In this chapter, we focused on the regulation of gene expression in bacteria. Along the way, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions? How do we know that bacteria regulate the expression of certain genes in response to the environment?

Video transcript

Hi everyone welcome back. Let's look at our next problem. It says identify the correct statement about the regulation of the lac opteron and bacteria. So let's look at our answer choices here twice A says it responds differently to different concentrations of galactose in the environment. Well this is incorrect. Um It doesn't respond to different concentrations of galactose. It responds to different concentrations of lactose and of glucose when lactose is present. Um It gets induced. The repressor protein is released from its binding site when glucose is low the mall. The cell produces C. A. M. P. Which binds to the cap protein which binds the cap binding site and enhances transcription. Then we look at Choice B. It is switched on in the absence of lactose. Well this is incorrect. Um You wouldn't want it being produced in the absence of lactose because it's to produce enzymes that digest lactose. So it switched on in the presence of active tWIC says lactose binds the repressor, causing it to remain on the operator. Well, this is also incorrect. Lactose does bind the oppressor or more specifically a low lactose. It's isOM or binds the oppressor but that causes it to be removed from the operators from the operator that allows transcription to go forward. And then finally Choice D. Says the Black sea gene encodes beta galactose oxidase which converts lactose into glucose and galactose. And this is correct. That is what the easy gene does. So since that is our correct statement. That is our answer. So identify the correct statement about the regulation of the lac operator bacteria. Choice D. Galaxy gene encodes basic black societies, which converts lactose into glucose and galactose. See you in the next video.