A heat-killed, phosphorescent (light-emitting) strain of bacteria is mixed with a living, non-phosphorescent strain. Further observations of the mixture show that some of the living cells are now phosphorescent. Which of the following observations would provide the best evidence that the ability to phosphoresce is a heritable trait?
A) Evidence that DNA was passed from the heat-killed strain to the living strain.
B) Evidence that protein passed from the heat-killed strain to the living strain.
C) Especially bright phosphorescence in the living strain.
D) Phosphorescence in descendants of the living cells.

Question

Quizplus · Accepted Answer

The presence of phosphorescence in descendants of living cells is the best evidence that the ability to phosphoresce is a heritable trait. This suggests that the genetic material responsible for this trait was passed on to the offspring of the living cells. The other options (A, B, C) do not necessarily provide evidence of heritability, as passing of DNA or proteins from the heat-killed strain to the living strain may not result in the offspring inheriting the ability to phosphoresce, and bright phosphorescence may be due to environmental factors rather than genetic inheritance.

A Heat-Killed, Phosphorescent (Light-Emitting) Strain of Bacteria Is Mixed with a Living