transcription Flashcards

1
Q

nucleolus=

A
  • has rna
  • dense
  • site of rrna synth
  • resistant to a amanitin
  • pol a found here
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2
Q

nucleoplasm

A
  • poly b found here
  • mrna function
  • sensitive to a amanitin
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3
Q

pol c

A

found in nucleoplasm

  • sensitive to a amanitin
  • does tnra
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4
Q

a amanitin

A
  • mushroom
  • poly a is not inhibited so can make rrna
  • if low dose then poly c is also made but no b
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5
Q

rrna

A
  • most abundant form
  • prokarya has 2-10 copies
  • 100 + in eukarya
  • prokarya trim this
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6
Q

trna

A

less copies

  • once made, can be creaves with rnase, methylation or OH in prokary
  • euk: only diff is that it is processed in nucleus
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7
Q

mrna

A
  • one copy per chromosome
  • usually degraded by rnase
  • if MRNA: then poly a tail added, 5’ gtp cap
  • many proteins prevent it from degradation with “loops” of dna
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8
Q

primary transcript of ANY rna is called

A

heterogenous nucleopolasmic rna

  • found in nuc
  • hnRNA
  • can give rise to lots of rnas
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9
Q

introns

A
  • cut out loops of dna not in mrna BUT present in hnRNA

- spliceosome: cut by small nuclear rna

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10
Q

genetic code

A

1) degenerate: more than one codon for AA
2) unambiguous: AA has specific codon
3) universal

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11
Q

trna and aminoacyl

A

trna + AA –> aminoacyl + Rna

- enzyme is aminoacyl tnra synthetase, specific to each aa

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12
Q

trna structure for transcription

A
  • all end with adenine 3’

- regions with double strand and anticodon

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13
Q

amino acylation reaction

A

enzyme + AA + ATP –> complex

complex + Trna –> AA-trna + amp + enzyme

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14
Q

wobble hypothesis

A
  • trna have inosine in 5’ position
  • inosine can bond to u, a or c so it can read three codons
  • this adds to degeneracy
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15
Q

prokaryotic ribosome

A
  • 70 s
  • split to 50 + 30
    50: made of 5s + 23s + 34 proteins
    30 s; made of 16s and 21 proteins
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16
Q

eukaryotic ribosome

A

80 s
60 s: 7s rna + 28s + 50-60 proteins
40 s: 18s + 25-30 proteins

17
Q

initiation

A

n-formyl met is always starting AA
first met is added to trna using thfa
- then 30s binds, then n formly, then 50s and gtp is used up

18
Q

elongation

A
  • p side for peptide
  • a site for amino
  • then peptidyl transferase uses gtp to move the holoenzyme from a to p site and make bond
  • as protein is made, chaperone helps it fold
19
Q

end of translation

A
  • falls off at termination godon (uag stugg)

- can be translated at same time by lots of proteins called polysome

20
Q

post translational proessing

A
  • golgi
  • cleave off n formyl met
  • form disulfide bonds
  • add cofactors or prosthetic groups
  • modify any AA
  • signal sequence cut off (hydrophobic AA)
21
Q

protein degradation

A
  • ubiquitin marks it for bad protein
22
Q

lac operon

A
  • repressor region where protein is made
  • region which is promoter
  • operator region where repressor binds
  • then also lactase permease acetylase which makes mebrane permeable??!
  • on when lactose is there so repressor falls off
23
Q

cyclic amp and lac operon

A
  • when glucose and lactose, then lac operon is off

- if camp, then it binds to catabolite gene acticator (CAP) which binds to promoter and make gene

24
Q

his operon

A
  • histadine is on, then when his present, it turns off since already have his
25
Q

selective gene expression

A
  • only some genes are expressed with same dna in kid
26
Q

histones

A

made in cyto and transported to nuc

  • positive charge to bind neg dna
  • rich in lys and arg (+)
  • 5-8 types
  • no tissue spec
  • lots of mods
  • long life
27
Q

nonhistochromatin dna

A
  • both + and - proteins
  • short life
  • diverse binding to tissues
  • less post translational
  • fine tune gene expression
28
Q

liver dna + liver nhc make + THYMUS HISTONE

A

liver rna

29
Q

liver dna and thymus nhc make + liver histone

A

thymus rn

30
Q

nucleosome

A
  • beans on a string

- open dna not wrapped is transcribed

31
Q

enhancer

A
  • only in euk
  • stim trasncription
  • sites separate from promoter (up or down from gene)
32
Q

zinc finger + leucine zipper

A

histone with zinc stabilizing ions or leucine

33
Q

steroids and transcription

A
  • bidn to promote it

- go in cell, nuc then bind to dna to regulate expression