Propose a hypothesis accounting for these results

Q1. An experiment is planned to study mechanism of sucrose uptake by plant cells. Cells are immersed in a sucrose solution, and pH of the solution is monitored. Samples of the cells are taken at intervals, and their sucrose concentration is measured. Their sucrose uptake correlates with a rise in the solution’s pH. This rise is proportional to the starting concentration of sucrose in the solution. A metabolic poison is that blocks the capability of cells to regenerate ATP is found to inhibit the pH changes in the solution. Propose a hypothesis accounting for these results. Suggest an experiment to test it.

Q2. Carotenoids are frequently found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?