Question

when amoeba is placed in a hypertonic medium it shrinks

Answer 1

A hypertonic environment for a cell is created when the solution outside of the cell is hypertonic in comparison to the cytoplasm of the cell. The amoeba has more dissolved solute than the cytoplasm of the cell. In this situation, water is in higher concentration inside the cell and will move, by osmosis, to the outside in an attempt to equalize the concentrations. Water leaving the cell will cause shrinkage of the cell and a loss of mass. Thus, it shrinks not bursts.

Answer 2

Hypertonic solutions is a solution which has concentration more than the outside the solution. When amoeba is placed in a hypertonic solutions it loses water by exosmosis because there is a concentration gradient which is set up there then it loses water and shrinks in size and then eventually dies.