LACOFINAL

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cooxcooxbananas
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179502
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LACOFINAL
Updated:
2012-10-23 22:39:03
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LACO
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LACO
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  1. Early genes in the SPO I Infection of Bacillus subtilis are expressed within what time range?
    0-5 minutes
  2. Middle genes in the SPO I Infection of Bacillus subtilis are expressed within what time range?
    5-10 minutes
  3. Late genes in the SPO I Infection of Bacillus subtilis are expressed within what time range?
    10 mins until lysis
  4. Transcription of a gene can be ______ or _______.
    increased or decreased
  5. Transcriptional regulation involves the actions of two main types of ____________ that bind DNA.
    regulatory proteins
  6. ___________ involves the actions of two main types of regulatory proteins that bind BNA
    Transcriptional
  7. What binds to DNA and inhibits transcription
    Repressors
  8. What binds to DNA and increases transcription?
    Activators
  9. What can cause the activator and repressor proteins to either bind or dissociate from DNA?
    small molecule effectors
  10. Small effector molecules affect...
    transcription regulation
  11. how does small effector molecules affect transcritpion regulation?
    binding to regulatory proteins
  12. The effectors that may increase transcription are called...
    inducers
  13. What are the two ways that inducers function?
    • 1) Bind activator proteins and cause them to bind to DNA
    • 2) Bind repressor proteins and prevent them from binding to DNA
  14. Genes that are regulated by inducers are said to be...
    inducible
  15. Two way that inhibitors function to inhibit transcription are...
    • 1) Corepressors bind to repressors and cause them to bind to DNA
    • 2) Inhibitors bind to activators and prevent them from binding to DNA
  16. Genes that are regulated by inhibitors are termed...
    repressible
  17. Inducers ________ binding of a repressor.
    inhibit
  18. Inducer ______ binding of an activator
    enhances
  19. Inhibitors _________ binding of an activator
    prevents
  20. Corepressor ________ binding of a repressor
    enhances
  21. What is an operon?
    a regulatory unit consisting of three structural genes under the control of one promoter
  22. An operon encodes...
    a polycistronic mRNA
  23. The polycistronic mRNA contains...
    the coding sequence for the three structural genes
  24. the operon encoding for the polycistronic mRNA allows for what?
    coordinate regulation of a group of genes that usually encode proteins with a common function
  25. What is the structure of the lac operon left to right?
    • lac promoter
    • operator
    • lacZ
    • lacY
    • lacA
    • lac terminator
  26. lacZ encodes for...
    Beta-galactosidase
  27. what is lacz two functions?
    • enzymatically cleaves lactose
    • converts lactose into allolactose (an iosmer)
  28. allolactose is an...
    isomer
  29. what is the functional importance of lacY
    transports lactose. (membrane protein required for transport of lactose)
  30. What is the function of lacA?
    covalently modifies lactose
  31. If no lactose is present, the lac repressor binds to the operator and it will...
    inhibit transcription
  32. if lactose is present, the allolactose (inducer) will...
    bind to prevent the lac repressor from binding to the operator site to allow initiation of transcription
  33. where are the location of the three operators in the lac operon? (O1, O2, O3)
    • O1= between the promotoer and lacZ
    • O2= Right after the lacZ
    • O3= Right before the promoter
  34. What happens when the inducer binds to the lac repressor?
    decreases the lac repressor's affinity for the operator site
  35. The complete structure of the promotoer-operator region of the lac operon (left to right)
    • I gene
    • CAP/cAMP binding (P)
    • RNA polymerase binding site (P)
    • Operator
    • Z gene
  36. What two section make up the promoter in the lac operon? (left to right)
    • CAP/cAMP binding site
    • RNA Polymerase binding site
  37. High Glucose -> ______ cAMP
    low
  38. Low Glucose ---> ____ cAMP
    High
  39. There is an inducible syntheis of the lac operon gene products in the E.Coli partial diploid because...
    the wild-type (lacl+) repressor binds to the lac operators on both chromosomes
  40. Lac Operator (lacO) functions only in...
    cis
  41. In the e.coli partial diploid if the inducer is absent, what happens?
    the functional lac operon gene products are snythesized
  42. Lactose, no glucose ______cAMP
    high
  43. No lactose or glucose ____cAMP
    high
  44. Lactose and glucose, ______ cAMP
    low
  45. Glucose, no lactose _______ cAMP
    low
  46. When CAP binds in inhibits...
    glucose
  47. What is the gene regulation expression that occurs in genes during transcription?
    • 1) Genetic regulatory proteins bind tothe DNA and control the rate of transcription.
    • 2) In attenuation, transcription terminates soon after it has begun due to the formation of a transcriptional terminator.
  48. What is the gene regulation expression that occurs in mRNA during translation?
    • 1) Translational repressor proteins can bind to the mRNA and preventtranslation from starting.
    • 2) Riboswitches can produce an RNA conformation that prevents translationfrom starting.
    • 3) Antisense RNA can bind to the mRNA and prevent translation from starting.
  49. What is the gene regulation expression that occurs in proteins during posttranslation?
    • 1) In feedback inhibition, the product of a metabolic pathway inhibits the first enzyme in the pathway.
    • 2) Covalent modifications to the structure of a protein can alter its function.
  50. A repressor is a...
    regulatory protein
  51. An inducer is a
    effector molecule
  52. An operator site is a
    DNA segment
  53. A corepressor is a...
    effector molecule
  54. an activator is a...
    regulatory protein
  55. an attenuator is a...
    DNA segment
  56. An inhibitor is a
    effector molecule
  57. an attenuator is a DNA segment that causes..
    premature termination in transcription
  58. A mutation that has a cis-effect is within a.......
    genetic regulatory sequence
  59. An example of a genetic regulatory sequence is ...
    an operator site, that affects the binding of a genetic regulatory protein.
  60. A cis-effect mutation affects...
    only the adjacent genes that the genetic regulatory sequence controls.
  61. A mutation having a trans-effect is usually in....
    a gene that encodes a genetic regulatory protein.
  62. A transeffect mutation can be complemented in a merozygote experiment by the introduction of...
    a normal gene that encodes the regulatory protein.
  63. In the lac operon, how would gene expression be affected if the lac operon promoter was missing? Why?
    • No transcription would take place.
    • The lac operon could not be expressed.
  64. In the lac operon, how would gene expression be affected if the operator site was missing? why?
    • No regulation would take place.
    • The operon would be continuously turned on.
  65. In the lac operon, how would gene expression be affected if the lacA gene was missing?
    The rest of the operon would function normally, but none of the transacetylase would be made.
  66. Would a mutation that inactivated the lac repressor and prevented it from binding to the lac operator site result in the constitutive expression of the lac operon under all conditions?
    A mutation that prevented the lac repressor from binding to the operator would make the lac operon constitutive only in the absence of glucose. (However, this mutation would not be entirely constitutivebecause transcription would be inhibited in the presence of glucose)
  67. Whatis the disadvantage to the bacterium of having a constitutive lac operon?
    the bacterial cell would waste a lot of energy transcribing the genes and translating the mRNA when lactose was not present.

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