Question

Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. the presence of these organelles tells you that the intracellular environment of the protozoan is _______________ relative to the extracellular environment.

Answer 1

Answer is hypertonic.

The ability of an extracellular solution to make water move into or out of a cell by osmosis is known as its tonicity. Tonicity is concern for all living things, especially in in organisms lacking cell wall, Paramecium is one such protozoan. It has specialized structures called contractile vacuoles. A contractile vacuole collects excess water from the cell and release it out, keeping the cell from lysing as it takes on water from extracellular environment which hypotonic (a lower osmolarity than the cell’s cytoplasm) as compared to hypertonic environment inside Paramecium.