Two different species of ciliate are placed in a solution with an unknown solute concentration. Ciliate A has a contractile vacuole firing rate of 5 per minute; ciliate B has a contractile vacuole firing rate of 12 per minute. Which of the following is a reasonable conclusion based on these observations?
A) Ciliate A has a greater solute concentration than ciliate B.
B) Ciliate B has a greater solute concentration than ciliate A.
C) The solution has a greater solute concentration than ciliate A.
D) The solution has a greater solute concentration than ciliate B.
E) No conclusions can be made unless we know the solute concentration of the solution.

Question

Quizplus · Accepted Answer

Ciliate B has a higher contractile vacuole firing rate, which means it needs to pump out more water to maintain its osmotic balance. This indicates that ciliate B is in a more hypotonic environment (higher solute concentration) than ciliate A. Therefore, option B is the best choice.

Two Different Species of Ciliate Are Placed in a Solution