A species of algae consists of aggregates of cells that have different functions.Researchers suspect that the outer, motile cells of this species produce a chemical signal that travels to the inner reproductive cells, causing them to lose their flagella and divide.Which experimental approach would best provide evidence in support of a chemical signaling agent acting to cause the observed change in cells?
A) Examine mutants that cannot progress to the reproductive phase for their ability to use flagella to move through their environment.
B) Insert genes from this species into a non-aggregating species to see if the non-aggregating species can acquire the ability to aggregate and specialize.
C) Add molecules secreted by normal algae to the medium containing mutant algal cells that cannot progress to the reproductive phase, and incubate them to see if reproduction can be induced.
D) Test various environmental cues, such as variations in lighting and temperature, to determine which cues, if any, trigger inner cells to lose their flagella and divide.
E) Break apart aggregates of cells, and then test to see whether the cells can reassemble on their own and work cooperatively in their specialized roles.

Question

Quizplus · Accepted Answer

Adding molecules secreted by normal algae to the medium containing mutant algal cells is the best approach because it directly tests the hypothesis that a chemical signaling agent is responsible for the observed change in cells. The other options do not directly test this hypothesis or do not provide a clear way to measure whether the signaling agent is present and functional.

A Species of Algae Consists of Aggregates of Cells That