In cotransport, a membrane protein couples the transport of two solutes. A single ATP-powered pump that transports one solute can indirectly drive the active transport of several other solutes in a mechanism called cotransport. As the solute that has been actively transported diffuses back passively through a transport protein, its movement can be coupled with the active transport of another substance against its concentration gradient. Plants commonly use the gradient of hydrogen ions generated by proton pumps to drive the active transport of amino acids, sugars, and other nutrients into the cell. One specific transport protein couples the diffusion of protons out of the cell and the transport of sucrose into the cell. Plants use the mechanism of sucrose-proton cotransport to load sucrose into specialized cells in the veins of leaves for distribution to nonphotosynthetic organs such as roots. Concept 8.5 Bulk transport across the plasma membrane occurs by exocytosis
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.