Question

A paramecium is a single-celled organism that contains one or more organelles called contractile vacuoles. In its freshwater environment, water may accumulate inside the paramecium and the contractile vacuoles. Contraction of the vacuoles removes excess water from the organism, thus preventing the paramecium from bursting. Table 1 provides internal and external water potentials W for four different paramecia living in four different environments.

A.Paramecium 1
B.Paramecium 2
C.©
Paramecium 3
D.Paramecium 4

Answer 1

We can see here that Paramecium 3 have highest contraction rate.

Why is it so?

The water potential that would likely lead to the highest contraction rate in a paramecium would be a hypotonic solution.

Paramecia are single-celled organisms with contractile vacuoles that help regulate water intake and prevent the cell from bursting due to osmotic pressure. When placed in a hypotonic solution (a solution with lower solute concentration compared to the cell's cytoplasm), water moves into the paramecium by osmosis, causing the cell to swell.

The measure of water potential in a hypotonic solution can be described as having a higher water potential compared to the internal environment of a cell or organism.