduction (which mixes the DNA of two parents into an offspring), gene flow and genetic drift are also important mechanisms. Competition ...

Thermoregulation

... perspiration. Dilatation of the cutaneous vascular areas leads to a larger flow of blood through the skin, and so tends to cool the body, and vice versa. ... metabolism have reduced extremities some have countercurrent blood flow in extremities (e.g. timber wolves) to avoid freezing of tissues. In ...

Trait

... of molecular biology as stated by Francis Crick . This information flow may also be followed through the Cell as it travels from the DNA in ... thus go on to generate different traits through the information flow charted above. For example, if the alleles on homologous chromosomes ...

Alternative splicing

... polypeptide is produced, given a DNA sequence and pre-mRNA. (This does not necessarily negate the central dogma of genetics which is about the flow of information from genes to proteins). Since the ways of regulation are inherited, the interpretation of a mutation may be changed. It has been ...

Anton van Leeuwenhoek

... of cell biology . Using his handcrafted microscope he was the first to observe and describe muscle fibres, bacteria , spermatozoa and blood flow in capillaries (small blood vessels ). His name at birth was Thonis Philipszoon . His letters were signed Antoni van Leeuwenhoek . He was ...

ATPase

... ATPase include cotransporters and pumps (however, some exchangers are also pumps). Some of these, like the Na + /K + ATPase, cause a net flow of charge, but others do not. These are called "electrogenic" and "nonelectrogenic" transporters, respectively. The coupling between ATP hydrolysis ...

Biology

... the evolution of a population of organisms is sometimes depicted as if travelling on a fitness landscape . The arrows indicate the preferred flow of a population on the landscape, and the points A, B, and C are local optima. The red ball indicates a population that moves from a very low fitness ...

Biomechanics

... definitions of the various tensors which are being used in a particular work. Biomechanics of Circulation Under most circumstances, blood flow can be modeled by the Navier-Stokes equations . Whole blood can often be assumed to be an incompressible Newtonian fluid. However, this assumption ...

Blood

... various other proteins various electrolytes (mainly sodium ) Together, plasma and corpuscles form a non-Newtonian fluid whose flow properties are uniquely adapted to the architecture of the blood vessels. Physiology of blood Production and degradation Blood cells are ...

Brain

... over large areas of the brain and very little sub-cortical activity. Functional magnetic resonance imaging (fMRI) measures changes in blood flow in the brain, but the activity of neurons is not directly measured, nor can it be distinguished whether this activity is inhibitory or excitatory. ...

Cell biology

... Purification of cells and their parts Purification of cells and their parts is achieved in the following ways: Cell fractionation flow cytometry Release of cellular organelles by disruption of cells. Separation of different organelles by centrifugation . Proteins extracted ...

Chromatography

... mixture carried by liquid or gas and separates it into its component parts as a result of differential distributions of the solutes as they flow around or over a stationary liquid or solid phase. Various techniques for the separation of complex mixtures rely on the differential affinities of ...

Cytotoxic T cell

... complex, T C cells release the protein perforin , which forms pores in the target cell's plasma membrane ; this causes ions and water to flow into the target cell, making it expand and eventually lyse . T C also release granzyme , a serine protease , that can enter target cells via the ...

Electrical energy

... vectors throughout the volume. (And the reason that Power equals Volts times Current is directly related to the fact that electromagnetic energy flow equals e-field times b-field.) The name of the topic covering production, distribution, and use of electrical energy is electric power . The ...

Endodermis

... the bottom layer of skin . In plants, it is a thin layer of parenchyma found in roots , just outside the vascular cylinder. It regulates the flow of water. Endodermis is tightly packed together and contains Casparian strips on their radial walls which are made of suberin mainly, a waxy ...

Fitness landscape

... function by -1 turns it into a fitness function, and vice versa. Figure 1: Sketch of a fitness landscape. The arrows indicate the preferred flow of a population on the landscape, and the points A, B, and C are local optima. The red ball indicates a population that moves from a very low fitness ...

Fermentation

... from the grain. A mash rest at 104 F or 40 C activates beta-glucanase , which breaks down gummy beta-glucans in the mash, making the sugars flow out more freely later in the process. In the modern mashing process commercial fungal based beta-glucanase may be added as a supplement. A mash rest ...

Hardy-Weinberg principle

... drift ) sexually reproducing randomly mating diploid and experience: no selection no mutation no migration ( gene flow ) Causes of deviation When the Hardy–Weinberg assumptions are not met this can cause deviations from expectation , but depending ...

Insulin

... arterial muscle tone – forces arterial wall muscle to relax, increasing blood flow, especially in micro arteries; lack of insulin reduces flow by allowing these muscles to contract Regulatory action on blood glucose Despite long intervals between meals or the occasional consumption ...

Kidney

... and other nitrogen-rich compounds in the blood. Hydronephrosis is the enlargement of one or both of the kidneys caused by obstruction of the flow of urine. In nephrotic syndrome , the glomerulus has been damaged so that a large amount of protein in the blood enters the urine . Other ...

Konrad Lorenz

... These ideas were influential as ethology became more popular in the 1960s, but they are now regarded as outdated because of their use of an energy flow metaphor; the nervous system and the control of behaviour are now normally treated as involving information transmission rather than energy flow. ...

Light-dependent reaction

... H + . The electrons transfer from the primary acceptor to plastoquinone, then to plastocyanin, producing proton-motive force as with cyclic electron flow and driving ATP synthase. Since the photosystem II complex replaced its lost electrons from an external source, however, these electrons are not ...

Life

... that result in the most future choices, or that which strives to keep its options open. A system converting entropy to negentropy , using flow of energy . Descent with modification: a "useful" characteristic A useful characteristic upon which to base a definition of life is that of ...

Marfan syndrome

... with Marfan syndrome primarily involve the cardiovascular system. Marfan syndrome may cause leakage of the mitral or aortic valves that control the flow of blood through the heart. This may produce shortness of breath, an irregular pulse , and undue tiredness. Another complication is aortic aneurysm ...

Microevolution

... over a few generations, also known as change at or below the species level. These changes may be due to several processes: mutation , gene flow , genetic drift , as well as natural selection . Population genetics is the branch of biology that provides the mathematical structure for the ...

Molecular evolution

... in small mating populations, which simply cannot have enough offspring to maintain the same gene distribution as the parental generation. Gene flow : or gene admixture is the only one of the agents that makes populations closer genetically while building larger gene pools. Selection , in ...

Modern evolutionary synthesis

... ). Evolution consists primarily of changes in the frequencies of alleles between one generation and another as a result of genetic drift , gene flow and natural selection . Speciation occurs gradually when populations are reproductively isolated by geographic barriers. Further advances ...

Oxidative phosphorylation

... to pump a proton against (up) the gradient. Because protons have already been pumped into the intermembrane space against the gradient, they now can flow back into the mitochondrial matrix via the ATP synthase, generating ATP in the process. The reaction is: ADP 3- + H + + P i ↔ ATP 4- ...

Passive transport

... "stick" together via weak hydrogen bonds; therefore, unlike most solutes, water molecules move around in large clumps, a phenomenon known as bulk flow . ...

Polymerase chain reaction

... in addition to the subsequent reaction product analysis, should be performed in separate areas. For the preparation of reaction mixture, a laminar flow cabinet with UV lamp is recommended. Fresh gloves should be used for each PCR step as well as displacement pipettes with aerosol filters. The ...
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