Transport213-page4

Transport213-page4 - Transport in Plants - 4 Negative ion...

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Transport in Plants - 4 Negative ion movement can be coupled to H + flow along the H + gradient. The negative charges are attracted to the H + and can be moved against their gradient, in a process called cotransport. Cotransport of negative ions Cotransport of neutral solutes Cotransport is also used to move neutral solutes such as sucrose against a gradient. As H + moves down its gradient it is coupled to a substance being moved against its gradient. Sugar is loaded and unloaded from phloem sieve tubes by cotransport. Use of proton pumps for solute movement is a variant of the general process of chemiosmosis, which generates ATP in photosynthesis and cell respiration. To add to the information about membranes and membrane transport, we also need a brief diversion on water potential before discussing the transport of water in cells and throughout the plant body. Water in? Water out? – The Water Potential ( ± ) Discussion
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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