Question

How would the contractile vacuole of a freshwater amoeba respond if the organism was placed in seawater

Answer 1

The vacuole would quickly shrink in size as water would leave the amoeba because of a higher salt concentration outside the cell.

Answer 2

The single cell organisms such as Amoeba contains special type of vacuole called contractile vacuole. It balances water in the cell by contraction and relaxation.

Sea water contains lots of salt and is hypertonic to the water present in the contractile vacuole of Amoeba. When Amoeba is put into the sea water, it loses water due to exosmosis from the contractile vacuole. As a result, Amoeba shrinks and gets plasmolysed.