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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.
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 ...
A membrane transport protein is a membrane protein involved in the movement of ions, small molecules, and macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins ; that is they exist permanently within and span the membrane across which they transport substances.
Diffusion vs. Transport. In biology, an ion transporter is a transmembrane protein that moves ions (or other small molecules) across a biological membrane to accomplish many different biological functions, including cellular communication, maintaining homeostasis, energy production, etc. [1] There are different types of transporters including pumps, uniporters, antiporters, and symporters.
Passive diffusion is the unassisted movement of molecules from high concentration to low concentration across a permeable membrane. [2] One example of passive diffusion is the gas exchange that occurs between the oxygen in the blood and the carbon dioxide present in the lungs. [ 3 ]
Comparison of transport proteins. 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 ...
Exocytosis (/ ˌ ɛ k s oʊ s aɪ ˈ t oʊ s ɪ s / [1] [2]) 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). As an active transport mechanism, exocytosis requires the use of energy to transport material.
The basic function, as already mentioned (see: Translocase § Definition), is to "catalyse the movement of ions or molecules across membranes or their separation within membranes". This form of membrane transport is classified under active membrane transport, an energy-requiring process of pumping molecules and ions across membranes against a ...