Transcriptional regulation of operon gene expression involves the...

Question

Transcriptional regulation of operon gene expression involves the interaction of molecules with one another and of regulatory molecules with segments of DNA. In this context, define and give an example of each of the following:

allostery

Accepted Answer

Hi, everyone. Let's look at our next question. It says which of the following statements best describes the interaction between allo lactose and lac repressor protein. But we're going to read through and evaluate our answer choices. But first, let's just briefly think about alo lactose and lack repressor. We know that the lac repressor is usually bound to the operator, thereby blocking access to the promoter site of the lac operon. So R N A polymerase cannot come in and transcribe those genes for the metabolism of lactose. This is to prevent these genes, you know, energy going into producing these proteins when there's no lactose around when lactose is present. So therefore, it's maybe worth the time and energy to produce those proteins that can digest lactose. Then some of the lactose is converted to its isomer ally lactose, which binds to that lacer protein releasing it from the operator which then makes the promoter accessible or an ale and rice can come in and transcribe those genes. So with that in mind, let's read through our answer choices and evaluate which one best describes this interaction between alo lactose and the lac pressure choice. A says Allo lactose binds to the promoter sequence, thereby preventing lac repressor protein from binding to the operator site. Well, this is not the description of their interaction. As we saw, ali lactose binds directly two, the repressor protein, not the promoter sequence. So choice A is not correct. Choice. B says ally lactose binds directly to the Laro pressure protein causing a confirmational change that reduces its affinity for the operator site. Well, this is a correct description of their interaction that binding to the lack repressor protein. The way it releases it from the operator is that it causes the repressor protein to have a confirmational change that reduces its affinity for the operator site. So instead of being bound tightly to that operator, it changes and is released allowing the R N A plume race to come in and have access to the promoter. So we have this answer here. But to be thorough, we'll look at our other answer. Choices. Choice C says a lactose binds to the R N A polymerase facilitating its interaction with the promoter sequence. Well, this is not correct as we saw, ali lactose binds to the repressor. So choice C is not our answer. And then finally, choice D ay lactose binds the regulatory protein thereby inducing a positive allosteric effect on the lac pro protein. Again, we know that alo lactose binds directly to the lac repressor. Um It's definitely not interacting with regulatory proteins that might have a positive allosteric effect. We know that poly positive allosteric effects cause enhancement of the binding ability of something that would cause a boosting of a signal or increased activity. And that is not how a lactose works. It binds directly to that repressor causing it to be released. So choice D is not correct as a description of their interaction. So once again, which of the following statements best describes the interaction between alo lactose and lac repressor protein choice. B alo lactose binds directly to the lac repressor protein causing a confirmational change that reduces its affinity for the operator site. See you in the next video.

Transcriptional regulation of operon gene expression involves the interaction of molecules with one another and of regulatory molecules with segments of DNA. In this context, define and give an example of each of the following: allostery

Key Concepts

Allostery

Operon

Transcriptional Regulation

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