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Topic: Active transport

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In the News (Thu 23 May 19)

  Transport Across Cell Membranes
Active transport is the pumping of molecules or ions through a membrane against their concentration gradient.
Direct active transport of the ion establishes a concentration gradient.
The Na /glucose transporter is used to actively transport glucose out of the intestine and also out of the kidney tubules and back into the blood.
users.rcn.com /jkimball.ma.ultranet/BiologyPages/D/Diffusion.html   (2816 words)

  Active transport - Wikipedia, the free encyclopedia
Active transport is the mediated transport of biochemicals, and other atomic/molecular substances, across membranes.
The active transport of small molecules or ions across a cell membrane is generally carried out by transport proteins that are found in the membrane.
In secondary active transport, there is however no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of cells is used.
en.wikipedia.org /wiki/Active_transport   (542 words)

 Active Transport - Search Results - MSN Encarta
Active Transport, energy-using process in microscopic living cells, whereby a cell can move dissolved substances through its membranes or “skin”...
Transport of the products of digestion through the wall of the small intestine may be either passive or active.
The coupling of the transfer of electrons to oxygen to the synthesis of ATP is known as the process of oxidative phosphorylation.
uk.encarta.msn.com /Active_Transport.html   (133 words)

 5 Membrane Transport Mechanisms
Active transport requires the expenditure of energy to transport the molecule from one side of the membrane to the other, but active transport is the only type of transport that can actually take molecules up their concentration gradient as well as down.
Similarly to facillitated transport, active transport is limited by the number of protein transporters present.
Secondary active transport involves using energy to establish a gradient across the cell membrane, and then utilizing that gradient to transport a molecule of interest up its concentration gradient.
www.bgsu.edu /departments/chem/midden/MITBCT/mem/transport.html   (738 words)

 CAMWEST Features — Transport and Health
Active transport, walking and cycling, is the way to go: it will keep people active sustainably, because it becomes part of everyday life.
Transport can be health promoting especially if car dependence is avoided and greater opportunity is made of active transport, the use of public transport, cycling and walking.
Active Transport, a health term, is defined as physical activity undertaken as a means of transport and not purely as a form of recreation.
camwest.pps.com.au /news/healthy_transport.shtml   (1842 words)

 Membrane Transport Mechanisms   (Site not responding. Last check: )
The center of the barrel could constitute a hole in the plasma membrane that is isolated from the lipid bilayer by an array of transmembrane domains around it.
Similarly to facilitated transport, active transport is limited by the number of protein transporters present.
Primary active transport involves using energy (usually through ATP hydrolysis) at the membrane protein itself to cause a conformational change that results in the transport of the molecule through the protein.
web.mit.edu /esgbio/www/cb/membranes/transport.html   (738 words)

 Transport protein - Wikipedia, the free encyclopedia
A transport protein is a protein involved in the movement of a chemical across a biological membrane.
Transport proteins are also used in active transport, which by definition requires an energy input.
A symporter/coporter transports a chemical in the same direction as the electrochemical gradient, while an antiporter moves the target chemical in a direction opposite to the gradient.
en.wikipedia.org /wiki/Transport_protein   (360 words)

 active transport   (Site not responding. Last check: )
Active transport refers to a process in which a substances is transported across a membrane by the use of an integral membrane protein (or protein complex) that has ATPase activity.
The ATPase activity of the transport protein makes it possible for the substance to be transported against a concentration gradient of that substance.
ATP is required because the movement of a substance against a concentration gradient of that substance is an endergonic process.
academic.brooklyn.cuny.edu /biology/bio4fv/page/active_t.htm   (81 words)

 Botany online: Membranes and Transport - Active Transport   (Site not responding. Last check: )
Active transport is the movement of a molecule across a membrane or another barrier that is driven by energy other than stored in the concentration gradient or the electrochemical gradient of the transported molecule.
A proton is transported into a compartment and the energy for the transport is supplied by the simultaneous transport of an anion or a substrate molecule in the same direction.
The transport is initiated by a chemical reaction during which the substrate is 'phosphorylated into the cell'.
www.biologie.uni-hamburg.de /b-online/e22/22d.htm   (1230 words)

Ion transport (for the most part ion transport is under the same principles as discussed for facilitated diffusion and the to be discussed phenomenon of active transport)
Active transport - the use of energy in forcing a molecule across a membrane.
Active transport can be used to develop a charge gradient if the molecule being actively transported is an ion.
www.mrs.umn.edu /~goochv/CellBio/lectures/transport/transport.html   (2232 words)

 active transport
The pumping of individual ions or other molecules across a cell membrane, through the use of a protein, from a region of lower concentration to one of higher concentration.
Because the ion or molecule is moved in a direction other than the one in which simple diffusion would take it, this transport requires energy, which is typically supplied by the expenditure of ATP.
Primary active transport uses energy directly to convey molecules across a membrane.
www.daviddarling.info /encyclopedia/A/activetransport.html   (293 words)

 Active Transport   (Site not responding. Last check: )
Active Transport started out as a piano, tenor saxophone and trumpet player looking to find their bass player and drummer at Skidmore Jazz Institute in the summer of 2001.
Active Transport will be playing at the well-known Caffe Lena in Saratoga, NY on October 6.
Active Transport has added new originals to their repetoire.
members.tripod.com /activetransport_jazz   (287 words)

 Botany online: Membranes and Transport   (Site not responding. Last check: )
Exchange of molecules through membranes depends on highly specific transport systems, prominent representatives of this group are the porines that extensively have been studied in bacteria.
It is also spoken of an active transport in contrast to passive transport that occurs only in the direction of the concentration gradient.
Active transport can be understood when knowing structure and function of integral proteins and the electrochemical properties of the membrane while the understanding of energy transformation requires information about all the molecules within the respective membrane.
www.biologie.uni-hamburg.de /b-online/e22/22.htm   (1136 words)

 Active transport of CO2 and bicarbonate is induced in response to external CO2 concentration in the green alga ...
Active transport of CO2 and bicarbonate is induced in response to external CO2 concentration in the green alga Chlorella kessleri -- Bozzo et al.
Active transport of CO and bicarbonate is induced in response to external CO concentration in the green alga Chlorella kessleri
Active uptake of inorganic carbon by Chlorella saccharophila is not repressed by growth in high CO Journal of Experimental Botany 47, 1951–1956.
jxb.oxfordjournals.org /cgi/content/full/51/349/1341   (4207 words)

 Active Transport
Active transport involves expenditure of metabolic energy to move ions or other solutes across membranes against their electrochemical gradient.
In such cases, the free energy released during the transport of ions down an electrochemical gradient is used to pump other ions or molecules up their electrochemical gradient.
Sodium-proton cotransport involves transport of a sodium ion into the cell coupled to transport of a hydrogen ion out of the cell; both ions are transported by the same carrier protein.
arbl.cvmbs.colostate.edu /hbooks/cmb/cells/pmemb/transport_active.html   (994 words)

 active logistics GmbH - Speditions-, Transport-, Lager- und Logistiksoftware
active logistics erweitert Rechenzentrum - Vertragsunterzeichnung auf der CeBIT -
Die neue Position bei active logistics bedeutet für Baumann eine Rückkehr in den Mittelstand, den er in der sechsjährigen Tätigkeit für die Heyde AG an verschiedenen Standorten im In- und Ausland schätzen gelernt hatte.
Januar 2008 die Funktion des Sprechers der Geschäftsführung der active logistics GmbH in Herdecke und auch die Gesamtverantwortung für die active logistics Gruppe übernommen.
www.active-logistics.com   (1297 words)

 Active Transport Services Inc.
Active Transport Has a Variety of Shipping Methods to Suit Your Needs
If you are like most cost-conscious businesses, you only use a messenger service when your parcel or letter has to be somewhere today.
We are New York's same day link to the business world, offering you immediate messenger service and direct delivery to all business districts, along with services to the entire Greater Metropolitan and TriState Area.In addition we offer a variety of services for the small business user such as small bulk mailings.
www.activetransport.net   (141 words)

 Active Transportation
This publication discusses the health and environmental effects of transportation including noise, accidents and injuries, air pollution, mental health issues, and the role of walking and bicycling.
Neighborhood comparison and correlational studies with nonmotorized transport outcomes are considered, with evidence suggesting that residents from communities with higher density, greater connectivity, and more land use mix report higher rates of walking/cycling for utilitarian purposes than low-density, poorly connected, and single land use neighborhoods.
This research shows that transportation costs are highest in sprawling places, while less sprawling places that offer a variety of transportation alternatives cost families less.
www.activetransportation.org /resources_articles.htm   (1668 words)

 Molecule Transport
However, the means that cells use to transfer small molecules are not sufficient for transporting macromolecules, which include proteins, polynucleotides, and polysaccharides.
There are two basic means of active transport - by exocytosis and by endocytosis.
They are then transported to the Golgi complex by ER induced vesicles.
library.thinkquest.org /C004535/molecule_transport.html   (673 words)

 A to H
Active transport is the carriage of a solute across a biological membrane from low to high concentration that requires the expenditure of (metabolic) energy.
A bioprecursor prodrug is a prodrug that does not imply the linkage to a carrier group, but results from a molecular modification of the active principle itself.
A carrier-linked prodrug is a prodrug that contains a temporary linkage of a given active substance with a transient carrier group that produces improved physicochemical or pharmacokinetic properties and that can be easily removed in vivo, usually by a hydrolytic cleavage.
www.chem.qmul.ac.uk /iupac/medchem/ah.html   (2005 words)

 The Pedestrian Council : Information Sheet on Active Transport and Walking
Use of public transport is also included in the definition as it often involves some walking or cycling to pick-up and from drop-off points.
The car oriented design inherent in transportation systems and perceived lack of choice by individuals has seen increasing reliance on the car, associated traffic congestion, less walking of short distances and increased sedentary behaviour as we spend more time driving.
Walking should be a primary and vital transport mode, part of every journey, yet it has been virtually forgotten as we have increasingly become a car-dependent culture.
www.walk.com.au /wtw/Page.asp?PageID=1265   (429 words)

 Active Transport Lecture
Ions and large food particles must be transported into a cell across membranes generally impermeable to them.
Waste products must be removed from the cytoplasm, and other molecules or ions are actively pumped in one direction or the other to create concentration gradients which can be used to do other tasks.
Membranal carriers, transmembranal proteins or peripheral proteins, are able to change shape in such a way as to open a passage for a specific molecule, allowing it to diffuse from one side of the membrane to the other.
home.earthlink.net /~dayvdanls/cell_membrane2.htm   (433 words)

 Passive Transport vs
In active transport it is possible to go against the concentration gradient.
In active transport, a source of energy is required to move the carrier and its materials.
An example of primary active transport is the sodium pump.
biology.kenyon.edu /HHMI/Biol113/passive_vs_active.htm   (127 words)

 Biology4Kids.com: Cell Function: Active Transport
Active transport, simply put, happens when a cell uses energy to transport something.
Active transport is usually done across the cell membrane.
It is those proteins that do much of the work of active transport.
www.biology4kids.com /files/cell2_activetran.html   (335 words)

 Active Cabarete - transport from Santo Domingo to Cabarete
Traveling by taxi is usually the fastest and most reliable form of transport from Santo Domingo to Cabarete.
You'll enjoy beautiful views of the lush mountains and valleys that separate the fertile Central Valley of the Dominican Republic and the golden shores of the North.
This is the least expensive transportation option but it can be quite a long journey after hours of flight travel.
www.activecabarete.com /info/travel-from-santo-domingo.php   (725 words)

 Active Air Cargo hjälper dig med dator transport - Active Air Cargo
Active Air Cargo kan erbjuda transport till Europa för privatpersoner och företag.
Active Air Cargo bryr sig om ditt djur och erbjuder omtänksamma och humana djurtransporter från Arlanda Flygplats.
Active Air Cargo erbjuder effektiva och snabba logistiklösningar både för privatpersoner och företag.
aac.nets.se   (187 words)

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