if you want to remove an article from website contact us from top.

    what occurs when an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor?

    James

    Guys, does anyone know the answer?

    get what occurs when an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor? from EN Bilgi.

    Solved What occurs when an inducer is added to a medium

    Answer to Solved What occurs when an inducer is added to a medium

    Skip to main content

    Question: What Occurs When An Inducer Is Added To A Medium Containing An Organism With A Metabolic Pathway Controlled By A Repressor? A. The Inducer Combines With The Repressor And Causes The Repressor To Bind To DNA B. The Inducer Combines With The Repressor And Causes The Repressor To Dissociate DNA C. The Inducer Combines With The Substrate And Blocks Induction D.

    Show transcribed image text

    Expert Answer

    iii-a the correct option is option B. this situation is same as that of Lac operon. In Lac operon lactose binds to repressor which leads to the dissociation of repressor from…

    View the full answer

    Transcribed image text: What occurs when an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor? A. The inducer combines with the repressor and causes the repressor to bind to DNA B. The inducer combines with the repressor and causes the repressor to dissociate DNA C. The inducer combines with the substrate and blocks induction D. The inducer combines with the substrate and activates induction E. The inducer does not combine with repressor but functions as a chaperone molecule for the enzyme-substrate complex The influenza reassortment process is enhanced by a particular feature of the virus, __ namely, the genome. A. linear B. circular C. double-stranded D. single-stranded E. segmented HIV-infected individuals who are fast progressors (progress quickly to AIDS) will have relatively __ viral loads and a relatively __ decline in the number of circulating CD4-positive cells compared to individuals who are slow progressors. A. -high -/-rapid- B. -high -/-slow- C. -low -/-rapid- D. -low-/-slow- E. none of the above The HIV provirus is transcribed by __ to produce viral mRNAs. A. RNA polymerase II B. the viral reverse transcriptase C. an HIV-encoded RNA polymerase D. a virion-associated RNA-dependent RNA replicase E. none of the above The AraC protein can act either as a repressor or an activator, depending on the conformation that the protein assumes after binding arabinose. The binding of arabinose to AraC: A Causes a conformational change that allows AraC to bind to DNA. B. Causes a conformational change that prevents AraC from binding to DNA. C. Causes a conformational change that causes AraC to dimerize. D. Causes a conformational change that prevents AraC from dimerizing. E. Causes AraC to bind to operator sites that position it in a manner that promotes transcription. Which of the following explains the regulatory activity of sRNA? A. It codes for an anti- sigma factor. B. It prevents CRP interaction with RNA polymerase, thereby blocking its access to the promoter. C. It synthesizes ppGpp. D. It targets mRNAs for degradation. E. It creates an attenuator stem loop.

    © 2003-2022 Chegg Inc. All rights reserved.

    Source : www.chegg.com

    Chapter 8: Metabolic Regulation Flashcards

    Start studying Chapter 8: Metabolic Regulation. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

    Chapter 8: Metabolic Regulation

    47 studiers in the last day

    Regulation of an enzyme's activity occurs

    A) transcriptionally.

    B) translationally.

    C) posttranslationally.

    D) at any point on the enzymatic production pathway.

    Click card to see definition 👆

    C

    Click again to see term 👆

    Allosteric enzymes have two important binding sites. These are the

    A) active site and the allosteric(变构) site.

    B) active site and the inhibitory site.

    C) allosteric site and the effector site.

    D) allosteric site and the passive site.

    Click card to see definition 👆

    A

    Click again to see term 👆

    1/28 Created by Caro609

    Terms in this set (28)

    Regulation of an enzyme's activity occurs

    A) transcriptionally.

    B) translationally.

    C) posttranslationally.

    D) at any point on the enzymatic production pathway.

    C

    Allosteric enzymes have two important binding sites. These are the

    A) active site and the allosteric(变构) site.

    B) active site and the inhibitory site.

    C) allosteric site and the effector site.

    D) allosteric site and the passive site.

    A

    Feedback inhibition mutants can be used for the large scale commercial production of which compound?

    A) Glycolipids B) Amino acids C) Antibiotics D) Lipoproteins B

    Covalent modification of an enzyme often includes the

    A) addition or deletion of some small organic molecule.

    B) binding of the enzyme to specific cytoplasmic ribosomes.

    C) rearrangement of the components of the enzyme proper.

    D) none of the above.

    A

    When amino acids such as arginine and proline bind to an enzyme, they

    A) increase the efficiency of the enzyme.

    B) inhibit the enzyme.

    C) reconfigure the enzyme so that it becomes functional.

    D) extend the functional life of the enzyme.

    B

    Certain proteins, known as regulatory proteins,

    A) are influenced by small molecules.

    B) bind to specific DNA sites.

    C) regulate transcription.

    D) all of the above.

    D

    Histones are __________ so they combine strongly and relatively nonspecifically with __________ DNA.

    A) positively charged / negatively charged

    B) negatively charged / positively charged

    C) neutral / negatively charged

    D) positively charged / neutral

    A

    A key site for the binding of protein with the DNA molecule is the

    A) major groove. B) minor groove. C) histone complex.

    D) primary supercoil.

    A

    When considering the biological information flow, transcription is usually thought of as the

    A) first step. B) second step. C) third step.

    D) only step because everything else flows from transcription.

    A

    Arginine in the culture medium

    A) enhances the synthesis of the enzymes required for the production of arginine.

    B) represses the synthesis of the enzymes required for the production of arginine.

    C) neutralizes the enzymes required for the production of arginine.

    D) has no effect on the enzymes required for the production of arginine

    B

    Enzyme induction occurs

    A) when the substrate is present.

    B) when the organism is environmentally stressed.

    C) continuously.

    D) when the substrate is depleted.

    A

    In enzyme induction, the substance that represses enzyme production is called a(n)

    A) inducer. B) repressor. C) corepressor. D) effector. C

    Enzyme repression or induction acts at the level of

    A) pre-transcription.

    B) transcription. C) translation.

    D) post-translation.

    B

    What occurs when an inducer is added to a medium containing an organism with a metabolic pathway controlled by a repressor?

    A) The inducer combines with the repressor and activates it.

    B) The inducer combines with the repressor and inactivates it.

    C) The inducer combines with the substrate and blocks induction.

    D) The inducer does not combine with but functions as a chaperone molecule for the enzyme-substrate complex.

    B

    In the tryptophan operon, synthesis of the leader peptide results in

    A) termination of transcription of the remainder of the trp operon.

    B) initiation of transcription of the tryptophan structural genes.

    C) augmentation of transcription of the tryptophan structural genes.

    D) none of the above.

    A

    A group of genes responding to a common regulatory protein is called a(n) __________ and a group of genes responding to the same environmental stimulus is called a(n) __________.

    A) stimulon / modulon

    B) modulon / operon

    C) operon / stimulon

    D) modulon / stimulon

    D

    Cyclic AMP is synthesized from ATP by an enzyme called

    A) adenylate cyclase.

    B) catabolite activator protein (CAP) activase.

    C) cAMP receptor protein (CRP) receptase.

    D) RNA polymerase. A

    How does the presence of an inducer affect transcription?

    A) The inducer binds to the operator.

    B) The inducer does not bind to the operator.

    C) The inducer causes the repressor to bind to the operator.

    D) The inducer prevents the repressor from binding to the operator.

    D

    The amount of alternative sigma factor in the cell regulates the

    Source : quizlet.com

    The lac operon (article)

    Regulation of genes for lactose utilization. lac repressor, catabolite activator protein, and cAMP.

    Regulation of gene expression and cell specialization

    The lac operon

    Regulation of genes for lactose utilization. lac repressor, catabolite activator protein, and cAMP.

    Google ClassroomFacebookTwitter

    Email

    Key points:

    The lac operon of E. coli contains genes involved in lactose metabolism. It's expressed only when lactose is present and glucose is absent.

    Two regulators turn the operon "on" and "off" in response to lactose and glucose levels: the lac repressor and catabolite activator protein (CAP).

    The lac repressor acts as a lactose sensor. It normally blocks transcription of the operon, but stops acting as a repressor when lactose is present. The lac repressor senses lactose indirectly, through its isomer allolactose.

    Catabolite activator protein (CAP) acts as a glucose sensor. It activates transcription of the operon, but only when glucose levels are low. CAP senses glucose indirectly, through the "hunger signal" molecule cAMP.

    Introduction

    Lactose: it's what's for dinner! While that may not sound delicious to us (lactose is the main sugar in milk, and you probably don't want to eat it plain), lactose can be an excellent meal for E. coli bacteria. However, they'll only gobble up lactose when other, better sugars – like glucose – are unavailable.

    With that for context, what exactly is the lac operon? The lac operon is an operon, or group of genes with a single promoter (transcribed as a single mRNA). The genes in the operon encode proteins that allow the bacteria to use lactose as an energy source.

    What makes the lac operon turn on?

    E. coli bacteria can break down lactose, but it's not their favorite fuel. If glucose is around, they would much rather use that. Glucose requires fewer steps and less energy to break down than lactose. However, if lactose is the only sugar available, the E. coli will go right ahead and use it as an energy source.

    To use lactose, the bacteria must express the lac operon genes, which encode key enzymes for lactose uptake and metabolism. To be as efficient as possible, E. coli should express the lac operon only when two conditions are met:

    Lactose is available, and

    Glucose is not available

    How are levels of lactose and glucose detected, and how how do changes in levels affect lac operon transcription? Two regulatory proteins are involved:

    One, the lac repressor, acts as a lactose sensor.

    The other, catabolite activator protein (CAP), acts as a glucose sensor.

    These proteins bind to the DNA of the lac operon and regulate its transcription based on lactose and glucose levels. Let's take a look at how this works.

    Structure of the lac operon

    The lac operon contains three genes: lacZ, lacY, and lacA. These genes are transcribed as a single mRNA, under control of one promoter.

    Genes in the lac operon specify proteins that help the cell utilize lactose. lacZ encodes an enzyme that splits lactose into monosaccharides (single-unit sugars) that can be fed into glycolysis. Similarly, lacY encodes a membrane-embedded transporter that helps bring lactose into the cell. [More details]

    In addition to the three genes, the lac operon also contains a number of regulatory DNA sequences. These are regions of DNA to which particular regulatory proteins can bind, controlling transcription of the operon.

    Structure of the lac operon. The DNA of the lac operon contains (in order from left to right): CAP binding site, promoter (RNA polymerase binding site), operator (which overlaps with promoter), lacZ gene, lacY gene, and lacA gene. The activator protein CAP, when bound to a molecule called cAMP (discussed later), binds to the CAP binding site and promotes RNA polymerase binding to the promoter. The lac repressor protein binds to the operator and blocks RNA polymerase from binding to the promoter and transcribing the operon.

    _Image modified from "Prokaryotic gene regulation: Figure 3," by OpenStax College, Biology (CC BY 4.0)._

    The promoter is the binding site for RNA polymerase, the enzyme that performs transcription.

    The operator is a negative regulatory site bound by the lac repressor protein. The operator overlaps with the promoter, and when the lac repressor is bound, RNA polymerase cannot bind to the promoter and start transcription.

    The CAP binding site is a positive regulatory site that is bound by catabolite activator protein (CAP). When CAP is bound to this site, it promotes transcription by helping RNA polymerase bind to the promoter.

    Let's take a closer look at the lac repressor and CAP and their roles in regulation of the lac operon.

    The lac repressor

    The lac repressor is a protein that represses (inhibits) transcription of the lac operon. It does this by binding to the operator, which partially overlaps with the promoter. When bound, the lac repressor gets in RNA polymerase's way and keeps it from transcribing the operon. [Where does the lac repressor come from?]

    When lactose is not available, the lac repressor binds tightly to the operator, preventing transcription by RNA polymerase. However, when lactose is present, the lac repressor loses its ability to bind DNA. It floats off the operator, clearing the way for RNA polymerase to transcribe the operon.

    Source : www.khanacademy.org

    Do you want to see answer or more ?
    James 6 month ago
    4

    Guys, does anyone know the answer?

    Click For Answer