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39 Cards in this Set
- Front
- Back
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The presence of nucleosomes can interfere with _______ and with the ___________
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the binding of TFs to enhancers
with the preinitiation complex to the promoter. |
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Simply, nucleosomes _______.
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Repress the expression of DNA
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Anitrepression or derepression
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TF binding DNA and preventing the formation of nucleosomes
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Histone classes
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H1 (H5)
H2A H2B H3 H4 |
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H4 histone has the
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most conserved amino acid sequence
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The presence of nucleosomes can interfere with _______ and with the ___________
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the binding of TFs to enhancers
with the preinitiation complex to the promoter. |
|
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Simply, nucleosomes _______.
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Repress the expression of DNA
|
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Anitrepression or derepression
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TF binding DNA and preventing the formation of nucleosomes
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Histone classes
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H1 (H5)
H2A H2B H3 H4 |
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H4 histone is the
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most conserved histone
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Stretched out DNA in a single chromosome would be _______ long?
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10 cm
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How much DNA is in a cell
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2m
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Histone 4 amino acid sequence varies by ____ amino acids between cows and peas
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2 amino acids
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At neutral pH, histones are _______ charged and migrate in the ________ direction in electrophoresis
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postively
opposite - toward the anode |
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DNA wraps around the histone _______ times
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147
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DNA binds to the histone through the ________ groove
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minor
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Scaffold associated regions allow nucleosomes to form ______.
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the solenoid
700 nm fiber |
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H1 binding stiumlates formation of
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30nm fiber
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H1 histones pull adjacent nucleosomes
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into close proximity
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Inactive oocyte genes contain _______ histones
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all 5
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Active somatic genes contain only ______ histones
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core
missing H1 |
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Removing H1 ________ oocyte genes
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turns on
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Class II mRNA encoding genes have core histones that cause
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4X repression
not affected by activators |
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Class II mRNA genes with H1 are repressed
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25 - 100 X
Activators can prevent this |
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Gal 4 interacts with histones to act as
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antirepressor and activator
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Sp1 acts as
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antirepressor and activator
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GAGA factor acts as
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antirepressor only
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De-repression or Anti-repression is the
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amount of transcription that you get when the histone is not hiding the promoter
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Bgl1 cuts SV40 minichromosome at
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one end of nucleosome free area
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BamH1 cuts SV40 minichromsome at
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opposite area of nucleosome free section
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EcoR1 cuts SV40 minichromosome at
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opposite end of nucleosome free section
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histones are acetylated at the
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NH3 group of lysine
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unacetylated histones _________ transcription
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repress
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acetylated histones __________ transcription
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activate
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HAT
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Histone acetyl transferase
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HDAC
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Histone deacetylase
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Tetrahymena has
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heavily acetylated histones
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HDAC removes
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acetyl group causing histone tail to collapse inward
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THllD is ____________ to ________.
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attracted to tails
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