When microbes are in the dark, they do not produce molecules called carotenoids because the PR proteins are bound to DNA. In the light, however, carotenoids are produced because the PR proteins unbind the DNA. Which of the following graphs best summarizes these statements about carotenoid production in microbes?

Question

Quizplus · Accepted Answer

Graph B shows a clear increase in carotenoid production in response to light, while in the dark the production is significantly reduced. This is consistent with the statement that PR proteins unbind from DNA in the light, allowing for the production of carotenoids, while in the dark, they remain bound to DNA, preventing carotenoid production. The other graphs do not show such a clear correlation between light exposure and carotenoid production.

When Microbes Are in the Dark, They Do Not Produce