Erythritol, a natural sugar abundant in fruits and fermenting foods, is about 65 percent as sweet as table sugar and has about 95 percent fewer calories. It is 'tooth friendly' and generally devoid of negative side effects as a human consumable product. Pathogenic Brucella strains that catabolize erythritol contain four closely spaced genes, all involved in erythritol metabolism. One of the four genes (eryD) encodes a product that represses the expression of the other three genes. Erythritol catabolism is stimulated by erythritol. Present a simple regulatory model to account for the regulation of erythritol catabolism in Brucella. Does this system appear to be under inducible or repressible control?

Video transcript

Hi everyone. Let's take a look at this practice problem together. The lack Oberon has genes that are involved in lactose metabolism. It is expressed only if molecules of lactose are detected in this case lack operation is considered as. So the lack Operandi is present in bacteria and it is involved in lactose metabolism and it is turned on only when lactose is present in the bacteria cell. So is the black op aran and induce a ble ah peron. Is it an enhancer? Ah Peron? Is it a repressive Operandi or is it a silencer? Operandi? So what is the definition of an Opera Ron? Well an operation is a piece of D. N. A. With jeans of similar function and they are transcribed together. Now we can eliminate enhancer and silencer. Operandi there are no such thing as this type of Operandi. Now there are enhancers and there are silencers but recall that these are regulatory elements of D. N. A. So they are portions of D. N. A. And they affect the rate of transcription so they affect transcription. Therefore they are not operations. So we are left with either the repress herbal operation or the induce a ble chaperon. Now repress herbal means to inhibit whereas induce a ble means to turn on. So a repressive operation would be an operation that was switched off in response to its regulatory molecule. So if lack operation was a repressive operate on it would be turned off when lactose was present and this is the opposite of what the lack Operandi does because it is turned on by lactose. It is an induce a ble operandi. So our answer is a induce a ble opera on. Alright, everyone. I hope you found this helpful, and I'll see you soon for the next practice problem.