RR2 Flashcards

1
Q

what is major regulator of gene expression

A

transcriptional control

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2
Q

describe percentages of gene expression

A

most outcomes of gene expression are dictated by Rates of transcription (73%)
MRNA translation (8%)
protein degradation (8%)
Mrna degradation (11%)

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3
Q

describe overview of transcription - why is polymerization energetically favoured by

A

high energy bond between alpha and beta phosphate is replaced

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4
Q

describe conventions for transcription rna transcript

A

dna pol read 3’ –> 5’
usptream = negative
transcription start site = +1
downstream = positive
utr = untranslated regions

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5
Q

what is premrna

A

not been processed yet

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6
Q

how fast does rna pol 2 advance

A

rate of 1000-3000 nt/min
not super fast but still fast

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7
Q

describe longest human gene

A

dmd = dystrophin
takes a day to transcribe once
for the rna pol to transcribe through it
must be very faithful = not make mistakes - cannot just fall off

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8
Q

name 3 stages of transcription

A

initiation
elongation
termination

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9
Q

describe initiation -3 stages of transcription

A

polymerase binds to the promoter sequence, locally denatures DNA & Catalyzes
the First phosphodiester linkage
promoter elements Recruit RNA pol, Catalyzes Reaction
+1 Site

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10
Q

describe elongation -3 stages of transcription

A

polymerase advances 3’–>5’ down template strand
denatures dna and polymerizes rna
generates molecules 5’ –> 3’

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11
Q

describe termination -3 stages of transcription

A

polymerase recognizes a stop site
releases completed rna
dissociates from dna
sequence gives signal to rna or dna pol to let go and fall of

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12
Q

are prokaryotic and eukaryotic transcription similar

A

yes but also distinct

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13
Q

Describe sigma factors

A

confer specificity to rna pol so correct gene transcribed

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14
Q

describe dna binding proteins

A

regulate rate of rna synthesis by enhancing or impeding rna pol binding to promoter regions

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15
Q

describe sequences in dna proximal to transcribed gene

A

Critical for efficient transcription

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16
Q

describe transcription for prokaryotes

A

Transcription is means of adapting - lots of allosteric effects

17
Q

describe transcription for eukaryotes

A

essential during embryogenesis - distinguish all cell types - make complex organisms
30 trillion cells and 200 diff cell types

18
Q

what does polycistronic mean

A

Prokaryotes
several products from one rna

19
Q

what does monocistronic mean

A

eukaryotes
one rna –> one gene product

20
Q

describe toxin alpha amanitin

A

mushroom toxin
use ion exchange chromatography
assay each fraction for ability to make rna

21
Q

describe what toxin alpha amanitin will do to body

A

drug blocks some rna pols and destroys liver and blocks some rna polymerase

22
Q

describe sensitivities of dna polymerases to toxin alpha amanitin

A

rna pol 1 = insensitive
rna pol 2 = very sensitive
rna pol 3 = intermediate sensitivity

23
Q

describe rna pol 1

A

pre rrna (28s,18s, 5.5s)
involves in ribosome - components, synthesis

24
Q

describe rna pol 2

A

mrna
snrna (small nuclear, produced in splicing)
sirna (small interfering)
mirnas (micro)
involved in encodes protein, rna splicing, chromatin mediated repression, transcriptional control

25
describe rna pol 3
trna 5s rna snrna u6 7s rna other small stable rnas involved in protein synthesis, ribosome component, rna splicing, signal recognition, various functions, unknown for many
26
describe similarities between rna pols
They all exist in multimeric complexes some show significant similarity to bacterial subunits .most are essential
27
what is ctd
carboxyterminal domain on rna pol 2 series of repeats - needed to live if get ride = compromise viability
28
describe ctd
close to where rna exits Intrinsically disordered domains
29
describe clamp domain
when have few nts of rna made = clamp domain will close up tight around dna = initiated elongation want to be as possessive as possible
30
describe phopshorylation of ctd
during transcription, at or after transcription initiation
31
what colours correspond to actively transcribing and not transcribing genes and why
red = phosphorylated ctd = puffs where being transcribed green = unphosphorylated ctd
32
what is phosphorylation of ctd of large subunit associated with
active transcription morphologically distinct puffs
33
when does clamp domain enhance possessiveness of rna pol 2
enhances posessivity during elongation