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For human systems, see active mobility. 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.
Exocytosis (/ ˌɛksoʊsaɪˈtoʊsɪs / [ 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. Exocytosis and its counterpart ...
proteins. Flow of ions. Alpha and beta units. The sodium–potassium pump (sodium – potassium adenosine triphosphatase, also known as Na+/K+-ATPase, Na+/K+ pump, or sodium–potassium ATPase) is an enzyme (an electrogenic transmembrane ATPase) found in the membrane of all animal cells. It performs several functions in cell physiology.
The ascending limb of the loop of Henle is a direct continuation from the descending limb of loop of Henle, and one of the structures in the nephron of the kidney. The ascending limb has a thin and a thick segment. The ascending limb drains urine into the distal convoluted tubule. The thick ascending limb is found in the medulla of the kidney ...
A comparison of transport proteins 1. An antiporter (also called exchanger or counter-transporter) is an integral membrane protein that uses secondary active transport to move two or more molecules in opposite directions across a phospholipid membrane. It is a type of cotransporter, which means that uses the energetically favorable movement of ...
In contrast, paracellular transport is the transfer of substances across an epithelium by passing through an intercellular space between the cells. 1. It differs from transcellular transport, where the substances travel through the cell passing through both the apical membrane and basolateral membrane. 2. Renal physiology.
Mass movement of sodium occurs through the cells, by secondary active transport on the apical membrane, followed by active resorption across the basolateral membrane via the Na + /K +-ATPase. [10] The solutes are absorbed isotonically , in that the osmotic potential of the fluid leaving the proximal tubule is the same as that of the initial ...
Glucose. Glucose transporters are a wide group of membrane proteins that facilitate the transport of glucose across the plasma membrane, a process known as facilitated diffusion. Because glucose is a vital source of energy for all life, these transporters are present in all phyla.