Suppose an operon has the following characteristics: (1) the operon codes for structural proteins that convert compound q to compound

Suppose an operon has the following characteristics: (1) the operon codes for structural proteins that convert compound q to compound b. (2) the operon is controlled by a constitutively expressed regulatory gene called reg. (3) in wild-type individuals, the operon is transcribed in the absence of compound b but not in the presence of compound b. (4) in reg- mutants, the operon is constitutively transcribed. is this operon inducible or repressible? why?

Answers

It is repressible because wild-type transcription is repressed in the presence of Compound B

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It is repressible because wild-type transcription is repressed in the presence of Compound B

Explanation:

An operon is a segment of DNA containing adjacent genes including structural genes, an operator gene, and a regulatory gene. In other words you can say it is the functional unit of transcription and gene regulations.

There are 3 types of operons

1) inducible operon- this system is a regulated unit of genetic material which is switched on in response to the presence of a chemical. Means that transcription is turned on when a specific molecule is present.

2) Repressible Operon: in this system, transcription stops when the repressor gene product is activated and the sufficient amounts of the gene product inhibit further transcription.

The third is Constitutive Operon: in this case, the amount of gene product is constant.

2b. 3a. 4d. 5a.

Explanation:

1. Summary

trpP - Malfunction promotertrpOc - Malfunction operatortrpR - Malfunction repressor protein (non-working protein)trpRs - Repessor protein overworks

2. Partial diploid: trpR + trpOc/ trpRs + trpOc

b. trp genes will not be expressed; trpOc is dominant.A gene includes promoter, operator, and coding region, in which the promoter and operator play a role in controlling gene expression.Because trpOc makes the operator not to accept repressor protein. It means that whatever the repressor proteins, the gene will not be expressed. And thus, trpOc is more dominant.

3. Rnovel: repressor protein cannot bind to DNA, but can make dimers.

a. constitutiveBecause repressor protein cannot bind to DNA and regulate gene expression. DNA gene expression is continued.

4. trpRnovel & trpO+/ trpR+ & trpO+

d. The expression of trp genes will be constituted. trpRnovel is dominant.trpRnovel leads to repressor protein not binding to DNA, then it is dominant than the normal one.

5. trpR d- & trpO+/ trpRs & trpO+

a. There will be no expression of trp genes. trpRd-is recessive.trpRd- is a negative mutation, so it does not affect the work of the protein.trpRs produces sensitive repressor protein, which will block the expression.

a. inducible

Explanation:

An inducible gene is a gene that is expressed only when its product is needed, and is expressed only in the presence of a substance (an inducer) in the environment. This substance can control the expression of one or more genes (structural genes) involved in the metabolism of that substance. For example, lactose induces the expression of lac genes that are involved in lactose metabolism. And certain antibiotics can induce expression of a gene that leads to resistance to that antibiotic.

Inducible, because wild type transcription occurs in the presence of pigment A.

Explanation:

In the question, we were given that color operon codes for structural genes that convert pigment A to pigment C and is regulated by a gene called Paint. Since transcription occurs in the presence of pigment A then it means pigment A induces the transcription. This makes it Inducible, because wild type transcription occurs in the presence of pigment A.

Repressor and repressible.

Explanation:

Operon may be defined as the functional unit of the DNA that contains the cluster of genes. These genes are transcribed by the single promoter and works as polycistronic gene.

The blob operon is inactive in the presence of the B. Here, Gene S may acts as a repressor protein and requires the  B compound to work as a corepressor. The blob operon acts as the repressible as it is inactive in the presence of B compound and become active only when the B compound is absent.

Thus, the answer is repressor and repressible.

The answer is a repressive mutation (the term is similar to b option).

Explanation:

In bacteria, the arginine regulon consists of a dozen genes required during the transport and biosynthesis of arginine (arg genes), these genes are controlled as a single unit. In prokaryotes, the concept of regulon is similar to the operon; however, an operon is composed of a group of genes linearly localized on bacterial chromosome, while a regulon can be formed by genes localized in different chromosome regions. Moreover, in eukaryotes, this concept is also used in order to indicate a set of linked genes that are regulated by the same regulatory gene sequence. A repressive mutation in a positive regulator of the arg regulon may trigger the inhibition of arg genes by affecting their ability to bind arginine.

The answer is negative inducible and positive repressible. This is because, since the gene is constitutive, it is always transcribed unless repressed. It is also structural because it codes for enzymes or proteins that are non-regulatory. The fact that transcription factors cannot bind to the promoter means it cannot be transcribed (hence also repressed by the mutation).

both types of regulatory systems have promoter and operator reegulatory sequences. both types of regulaory systems use allostery in regulating transcription

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