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Flashcards in Transcription Deck (53)
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1
Q

DNA–>mRNA–>Polypeptide

(transcribed) (translated)

A

Central Dogma of Molecular Biology

2
Q

Label nucleotides with (-) numbers

A

Upstream of the +1 site

3
Q

Label nucleotides with (+) numbers

A

Downstream of the +1 site

4
Q

Place where transcription starts

-NOT the start codon

A

+1 site

5
Q

Where transcription stops

-NOT stop codon

A

Stop

6
Q

Molecules involved in transcription

A
mRNA
DNA
transcription factors
RNA polymerase
nTPs (ATP, CTP, GTP, UTP)
7
Q

Strand involved with transcription

A

DNA template strand

8
Q

Strand not involved with transcription

A

DNA coding strand

9
Q
  1. DNA is locally ______.
A

denatured

10
Q
  1. ______assembles NTPs completemtary to the template strand
A

RNA polymerase

11
Q
  • Reads the template 3’ to 5’
  • no primer needed
  • synthesizes 5’ to 3’
A

RNA polymerase

12
Q
  1. RNA/DNA duplex ________ when bigger than ______ base pairs.
A

dissociates; 20.

13
Q
  1. ____________ template reannealed behind bubble.
A

Coding

14
Q

RNA transcript is the same as _______ strand except it has uracil instead of thymine

A

coding

15
Q

Major steps in transcription

A
  1. Initiation
  2. Elongation
  3. Termination
16
Q

Sequence with a specific function

A

consensus sequence

17
Q
  • It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase to gene promoters.
  • Positions polymerase in the correct location
A

sigma subunit of bacterial RNA polymerase

18
Q

Step 1: Initiation in E. coli

A
  1. Sigma binds to 2 consensus sequences -10 box and -35 box.
    - this orients polymerase at the +1 site.
  2. RNA polymerase synthesizes RNA
    - no primer is needed
19
Q

The sigma subunit of bacterial RNA pol. ______.

a. binds to a bacterial gene’s promoter
b. is composed of both polypeptide and RNA molecules
c. is required for RNA polymerization
d. is required for termination of transcription
e. is required for ribosomal binding

A

a. binds to a bacterial gene’s promoter

20
Q

“new strand”

A

nascent strand

21
Q

______ in mRNA causes RNA to stop transcribing.

A

Hairpin

22
Q

Step that occurs when RNA/DNA duplex is dissociated by a helicase called Rho

A

termination

23
Q

Differences between prokarytoic and eukaryotic transcription

A

prokaryotes:

  • 1 RNA pol.
  • no RNA processing
  • Coupled transcription and translation
  • polycistronic RNA

Eukaryotes:

  • 3 RNA
  • Introns removed
  • Transcription and translation not coupled
  • Nuclear export (due to nuclear envelope & membrane)
  • Capping
  • Polyadenlation
  • monocistronic RNA
24
Q

Many genes encoded in same RNA molecule.

prokaryotes

A

Polycistronic

25
Q

One gene encoded in same RNA molecule.

eukaryotes

A

Monocistronic

26
Q

RNA pol I in Eukaryotes

A

RNA in nucleolus

27
Q

RNA pol II in Eukaryotes

A

mRNA + snRNA

-found in nucleoplasm

28
Q

small nuclear RNA

  • their primary function is in the processing of pre-mRNA in the nucleus.
  • They have been shown to aid in the regulation of transcription factors, and maintaining the telomeres.
A

snRNA

29
Q

RNA pol III in Eukaryotes

A

tRNA + one kind of rRNA

found in nucleoplasm

30
Q

Polymerases in Eukaryotes

A
  1. RNA pol I
  2. RNA pol II
  3. RNA pol III
    - none can bind directly to DNA, need txn factors
31
Q

Major steps in transcription

A
  1. Initiation
  2. Elongation
  3. Termination
32
Q

Step 1: Initiation in Eukaryotes

A
  • general transcription factors bind to the core promoter

- GTFs recruit polymerase to form the preinitiation complex (PIC)

33
Q

Are name according to the polymerase the recruit.

ex TF II A where II= RNA pol II interacion and A=1st to be discovered

A

General Transcription Factors

34
Q

Recruitment of polymerase by GTFs is __________.

A

increased by activators bound to enhancer sequences.

35
Q

A region of DNA that recognizes the transcription machinery and binds one or more proteins that regulate transcription initiation.

  • are necessary for transcription to be initiated accurately and at a basal level.
  • located immediately adjacent to the genes they regulate.
A

Promoter

36
Q

Subcategories within Eukaryotic promoter

A
  1. Core Promoter

2. Proximal Promoter Elements

37
Q

Determines the accurate initiation of transcription by RNA pol. II

A

Core promoter

38
Q

Modulate the efficinecy of basal levels of transcription.

A

Proximal promoter elements

39
Q

These proteins bind to genes at sites known as enhancers and speed the rate of transcription

A

Activators

40
Q

These proteins bind to selected sets of genes at all sites known as silencers and thus slow transcription

A

Repressors

41
Q

These “adapter” molecules integrate signals from activators and perhaps repressors

A

Coactivators

42
Q

In response to injunctions from activators, these factors position RNA pol. at the start of transcription and initiate the transcription process.

A

Basal transcription factors

43
Q

Step 2: Elongation in Eukaryotes

A
  • RNA pol. II can denature DNA to form a transcription bubble
  • catalyzes NTP addition to 3’ end of RNA
  • during transcription (cotranscriptionally):
    1. 5’ methyl G cap added to RNA
    2. Splicing of introns
44
Q

Short nucleotide sequences that bind specific regulatory factors

A

Promoter Elements

45
Q

Sequence that is located on the same chromosome as the gene that it regulates

A

Cis-acting sequence

46
Q

Can regulate a gene on any chromosome

-ex. DNA-binding protein

A

Trans-acting factors

47
Q
  • Protect RNA from exonucleases
  • Correct position of ribosome during translation
  • Exonucleases cannot work with this 5’ to 5’ linkage
A

5’ methyl G capping

48
Q

Many eukaryotic genes contain long insertions of non-coding sequences called ________.

  • intervening
  • transcribed but not translated
A

Introns

49
Q

Expressed sequence

-transcribed and often times translated

A

Exons

50
Q

Complex of proteins and RNA that performs the removal of introns

A

Spliceosome

51
Q

Step 3: Termination in Eukaryotes through polyadenylation

A
  • mRNA is cleaved at a polyA site
  • mRNA released
  • 50 to 250 adenine nucleotides added to the 3’ end by polyA polymerase
    • protection from 3’ to 5’ exonucleases
    • aids in translation
52
Q

Structure of a mature eukaryotic mRNA

A

5’ cap——-5’ UTR——-protein coding region——–3’ UTR——-3’ polyA tail

  • UTR= untranslated region
  • translational start site btwn 5’ UTR and protein coding region
  • translational stop site btwn 3’ UTR and protein coding region
53
Q

The polyA tail of mRNAs __________.

a. is added to the 3’ end of mRNAs
b. is found on mature eukaryotic mRNAs
c. is added at the end of transcription
d. helps prevent degradation of eukaryotic mRNAs
e. all of the above are correct

A

e. all of the above are correct