Loading of sucrose into the phloem at a source requires the plant to expend energy. How is sucrose loaded into the phloem against its concentration gradient?

+2 votes

 

Protons are pumped out of the cell through proteins. They diffuse back into the cell through cotransporters, which allow sucrose through at the same time.

Protons are pumped out of the cell through proteins. Sucrose is pumped into the cell at the same time and through the same proteins.

ATP is used to pump sucrose into the cell.

Sucrose diffuses into the phloem.

 

asked Dec 30, 2012 in Biology by anonymous
    

1 Answer

+1 vote

 

Protons are pumped out of the cell through proteins. They diffuse back into the cell through cotransporters, which allow sucrose through at the same time.

 

answered Dec 30, 2012 by JaFajx ~Expert~ (464 points)



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