Problem: Plant cells utilize co-transport to power the active transport of sucrose through a process involving proton pumps and cotransporters. Here's how it works: Proton Pumps: These pumps use ATP to move hydrogen ions (H?) out of the cell, creating a high concentration of H? outside the cell. This gradient represents stored energy. Cotransporters: The H? ions naturally want to move back into the cell down their concentration gradient. Cotransporters harness this movement to transport sucrose into the cell against its concentration gradient. The sucrose can only enter the cell when coupled with the inward movement of H? ions. Sucrose Loading: This mechanism is crucial for loading sucrose produced by photosynthesis into the phloem, which then distributes it to various parts of the plant. Summarize This. Need Assignment Help?