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Solute pumping is a form of active transport of a solute through a cell membrane. Solute pumping allows a molecule that cannot regularly cross the lipid bilayer (because of concentration gradient, polarity, or other reasons) to enter the cell by way of a protein channel.
6 lip 2017 · Active solute transport is mediated by “pumps” and “carriers” which have different modes of energization; pumps are energized by metabolic energy (and sometime redox or light energy) while active carriers are energized by ionic gradients across the membrane.
1 sty 1995 · Functionally, the ionic pumps represent the primary enzyme systems capable of producing an asymmetric ionic dis tribution across an osmotic (solute-impermeable) membrane barrier, and may be regarded as an energy-transducing device which converts metabolic energy into the osmotic potential energy represented by the of a given ionic species i.
The Na + /K + pump is an active transport pump that moves Na + “uphill” back out of the cell against its concentration gradient, and at the same time moves K + back into the cell against its concentration gradient. This pump requires ATP, a membrane protein transporter, and enzymes, to function.
1 sty 1999 · Some bacteria, in a medium containing sodium, pump sodium out of the cytoplasm into the medium and use the electrochemical gradient of sodium across the membrane to energize other transport functions. In particular, Klebsiella pneumoniae pumps sodium using energy from the decarboxylation of oxaloacetate.
Passive transport is the exergonic movement of substances across the membrane. In contrast, active transport is the endergonic movement of substances across the membrane that is coupled to an exergonic reaction. Passive transport does not require the cell to expend energy.
Some carrier proteins simply transport a single solute “downhill,” whereas others can act as pumps to transport a solute “uphill” against its electrochemical gradient, using energy provided by ATP hydrolysis, by a downhill flow of another solute (such as Na + or H +), or by light to drive the requisite series of conformational changes ...
