If a cell is isotonic in a 80% sucrose solution, how will the movement of water across the cell membrane affect the size of a cell if it is moved from an 80% sucrose solution to a 40% sucrose solution?

Being isotonic, the environment and the inside of the cell will have the same concentration. If the cell is placed in a solution of a lesser sucrose solution, the water will enter into the cell making it bigger in size. The movement of the water is from a portion of lower concentration to a portion of higher sucrose concentration. 

If it doesn't have a nucleus its a prokaryote