Bio1334 Genetics - Molecular Genetics - Control Of Gene Expression (Lectures Six And Seven)

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  • 1/22 Questions

    Name one of the Cis-acting regulatory regions.

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About This Quiz

Demonstrate an overview of the principles of control of gene expression in eukaryotes Demonstrate an outline understanding of transcriptional control in eukaryotes Demonstrate appreciation of differences in gene expression in bacteria and control of gene expression in bacteria

Bio1334 Genetics - Molecular Genetics - Control Of Gene Expression (Lectures Six And Seven) - Quiz

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  • 2. 

    True or False?An operon of a bacterial cell (cluster of related genes) has one promoter, thus all genes in an operon are transcribed together.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    In a bacterial operon, all the genes are transcribed together as they are controlled by a single promoter. The promoter region is responsible for initiating the transcription process by binding to RNA polymerase. Once the RNA polymerase is bound to the promoter, it transcribes all the genes present in the operon as a single mRNA molecule. This allows for coordinated regulation of gene expression, as all the genes within the operon are transcribed simultaneously and can be regulated as a unit. Therefore, the statement "An operon of a bacterial cell has one promoter, thus all genes in an operon are transcribed together" is true.

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  • 3. 

    True or False:Single pre-mRNAs can produce multiple products through alternative splicing.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Alternative splicing is a process in which different combinations of exons are joined together during mRNA processing, resulting in the production of multiple mRNA isoforms from a single pre-mRNA. This allows for the generation of different protein products from the same gene. Therefore, the statement "Single pre-mRNAs can produce multiple products through alternative splicing" is true.

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  • 4. 

    Complete the following sentence:In bacterial cells, genes of related function are often clustered into ____________.

    Correct Answer
    Operons
    Explanation
    In bacterial cells, genes of related function are often clustered into operons. Operons are functional units of DNA that consist of multiple genes that are transcribed together as a single mRNA molecule. This allows for coordinated regulation and expression of genes involved in a specific biological process or pathway. The genes within an operon are typically under the control of a single promoter region and are transcribed as a polycistronic mRNA, which means that multiple genes are translated from the same mRNA molecule. Operons are commonly found in prokaryotes and are essential for efficient gene regulation and expression in bacterial cells.

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  • 5. 

    Which of the following is the correct term for transgenics?

    • Genes between species

    • More than one gene

    • Two different alleles

    Correct Answer
    A. Genes between species
    Explanation
    Transgenics refers to the process of transferring genes between different species. This involves the introduction of genetic material from one organism into another, resulting in an organism that carries genes from both species. Therefore, the correct term for transgenics is "genes between species".

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  • 6. 

    Fill in the blank:Injecting double stranded RNA reduces expression of specific genes by reducing levels of mRNA. This is known as RNA ___________ and is sequence specific.

    Correct Answer
    Interference
    Explanation
    Injecting double stranded RNA into a cell leads to a process called RNA interference. This process specifically targets and reduces the expression of certain genes by decreasing the levels of messenger RNA (mRNA). RNA interference is a sequence-specific mechanism, meaning it can selectively silence genes with complementary sequences to the injected double stranded RNA.

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  • 7. 

    Which form of small RNAs can also control gene expression?

    Correct Answer
    Micro
    Micro RNA
    Micro RNAS
    miRNA
    miRNAs
    Explanation
    MicroRNAs (miRNAs) are a form of small RNAs that can control gene expression. They are short RNA molecules that bind to messenger RNA (mRNA), preventing it from being translated into protein or marking it for degradation. This regulation of gene expression by miRNAs plays a crucial role in various biological processes, including development, cell differentiation, and disease progression. Therefore, all the options provided (Micro, Micro RNA, Micro RNAS, miRNA, miRNAs) can control gene expression through the action of miRNAs.

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  • 8. 

    Complete the following sentence:Core histone proteins can also be covalently modified on their ___________________.

    Correct Answer
    N-terminal tails
    N terminal tails
    N-terminal tail
    N terminal tail
    Explanation
    The correct answer is N-terminal tails, N terminal tails, N-terminal tail, N terminal tail. The N-terminal tails of core histone proteins can undergo covalent modifications. These modifications, such as acetylation, methylation, phosphorylation, and ubiquitination, can affect the structure and function of chromatin, leading to changes in gene expression and various cellular processes.

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  • 9. 

    Name the protein that binds to miRNA and mRNA in gene expression.

    Correct Answer
    Argonaute
    Explanation
    Argonaute is the protein that binds to miRNA and mRNA in gene expression. It plays a crucial role in the RNA interference pathway, where it guides the miRNA to the target mRNA, leading to the degradation of the mRNA or inhibition of its translation. Argonaute proteins are essential for regulating gene expression and are found in various organisms, including humans. They are known for their role in post-transcriptional gene silencing and are key players in many biological processes, including development, immune response, and disease.

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  • 10. 

    Fill in the blank:Transcription begins at the _______________, found within the promoter region.

    Correct Answer
    Initiation site
    Explanation
    The initiation site is where transcription begins within the promoter region. It is the specific location on the DNA where RNA polymerase binds and starts the process of transcribing the DNA into RNA. This site serves as a starting point for the assembly of the transcription complex and the subsequent synthesis of RNA molecules.

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  • 11. 

    Which of the following is the role of trans-acting proteins?

    • Bind to promoter and enhancer to control transcription from the gene

    • Bind to promoter to initiate transcription

    • Bind to promoter and enhancer to control translation from the gene

    Correct Answer
    A. Bind to promoter and enhancer to control transcription from the gene
    Explanation
    Trans-acting proteins play a crucial role in gene regulation by binding to both the promoter and enhancer regions of a gene. This binding allows them to control the process of transcription, which is the synthesis of RNA from DNA. By interacting with these regulatory regions, trans-acting proteins can either enhance or repress the transcription of a gene, thereby influencing the expression of specific traits or functions. Their ability to bind to both the promoter and enhancer regions enables them to coordinate and fine-tune the transcriptional activity of genes in response to various cellular signals and environmental cues.

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  • 12. 

    What is the function of Lac repressor in bacterial gene expression?

    • It blocks transcription of the lac operon in the absence of lactose

    • It activates transcription of the lac operon in the absence of lactose

    • It blocks transcription of the lac operon in the presence of lactose

    • It activates transcription of the lac operon in the presence of lactose

    Correct Answer
    A. It blocks transcription of the lac operon in the absence of lactose
    Explanation
    The Lac repressor is a protein that binds to the operator region of the lac operon in the absence of lactose. This binding prevents RNA polymerase from binding to the promoter and initiating transcription of the lac operon genes. Therefore, the Lac repressor blocks transcription of the lac operon in the absence of lactose.

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  • 13. 

    Which of the following inhibits RNA polymerase II?

    • α-amanitin

    • β-amanitin

    • α-polymerase

    • β-polymerase

    Correct Answer
    A. α-amanitin
    Explanation
    α-amanitin is a potent inhibitor of RNA polymerase II, which is responsible for transcribing mRNA in eukaryotic cells. It binds to the active site of RNA polymerase II and prevents the enzyme from synthesizing RNA. This inhibition disrupts the process of gene expression and ultimately leads to cell death. β-amanitin, on the other hand, inhibits RNA polymerase II in bacteria, not eukaryotes. α-polymerase and β-polymerase are not known inhibitors of RNA polymerase II.

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  • 14. 

    How does the structure of chromatin aid eukaryotic gene regulation?

    • By providing a "brake" on runaway basal transcription

    • Its tight packaging does not allow all genes to be expressed

    • Providing the perfect shape for basal transcription

    Correct Answer
    A. By providing a "brake" on runaway basal transcription
    Explanation
    The structure of chromatin aids eukaryotic gene regulation by providing a "brake" on runaway basal transcription. This means that the tight packaging of chromatin prevents all genes from being expressed at once, allowing for more precise control over gene expression. This regulation is essential for maintaining the proper functioning of cells and ensuring that genes are only expressed when needed.

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  • 15. 

    Complete this sentence:_________ proteins bound to enhancers interact with the basal transcription complex.

    Correct Answer
    N/A
  • 16. 

    Check the options below that can control mRNA stability and mRNA translation.

    • UTRs (untranslated regions)

    • Double stranded RNAs

    • Single stranded RNAs

    • SnRNAs

    Correct Answer(s)
    A. UTRs (untranslated regions)
    A. Double stranded RNAs
    Explanation
    UTRs (untranslated regions) are segments of mRNA that do not code for proteins but play a crucial role in controlling mRNA stability and translation. They contain regulatory elements that can influence the binding of proteins and other molecules involved in mRNA degradation and translation. Double stranded RNAs can also control mRNA stability and translation by triggering RNA interference, a process where small RNA molecules bind to mRNA and prevent its translation. Single stranded RNAs and snRNAs, on the other hand, are not directly involved in controlling mRNA stability and translation.

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  • 17. 

    What happens during alternative splicing of pre-mRNAs?

    • Exons are targeted for removal in different combinations

    • Introns are targeted for removal in different combinations

    • Specific exons are removed

    • Specific introns are removed

    Correct Answer
    A. Exons are targeted for removal in different combinations
    Explanation
    During alternative splicing of pre-mRNAs, exons are targeted for removal in different combinations. This process allows for the production of multiple mRNA transcripts from a single gene by selectively removing certain exons and joining the remaining exons together. This alternative splicing mechanism contributes to the diversity of proteins that can be generated from a limited number of genes, as different combinations of exons can result in different protein isoforms with distinct functions or properties.

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  • 18. 

    Within gene sequences, introns can occur in:

    • The 5′ untranslated region (UTR), and the 3′ UTR

    • The 5′ UTR, the protein coding region, and the 3′ UTR

    • The coding region

    • The promoter, the 5′ UTR, the protein coding region, and the 3′ UTR

    Correct Answer
    A. The 5′ untranslated region (UTR), and the 3′ UTR
    Explanation
    Introns are non-coding regions within a gene sequence that are transcribed into RNA but are not translated into protein. The 5′ untranslated region (UTR) and the 3′ UTR are both regions that occur before and after the protein coding region. Therefore, introns can occur in these regions, as mentioned in the correct answer. The coding region, on the other hand, consists of exons, which are the coding sequences that are eventually translated into protein. The promoter is not a part of the gene sequence itself but is a region that controls the initiation of gene transcription. Therefore, introns do not occur in the promoter region.

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  • Mar 20, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Nov 04, 2015
    Quiz Created by
    Elly Crook
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