Molecular Biology: Gene Expression
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Questions and Answers

What is the primary function of RNA splicing in cells?

  • To produce tRNA
  • To produce rRNA
  • To produce miRNA
  • To produce mRNA (correct)
  • What is the primary function of elongation factors associated with RNA polymerase?

  • To increase the speed of RNA synthesis
  • To initiate transcription by binding to the promoter region
  • To proofread and edit the RNA transcript
  • To decrease the likelihood of RNA polymerase dissociation before reaching the end of a gene (correct)
  • What is the term given to the RNA after 5ʹ- and 3ʹ-end processing and splicing have taken place?

  • pre-mRNA
  • tRNA
  • mRNA (correct)
  • rRNA
  • What is the role of ATP-dependent chromatin remodeling complexes in eukaryotic transcription?

    <p>To move or rescue stalled RNA polymerase</p> Signup and view all the answers

    What is the byproduct of the splicing event that is removed from the exons?

    <p>Intron</p> Signup and view all the answers

    What is the function of histone chaperones in eukaryotic transcription?

    <p>To partially disassemble nucleosomes in front of RNA polymerase</p> Signup and view all the answers

    How many RNA molecules are involved in the machinery that catalyzes pre-mRNA splicing?

    <p>Five</p> Signup and view all the answers

    What is the difference between the 5' and 3' ends of a bacterial mRNA compared to a eukaryotic mRNA?

    <p>Eukaryotic mRNA has a 5' cap and poly-A tail, while bacterial mRNA does not</p> Signup and view all the answers

    What is the energy source required for the splicing event?

    <p>ATP</p> Signup and view all the answers

    What is the purpose of the 5' cap and poly-A tail in eukaryotic mRNA?

    <p>To increase the stability of the RNA transcript</p> Signup and view all the answers

    What is the first step in the splicing event?

    <p>First transesterification</p> Signup and view all the answers

    What is the result of the first transesterification reaction?

    <p>Formation of a lariat</p> Signup and view all the answers

    What is the primary difference between transcription in prokaryotes and eukaryotes?

    <p>Eukaryotes have chromatin structure, while prokaryotes do not</p> Signup and view all the answers

    What is the relationship between transcription and RNA processing in eukaryotes?

    <p>Transcription is the first step in producing a mature mRNA</p> Signup and view all the answers

    Why is RNA splicing necessary despite the removal of large numbers of introns?

    <p>To ensure accurate splicing and deal with the enormous variety of introns</p> Signup and view all the answers

    What is the result of RNA splicing in eukaryotes?

    <p>The formation of a mature mRNA molecule</p> Signup and view all the answers

    What is the primary role of RNA in the flow of genetic information in cells?

    <p>To transcribe DNA sequences into a usable form</p> Signup and view all the answers

    What is the term used to describe the fundamental principle of genetic information flow in cells?

    <p>Central dogma of molecular biology</p> Signup and view all the answers

    What is the name of the process by which the nucleotide sequence of a portion of DNA is copied into RNA?

    <p>Transcription</p> Signup and view all the answers

    What is the term used to describe the functional RNAs that fold into precise three-dimensional structures?

    <p>Structural RNA</p> Signup and view all the answers

    What is the characteristic feature of genomes in most multicellular organisms?

    <p>Surprisingly disorderly</p> Signup and view all the answers

    What is the term used to describe the short sequences of DNA that code for protein?

    <p>Exons</p> Signup and view all the answers

    What is the term used to describe the large blocks of seemingly meaningless DNA?

    <p>Introns</p> Signup and view all the answers

    What is the current understanding of the roles of many non-coding RNAs?

    <p>Their roles are not yet fully understood</p> Signup and view all the answers

    What is a common characteristic of protein-coding genes and their locations on chromosomes?

    <p>They are often located on different chromosomes.</p> Signup and view all the answers

    What percentage of the human genome is represented in Figure 6-2?

    <p>1/2000th</p> Signup and view all the answers

    What is indicated by the yellow triangles in Figure 6-2?

    <p>Positions where the human genome codes for a different amino acid than the Neanderthal genome.</p> Signup and view all the answers

    What can be inferred about the function of the Txtl1 gene?

    <p>It has undergone positive selection.</p> Signup and view all the answers

    What is the significance of the blue histogram in Figure 6-2?

    <p>It indicates the extent to which portions of the human genome are conserved with other vertebrate species.</p> Signup and view all the answers

    What can be said about the proteins encoded by the genes in Figure 6-2?

    <p>Most of them are identical between humans and Neanderthals.</p> Signup and view all the answers

    What is a likely scenario regarding the regions between the genes in Figure 6-2?

    <p>They may contain additional, currently unrecognized genes.</p> Signup and view all the answers

    How many genes for non-coding RNAs are present in Figure 6-2?

    <p>6</p> Signup and view all the answers

    What is unique about eukaryotic mRNAs compared to bacterial mRNAs?

    <p>They nearly always contain the information for only a single protein</p> Signup and view all the answers

    What is the role of the CTD in eukaryotic RNA polymerase II?

    <p>To recruit mRNA processing factors</p> Signup and view all the answers

    What is the significance of phosphorylation of the CTD in eukaryotic RNA polymerase II?

    <p>It recruits 5' capping enzymes</p> Signup and view all the answers

    Why do genes transcribed by RNA Pol I and RNA Pol III not have capped 5' ends?

    <p>Because they do not have a CTD</p> Signup and view all the answers

    What is the purpose of the RNA-processing proteins carried by RNA polymerase II?

    <p>To act on the newly synthesized RNA as it emerges from the RNA polymerase</p> Signup and view all the answers

    Which RNA-processing enzymes do not travel with the polymerase?

    <p>Most RNA-processing enzymes</p> Signup and view all the answers

    What is the role of the few critical components carried by the RNA polymerase II tail for RNA splicing?

    <p>To serve as a nucleation site for the remaining components</p> Signup and view all the answers

    What is the result of the phosphorylation of the CTD in eukaryotic RNA polymerase II?

    <p>Recruitment of 5' capping enzymes</p> Signup and view all the answers

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