If the concentration of solute (salt) is equal on both sides of the cell membrane, the water will move back in forth but it won't have any result on the overall amount of water on either side.

In this case there are less solute (salt) molecules inside the cell. Water's concentration is greater outside the cell, so water will move into the cell.

The cell will gain water and grow larger. In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid, the cell wall keeps the plant from bursting

In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES will pump water out of the cell to prevent this.

In this case there are more solute (salt) molecules outside the cell. Water's concentration is greater inside the cell so will move out (toward the lower concentration).

In plant cells, the central vacuole loses water and the cells shrink, causing wilting.

In animal cells, the cells also shrink.

In both cases, the cell may die.