T.10 La transcripción en eucariotas: panorama global / La RNA Pol II
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Questions and Answers

What is the main difference between transcription in eukaryotes and bacteria?

  • The genetic material is located in the nucleus in eukaryotes (correct)
  • Eukaryotes have a faster transcription process
  • Eukaryotes have more complex RNA polymerases
  • Bacteria have more RNA polymerases than eukaryotes

    • What is the function of the 3 RNA polymerases in the nucleus?

  • To synthesize proteins
  • To replicate the DNA
  • To transcribe the genetic information (correct)
  • To catalyze the translation process

    • What happens to the transcripts produced in the nucleus?

  • They are stored in the nucleolus
  • They are degraded immediately
  • They are transported to the cytoplasm for translation (correct)
  • They are translated into proteins in the nucleus

    • What is unique about the RNA polymerases found in mitochondria and chloroplasts?

    <p>They are similar to those found in bacteria</p> Signup and view all the answers

    What is the effect of chromatin organization on transcription?

    <p>It exercises a negative control over transcription</p> Signup and view all the answers

    What is a characteristic of archaea in terms of their transcription process?

    <p>Their transcription process is similar to that of eukaryotes</p> Signup and view all the answers

    What type of control is commonly used in prokaryotes?

    <p>Negative control</p> Signup and view all the answers

    What is the main difference between eukaryotic and prokaryotic genomes?

    <p>Eukaryotic genomes have more non-coding DNA</p> Signup and view all the answers

    What is the function of general transcription factors (GTF)?

    <p>To initiate transcription</p> Signup and view all the answers

    What is the result of RNA polymerase moving along the DNA?

    <p>Supercoiling of DNA</p> Signup and view all the answers

    What is the function of chromatin remodelers?

    <p>To move nucleosomes</p> Signup and view all the answers

    How many RNA polymerases are found in eukaryotes?

    <p>7</p> Signup and view all the answers

    What is the function of RNA Pol IV and RNA Pol V in plants?

    <p>To regulate gene expression</p> Signup and view all the answers

    What is the name of the structure formed by the RNA Pol I transcript?

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

    What is the significance of the linker sequences in chromatin?

    <p>They are inaccessible to transcription factors</p> Signup and view all the answers

    What is the result of the interaction between chromatin and transcription?

    <p>Mutual influence on each other</p> Signup and view all the answers

    Which RNA polymerase transcribes the majority of genes?

    <p>RNA Pol II</p> Signup and view all the answers

    What is the main function of RNA Pol III?

    <p>To transcribe tRNAs</p> Signup and view all the answers

    How many subunits make up the core of eukaryotic RNA polymerases?

    <p>10 subunits</p> Signup and view all the answers

    What is the name of the subcomplex found in RNA Pol II, but not in RNA Pol I and III?

    <p>Rpb4/Rpb7</p> Signup and view all the answers

    Which RNA polymerase has a unique trimeric subcomplex?

    <p>RNA Pol III</p> Signup and view all the answers

    What is the proposed evolutionary origin of RNA Pol I and III?

    <p>They evolved from RNA Pol II</p> Signup and view all the answers

    What is the name of the transcription factor that is similar to the C82/C34/C31 trimer in RNA Pol III?

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

    How many genes are transcribed by RNA Pol II?

    <p>Between 5,000 to 50,000</p> Signup and view all the answers

    What is the name of the subunit shared by RNA Pol I and III, but not by RNA Pol II?

    <p>AC19</p> Signup and view all the answers

    What is the structure of the RNA polymerase in bacteria?

    <p>A hand-like structure</p> Signup and view all the answers

    What is the primary reason why RNA Pol I consumes a significant amount of NTPs in the cell?

    <p>It transcribes multiple copies of the same gene that are repeated in the chromosomes.</p> Signup and view all the answers

    What is the main difference between the structure of RNA polymerases in bacteria and eukaryotes?

    <p>The length of the domains is different.</p> Signup and view all the answers

    How many subunits does the RNA Pol II of eukaryotes have?

    <p>12</p> Signup and view all the answers

    What is the function of the C17/C25 subcomplex in the RNA Pol III of eukaryotes?

    <p>The function is unknown.</p> Signup and view all the answers

    What is the primary function of RNA Pol III in eukaryotes?

    <p>It transcribes tRNAs, rRNA 5S, and other small RNAs.</p> Signup and view all the answers

    How do the RNA polymerases of eukaryotes and archaea differ in terms of their complexity?

    <p>Eukaryotic RNA polymerases are more complex.</p> Signup and view all the answers

    What is the effect of α-amanitina on RNA polymerases?

    <p>It blocks the movement of RNA Pol II.</p> Signup and view all the answers

    What is the main reason why RNA Pol II transcribes molecules of intermediate size?

    <p>Because it transcribes a wide variety of RNA molecules.</p> Signup and view all the answers

    How many RNA polymerases are present in the first eukaryote?

    <p>3</p> Signup and view all the answers

    What is the primary difference between RNA Pol I and RNA Pol III in terms of the length of the RNA molecules they transcribe?

    <p>RNA Pol I transcribes longer molecules.</p> Signup and view all the answers

    What is the function of the C-terminal domain (CTD) of the Rpb1 subunit in RNA Pol II?

    <p>To regulate the transcription process</p> Signup and view all the answers

    What is the location of the active center of RNA Pol II?

    <p>Between the Rpb1 and Rpb2 subunits</p> Signup and view all the answers

    What is the significance of the 'hand' structure in RNA Pol II?

    <p>It is a conserved structure in all polymerases</p> Signup and view all the answers

    What is the role of the accessory subunits in RNA Pol II?

    <p>To surround the large subunits</p> Signup and view all the answers

    Why is the Rpb4/Rpb7 dimer not always present in RNA Pol II?

    <p>It can enter and leave the enzyme</p> Signup and view all the answers

    What is the percentage of genes transcribed by RNA Pol II in eukaryotes?

    <p>20-40%</p> Signup and view all the answers

    What is unique about the subunit A12.2 in RNA Pol I?

    <p>It has functions of TFIIS and Rpb9</p> Signup and view all the answers

    What is the function of the trimeric subcomplex in RNA Pol III?

    <p>To initiate transcription rapidly</p> Signup and view all the answers

    What is the main difference between the subunit 1 of RNA Pol I and RNA Pol II?

    <p>The absence of a CTD domain</p> Signup and view all the answers

    What is the function of the subcomplex A49/A34.5 in RNA Pol I?

    <p>To initiate transcription</p> Signup and view all the answers

    What is the main difference between the structure of RNA Pol I and RNA Pol II?

    <p>The absence of a CTD domain</p> Signup and view all the answers

    What is the function of the subunit A190 in RNA Pol I?

    <p>To initiate transcription</p> Signup and view all the answers

    What is the main difference between the subunits 2 of RNA Pol I and RNA Pol II?

    <p>The similarity in their sequences</p> Signup and view all the answers

    What is the function of the trimeric subcomplex in RNA Pol I?

    <p>To help in the release of paused RNA polymerase</p> Signup and view all the answers

    What is the approximate angle of DNA bending during transcription by RNA Pol II?

    <p>90º</p> Signup and view all the answers

    Which part of the RNA Pol II complex is involved in selecting the transcription start site?

    <p>Rpb9</p> Signup and view all the answers

    What is the main difference between the subunits A49/A34.5 and A14/43?

    <p>Their function in transcription</p> Signup and view all the answers

    What is the function of the subunit A135 in RNA Pol I?

    <p>To interact with general transcription factors</p> Signup and view all the answers

    What is the primary function of the CTD domain of Rpb1?

    <p>Regulation of gene expression</p> Signup and view all the answers

    How many times is the conserved sequence of 7 amino acids repeated in the CTD domain of Rpb1 in mammals?

    <p>52</p> Signup and view all the answers

    What is the consequence of deleting more than half of the CTD repeats?

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

    What is the relationship between the length of the CTD domain and the complexity of the genome?

    <p>The length of CTD is directly proportional to the complexity of the genome</p> Signup and view all the answers

    Which amino acids in the CTD domain can be phosphorylated?

    <p>Tyr, Ser, and Thr</p> Signup and view all the answers

    What is the consequence of phosphorylating the CTD domain?

    <p>Recruitment of transcription factors</p> Signup and view all the answers

    What is the unique feature of the CTD domain in terms of its structure?

    <p>It is highly flexible and dynamic</p> Signup and view all the answers

    What is the primary difference between RNA Pol II and other RNA polymerases in terms of its subunit composition?

    <p>It has a smaller subunit composition</p> Signup and view all the answers

    What is the main reason for the high conservation of sequence among eukaryotic RNA polymerases, particularly in the catalytic domain?

    <p>The high degree of sequence conservation is necessary for the enzyme's catalytic activity.</p> Signup and view all the answers

    What is the primary function of the positively charged amino acids in the RNA polymerase's active site?

    <p>To interact with the negatively charged DNA phosphate backbone.</p> Signup and view all the answers

    What is the main difference between the RNA polymerase of yeast and E. coli in terms of sequence conservation?

    <p>The RNA polymerase of yeast and E. coli have a similar degree of sequence conservation.</p> Signup and view all the answers

    What is the function of the RNA polymerase's Rpb1 subunit?

    <p>To provide the main architecture of the RNA polymerase.</p> Signup and view all the answers

    What is the significance of the RNA polymerase's subdomains in terms of its structure and function?

    <p>The subdomains provide structural flexibility to the RNA polymerase during transcription.</p> Signup and view all the answers

    What is the primary function of the RNA polymerase's modules during transcription?

    <p>To provide structural flexibility to the RNA polymerase during transcription.</p> Signup and view all the answers

    What is the result of the RNA polymerase's movement along the DNA during transcription?

    <p>The RNA polymerase reads the DNA template and separates the DNA strands.</p> Signup and view all the answers

    What is the significance of the RNA polymerase's interaction with the DNA phosphate backbone?

    <p>The interaction facilitates the binding of RNA polymerase to the template strand.</p> Signup and view all the answers

    What is the primary function of the RNA polymerase's subunits during transcription?

    <p>To form a complex with other subunits to transcribe DNA.</p> Signup and view all the answers

    What is the result of the RNA polymerase's conformational changes during transcription?

    <p>The RNA polymerase can synthesize the RNA transcript more efficiently.</p> Signup and view all the answers

    What is the function of the subunit A12.2 in RNA Pol I?

    <p>To solve problems of RNA polymerase pausing</p> Signup and view all the answers

    What is the role of the TFIIS factor in RNA Pol II?

    <p>To help the RNA polymerase overcome pausing problems</p> Signup and view all the answers

    What is the characteristic of the RNA Pol I transcript?

    <p>It is a long molecule that forms a tree-like structure</p> Signup and view all the answers

    What is the function of the RNA Pol I in eukaryotes?

    <p>To transcribe the gene that codes for the ribosomal RNA</p> Signup and view all the answers

    What is the function of the nucleolus in eukaryotes?

    <p>To transcribe and process ribosomal RNA</p> Signup and view all the answers

    What is the function of the promoter region in the genome?

    <p>To initiate transcription</p> Signup and view all the answers

    What is the function of the DNA region between two transcribing regions?

    <p>To separate two genes</p> Signup and view all the answers

    What is the role of UBF in the core promoter?

    <p>To bind to another sequence upstream and induce DNA folding</p> Signup and view all the answers

    What is the composition of the SL1 complex?

    <p>TBP, TAF1A, TAF1C, and TAF1D</p> Signup and view all the answers

    What is the result of the interaction between UBF and SL1 in the core promoter?

    <p>The DNA is folded and the RNA polymerase is attracted</p> Signup and view all the answers

    What is the structure of the rRNA genes in human chromosomes?

    <p>Tandem repeats of a gene with a coding region and a spacer region</p> Signup and view all the answers

    What is the role of the topoisomerase in the transcription of rRNA genes?

    <p>To relax the DNA supercoiling during transcription</p> Signup and view all the answers

    What is the structure of the chromatin in the transcribed region of the rRNA genes?

    <p>Nucleosomes are absent in the transcribed region but present in the spacer region</p> Signup and view all the answers

    What is the result of the RNA polymerase reaching the termination zone?

    <p>The RNA polymerase is released from the DNA and the RNA</p> Signup and view all the answers

    What is the characteristic of the transcription units in the rRNA genes?

    <p>Some units are transcribed while others are not</p> Signup and view all the answers

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