Question

From the Luria-Delbruck fluctuation test, when would mutations arise in yeast cells to allow for survival in the presence of toxic levels of hydrogen peroxide? Mutations are adaptive and would have appeared immediately in response to the hydrogen peroxide. Mutations are random and would have appeared prior to being exposed to hydrogen peroxide. Mutations are adaptive and would have appeared after most of the cells died in the presence of hydrogen peroxide. Mutations are adaptive and would have formed prior to being exposed to hydrogen peroxide. Mutations are random but would not have formed until after the hydrogen peroxide was introduced.

Answer 1

Option 2nd is the correct answer.

According to Luria-Delbruck fluctuation test mutations occurs randomly and occurs in the absence of selection rather than being a response to selection. Thus, according to Luria-Delbruck mutation in yeast for survival in the presence of toxic level of hydrogen peroxide occurs randomly and would have appeared before exposure to hydrogen peroxide. It means mutations occurs randomly and selected during exposure.