Quiz 1: Regulation Of Transcription In Prokaryote

Reviewed by Editorial Team
The ProProfs editorial team is comprised of experienced subject matter experts. They've collectively created over 10,000 quizzes and lessons, serving over 100 million users. Our team includes in-house content moderators and subject matter experts, as well as a global network of rigorously trained contributors. All adhere to our comprehensive editorial guidelines, ensuring the delivery of high-quality content.
Learn about Our Editorial Process
| By Biomolfa
B
Biomolfa
Community Contributor
Quizzes Created: 6 | Total Attempts: 14,249
| Attempts: 2,436
SettingsSettings
Please wait...
  • 1/10 Questions

    Control of gene expression by preventing a gene from being expressed.

    • Transcription
    • Induction
    • Translation
    • Replication
    • Repression
Please wait...
About This Quiz

Each question below contains fivesuggestedresponses. Please choose by clicking the one best response to each question.
TOPICS: Regulation of Transcription in Prokaryote

The QUIZ is for the SERIOUS STUDENTS only

Quiz 1: Regulation Of Transcription In Prokaryote - Quiz

Quiz Preview

  • 2. 

    DNA sequence(s) lying upstream from a gene, to which RNA polymerase binds.

    • Promoter

    • Operon

    • Regulator

    • Operator

    • Repressor

    Correct Answer
    A. Promoter
    Explanation
    A promoter is a DNA sequence that is located upstream from a gene and serves as the binding site for RNA polymerase. RNA polymerase is an enzyme responsible for initiating the transcription process, where a complementary RNA molecule is synthesized from the DNA template. The promoter region plays a crucial role in gene regulation by determining when and how often a gene is transcribed. By binding to the promoter, RNA polymerase helps to initiate the transcription process and allows for the expression of the gene.

    Rate this question:

  • 3. 

    A mRNA molecule that yields two or more proteins.

    • Promoter

    • Operon

    • Polycistronic

    • Operator

    • Regulator

    Correct Answer
    A. Polycistronic
    Explanation
    Polycistronic refers to an mRNA molecule that contains multiple coding regions, or open reading frames (ORFs), which can be translated into two or more proteins. In polycistronic mRNA, the coding regions are typically separated by short non-coding regions called intercistronic regions. This arrangement allows for the coordinated expression of multiple genes in prokaryotes, where several genes involved in a common function are transcribed together as a single mRNA molecule. This enables efficient regulation and simultaneous production of multiple proteins that work together in a specific pathway or process.

    Rate this question:

  • 4. 

    Which of the following gene for beta-galactosidase.

    • LacZ

    • LacY

    • LacA

    • LacZY

    • LacZYA

    Correct Answer
    A. LacZ
    Explanation
    The correct answer is lacZ because it is the gene that encodes for beta-galactosidase. Beta-galactosidase is an enzyme that is involved in the breakdown of lactose into glucose and galactose. The lacZ gene is part of the lac operon in E. coli and is responsible for the production of beta-galactosidase, which allows the bacteria to utilize lactose as a carbon source. The other options (lacY, lacA, lacZY, lacZYA) are not the specific gene for beta-galactosidase.

    Rate this question:

  • 5. 

    A group of linked genes whose expression is coordinately regulated.

    • Promoter

    • Operon

    • Regulator

    • Operator

    • Repressor

    Correct Answer
    A. Operon
    Explanation
    An operon is a group of linked genes whose expression is coordinately regulated. In an operon, multiple genes are transcribed together as a single mRNA molecule, allowing for efficient regulation of gene expression. The operon is controlled by a promoter, which initiates transcription, and an operator, which acts as a switch to turn gene expression on or off. The regulator and repressor proteins bind to the operator and regulate the expression of the operon by blocking or allowing transcription. Therefore, the correct answer is operon.

    Rate this question:

  • 6. 

    Region of an operon, close to the promoter, to which a repressor protein binds.

    • Promoter

    • Terminator

    • Regulator

    • Operator

    • Repressor

    Correct Answer
    A. Operator
    Explanation
    The operator is the region of an operon that is located close to the promoter and is responsible for binding to a repressor protein. This binding prevents the RNA polymerase from transcribing the genes in the operon, effectively turning off gene expression. The operator acts as a regulatory element that controls the expression of the operon by determining whether the genes are transcribed or not.

    Rate this question:

  • 7. 

    The trpE gene contains a 5’ untranslated region that plays an important role in the regulatory mechanism called ……………..

    • Co-repression

    • Operon

    • Repression

    • Expression

    • Attenuation

    Correct Answer
    A. Attenuation
    Explanation
    The trpE gene contains a 5’ untranslated region that plays an important role in the regulatory mechanism called attenuation. Attenuation is a process in gene regulation where the transcription of the gene is prematurely terminated. In the case of the trpE gene, the 5’ untranslated region can form specific secondary structures that can either allow or prevent the formation of a transcription termination hairpin. This mechanism controls the expression of the trpE gene based on the availability of tryptophan in the cell. When tryptophan levels are low, the ribosome stalls at the trp codons, allowing the formation of the transcription termination hairpin and resulting in attenuation of gene expression.

    Rate this question:

  • 8. 

    The attenuator hairpin is the product of the base pairing of sequences ________

    • 1 and 4

    • 2 and 4

    • 3 and 4

    • 1 and 2

    • 1 and 3

    Correct Answer
    A. 3 and 4
    Explanation
    The correct answer is 3 and 4. The attenuator hairpin is formed by the base pairing of sequences 3 and 4.

    Rate this question:

  • 9. 

    Tryptophan, the end-product of the enzymes encoded by the trp operon, therefore acts as ________

    • A promoter

    • A co-repressor

    • A repressor

    • An inducer

    • A terminator

    Correct Answer
    A. A co-repressor
    Explanation
    Tryptophan, as the end-product of the enzymes encoded by the trp operon, acts as a co-repressor. This means that when tryptophan levels are high, it binds to the repressor protein and together they bind to the operator region of the operon. This binding prevents RNA polymerase from transcribing the genes in the operon, effectively shutting down the production of tryptophan. Therefore, tryptophan acts as a co-repressor, working in conjunction with the repressor to regulate the expression of the trp operon.

    Rate this question:

  • 10. 

    A sugar, that is the true inducer of the lac operon.

    • Monosacharide

    • Lactose

    • Galactose

    • Glucose

    • Allolactose

    Correct Answer
    A. Allolactose
    Explanation
    Allolactose is the correct answer because it is a sugar molecule that acts as an inducer for the lac operon. The lac operon is a group of genes involved in lactose metabolism in bacteria. When lactose is present in the environment, it is converted into allolactose, which binds to the lac repressor protein and prevents it from binding to the lac operator. This allows RNA polymerase to bind to the promoter and transcribe the genes involved in lactose metabolism. Therefore, allolactose is the true inducer of the lac operon.

    Rate this question:

Quiz Review Timeline (Updated): Mar 22, 2023 +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Mar 22, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • May 02, 2010
    Quiz Created by
    Biomolfa
Back to Top Back to top
Advertisement
×

Wait!
Here's an interesting quiz for you.

We have other quizzes matching your interest.