Suppose the lac operon partial diploid cap⁻ I⁺ ...

Question

Suppose the lac operon partial diploid cap⁻ I⁺ P⁺ O⁺ Z⁻ Y⁺/ cap⁺ I⁻ P⁺ O⁺ Z⁺ Y⁻ is grown.

Is transcription of -galactosidase and permease inducible, constitutive, or noninducible?

Accepted Answer

Hi, everybody. Let's look at our next question. Which of the following cases gives an example of a noninducible lack operon choice, a mutation, and lax Z gene choice B mutation and lack zine gene choice C mutation and lack I gene or D. All options are correct. So let's recall what an inducible operon is. And that would be one where you can increase the transcription of genes in response to cellular conditions. So you have some sort of signaling molecule that responds to certain cellular conditions and causes transcription to increase. So when would the la opera not be inducible? Well, the lax C and lack Y genes mentioned in A and B are structural genes, they code for proteins that metabolize lactose and cells. So a mutation in those genes would just result in not being able to express their gene. It doesn't affect the, whether or not the gene, the operon is inducible. So that's why those answer choices are not correct and therefore choice D all options are correct is not our answer. So let's focus here on choice C mutation in the lack I gene. Well, the lack I gene codes for the lack repressor and the lac repressor is usually how the inducible lac operon works in the presence of lactose, an isomer of lactose, allo lactose binds the lac repressor, releasing it from its operator binding site and allowing the transcription to go forward. If there's a mutation in the gene for that repressor, then in this situation, there's no repressor molecule and the lac genes are therefore continuously expressed regardless of the presence or absence of lactose. So they're no longer inducible. There's nothing that's going to turn up the transcription of the gene. So that's why choice C is our answer here. Which of the following cases gives an example of a noninducible lac operon choice C mutation and the lac igene. See you in the next video.

Suppose the lac operon partial diploid cap⁻ I⁺ P⁺ O⁺ Z⁻ Y⁺/ cap⁺ I⁻ P⁺ O⁺ Z⁺ Y⁻ is grown.

Is transcription of -galactosidase and permease inducible, constitutive, or noninducible?

Key Concepts

Lac Operon Structure

Inducible vs. Constitutive Expression

Partial Diploidy

Watch next

Suppose the lac operon partial diploid cap⁻ I⁺ P⁺ O⁺ Z⁻ Y⁺/ cap⁺ I⁻ P⁺ O⁺ Z⁺ Y⁻ is grown.Is transcription of -galactosidase and permease inducible, constitutive, or noninducible?

Key Concepts

Lac Operon Structure

Inducible vs. Constitutive Expression

Partial Diploidy

Watch next

Suppose the lac operon partial diploid cap⁻ I⁺ P⁺ O⁺ Z⁻ Y⁺/ cap⁺ I⁻ P⁺ O⁺ Z⁺ Y⁻ is grown.

Is transcription of -galactosidase and permease inducible, constitutive, or noninducible?