Biology Test 3

Last update by Shanal on 10/31/2013
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Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Plant cells continuously produce a proton gradient by using the energy of ATP hydrolysis to pump protons out of the cell. Why, in the absence of sucrose, don't protons move back into the cell through the sucrose-proton cotransport protein?

Answer:
The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time.

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