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2.5.1

  1. (key concepts) What does RNA polymerase do? (2)
    -binds to specific site in DNA with help of other proteins

    -catalyzes production of an RNA
  2. (Key concepts) What happens during RNA processing? (2)
    introns are removed

    *a cap and tail join the RNA
  3. In what direction is mRNA formed?
    It is formed in a 5' to 3' direction
  4. Image Upload 2
  5. What are the names of the 2 DNA strands?
    -non-template strand (coding)

    -template strand
  6. Which side of the DNA strand does the RNA use as a base template?
    the template strand
  7. What does the non-template strand do?
    it codes for the RNA
  8. What are promoters? (2)
    • are specific sections of DNA that are initiated during transcription
    • (bacteria only)
  9. (bacteria) What are the 2 key regions that promoters have?
    • - -10 box
    • *10 bases upstream from transcription start site

    • - -35 box
    • * 35 bases upstream from trancription start site
  10. In what direction does the RNA polymerase move during transcription?
    downstream
  11. WHat needs to happen to initiate transcription?
    Σ protein needs to bind to the -10 and -35 boxes properly to orient the RNA polymerase holoenzyme for transcription at the start site
  12. What forms the Holoenzyme? (2)
    Σ and RNA polymerase

    Image Upload 4
  13. Where do phosphodiester bonds form in RNA polymerase?
    in the active site where channels intersect
  14. (Initiation of transcription in bacteria) step 1 (4)Image Upload 6
    • -where the red thing starts after sigma, that where it starts coding
    • *then it goes downstream

    • -sigma binds to promoter regions of DNA
    • *serves as an anchor
  15. (Initiation of transcription in bacteria) step 2 (2)Image Upload 8
    -the NTPs flow inside to create the RNA strand by binding nucleotides

    -the DNA is being split
  16. Image Upload 10(Initiation complete of transcription in bacteria) step 3 (2)
    -initiation is complete

    - the sigma falls off when elongation process starts
  17. (step 3) is the upstream DNA trasncribed?
    no
  18. (step 3) what does the zipper do?
    helps unzip the DNA
  19. (step 3) what does the rudder do?
    guides the DNA along
  20. Image Upload 12 (step 4 of bacteria)(2)
    -transcription continues

    -the trancription termination signal is coming when it is fully red instead of blueish
  21. (Step 5 of bacteria) Image Upload 14
    -hairpin loop begins to happen whoch signals the end of transcription
  22. (step 6of bacteria) (2)Image Upload 16
    -mRNA is formed and detaches

    -DNA is fully read
  23. (Initiation SUmmary 5 steps of transcription in bacteria) Step 1
    - Σ opens the DNA double helix and the template strand is threaded through the RNA polymerase active site
  24. (Initiation SUmmary 5 steps of transcription in bacteria) STep 2
    • -incoming ribonucleotide triphosphate pairs with a complementary base on the DNA template strand
    • **RNA polymerazation begins
  25. (Initiation SUmmary 5 steps of transcription in bacteria) step 3
    -Σ dissociates from the core enzyme once the initiation phase of transcription is completed
  26. (elongation and termination steps summary in bacteria Transcription) step 1 (2)
    • -during elongation phase, RNA polymerase moves along the DNA template and synthesizes RNA in 5 to 3 direction
    • **it is moving downstream
  27. (elongation and termination steps summary in bacteria Transcription) step 2
    • -transcription ends with a termination phase
    • * RNA polymerase encounters a transcription termination signal in the DNA template
  28. (elongation and termination steps summary in bacteria Transcription) step 3 (3)
    • -signal codes for RNA forming a hairpin structure
    • *causing the RNA polymerase to separate from the RNA transcript
    • **ending the transcription
  29. (transcription in Eukaryotes) DO the promoters recognized by each type of RNA polymerase differ?
    yes
  30. What is a TATA box? (3)
    -a promoter that is recognized by RNA polymerase II

    -analogous functon to -10 and -35 boxes

    -thymadine and adenine
  31. What are exons? (2)
    -coding regions of eukaryotic genes that will be part of the final mRNA product

    -these are expressed in final transcript
  32. What are introns?
    intervening noncoding sequences that are not included in final mRNA
  33. Eukaryotic genes size AND Corresponding mmature mRNA
    Genes are much larger because they contained introns and exons
  34. What is the Primary RNA transcript? (2)
    -it is the transcription of eukaryotic genes by RNA polymerase

    -it contains exons and introns
  35. How are introns removed?
    they are spliced out by snRNPs
  36. What are the Small Nuclear ribonucleoproteins? (2)
    -form a complex called a spliceosome

    -this complex ^ catalyzes the splicing reaction
  37. Image Upload 18
  38. In Eukaryotes, what are mRNAs given? (2)
    a 5' cap and a Poly-A tail
  39. What happens when the mRNA is given the cap and tail? (2)
    the processing is complete

    *the prodcut is a mature mRNA
  40. What does the 5' cap do? (2)
    -provides an anchoring point when it meets up with a ribosome

    -recognition signal for the translation machinery
  41. What does the tail do? (2)
    -extends the life of an mRNA by protecting it from degradation

    -the longer the tail, the longer it stays in cell, and the more proteins it produces
Author
efrain12
ID
203947
Card Set
2.5.1
Description
transcription
Updated

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