Theoretically, P.bursaria can obtain zoochlorella either vertically (via the asexual reproduction of its mother cell)or horizontally (by ingesting free-living Chlorella from its habitat). Consider a P. bursaria cell containing zoochlorellae, but whose habitat lacks free-living Chlorella. If this cell subsequently undergoes many generations of asexual reproduction, if all of its daughter cells contain roughly the same number of zoochlorellae as it had originally contained, and if the zoochlorellae are all haploid and identical in appearance, then what is true?
A) The zoochlorellae also reproduced asexually, at an increasing rate over time.
B) The zoochlorellae also reproduced asexually, at a decreasing rate over time.
C) The zoochlorellae also reproduced asexually, at a fairly constant rate over time.
D) The zoochlorellae reproduced sexually, undergoing heteromorphic alternation of generations.
E) The zoochlorellae reproduced sexually, undergoing isomorphic alternation of generations.

Question

Quizplus · Accepted Answer

If all daughter cells contain roughly the same number of zoochlorellae as the original cell, it suggests that the zoochlorellae are being faithfully passed down through asexual reproduction. This means that the zoochlorellae are reproducing at a fairly constant rate over time, as new zoochlorellae are being produced at the same rate that old ones are being passed on to daughter cells. This is also consistent with the scenario presented, where the habitat lacks free-living Chlorella and there is no indication of sexual reproduction or alternation of generations.