Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecular Processes (2038A) > Transcription > Flashcards

Transcription Flashcards

1
Q

RNAs transcribed in both prokaryotes and eukaryotes

A
  • mRNA (messenger)
  • rRNA (ribosomal)
  • tRNA (transfer)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

RNA produced only in eukaryotes

A
  • pre-mRNA (pre-messenger)
  • snRNA (small nuclear)
  • snoRNA (small nucleolar)
  • miRNA (micro)
  • siRNA (small interfering)
  • piRNA (piwi-interacting)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

RNA produced only in prokaryotes

A

CRISPR RNA (crRNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Function of rRNA

A

Ribosomal rna : structural and functional components of ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Function of mRNA

A

Messenger RNA: Carrie’s genetic code for proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Function of tRNA

A

Transfer RNA: helps incorporate amino acids into polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Function of snRNA

A

Small nuclear RNA: processing of pre-mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Function of snoRNA

A

Small nucleolar RNA : processing and assembly of tRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Function of miRNA

A

MicroRNA: inhibits translation of mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Function of siRNA

A

Small interfering RNA: triggers degradation of other RNA molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Function of piRNA

A

Piwi-interacting RNA : suppresses the transcription of transposable elements in reproductive cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

function of crRNA

A

CRISPR RNA: assists destruction of foreign DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What direction does transcription proceed

A

5’ —> 3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Components of bacterial RNA polymerase

A
  • 2x α subunits, β, β’,ω & σ

Core enzymes (without σ) is catalytically active, but binds non-specifically

σ directs RNA polymerase to the promoter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 3 stages of bacterial transcription

A

Initiation
Chain elongation
Termination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens in initiation of bacterial transcription

A
  • promoter recognition
  • formation of transcription bubble
  • creation of first bonds between rNTPs
  • escape of transcription apparatus from promoter
17
Q

What happens during chain elongation of bacterial transcription

A

RNA polymerization reaction

18
Q

What happens during termination of bacterial transcription

A
  • ρ dependent termination

- ρ independent termination

19
Q

What is TTGACA

A

Consensus sequence on bacterial promoter with charge -35

20
Q

What is TATAAT

A

The pribnow box consensus sequence on bacterial promoter with charge -10

21
Q

What charge does the transcription start site on bacteria have

A

+1

22
Q

6 steps of initiation of transcription in bacteria

A
  1. Sigma factor associates with core enzyme to form Holoenzyme
  2. Bind to -35 and -10 consensus sequences in promoter
  3. Holoenzyme bind the promoter tightly and unwinds the double stranded DNA
  4. RNTP complementary to base at start site serves as first nucleotide in RNA molecule
  5. Two phosphate groups are cleaved from subsequent nRTP, creating rna nucleotide that is added to 3’ ends of growing mRNA
  6. Sigma factor released as the RNA polymerase moves beyond promoter
23
Q

Discuss DNA bending in the operon- promoter complex

A
  • rna polymerase forms a closed complex in which dna is not unwound
  • stable open complex forms where the -10 region is unwound
  • an mg2+ dependent isomerization further unwinds the DNA from -12 to +2
24
Q

How does transcription bubble occur

A

Nucleophilic attack by the 3’-OH of the first nucleotide on the α-phosphate of the seconds nucleotide forms a phosphodiester bind in a manner analogous to dna replication (5’ to 3’)

As process continues, the dna is continuously unwound in a transcription bubble

25
Q

What does topoisomerase do during elongation

A

Remove negative supercoils

26
Q

What does gyrase do during elongation

A

Introduce negative supercoils

27
Q

Is rna polymerase activity continuous or discontinuous ?

Explain

A

Discontinuous

When the RNA polymerase reaches a site difficult to transcribe it may pause or shift backwards

Transcription can then resume either by the polymerase sliding forward or by cleavage of the non-base-paired part of the transcript

28
Q

6 steps of rho -independent transcription termination in bacteria

A
  1. Rho-independent terminator contains an inverted repeat followed by a string of approximately 6 adenine nucleotides
  2. The inverted repeated are transcribed into rna
  3. String of Us cause the rna polymerase to pause
  4. The inverted repeats fold into a hairpin
  5. Destabilize DNA-RNA pairing
  6. Rna transcript separates from the template, terminating transcription
29
Q

3 steps of Rho-dependent termination in bacteria

A
  1. Rho binds to rut site and moves toward the 3’ end
  2. When rna polymerase encounters a terminator sequence it pauses and rho catches up
  3. Using helicase activity, rho unwinds the dna-rna hybrid and brings an ends to transcription
30
Q

3 steps of factor-dependent termination

A
  1. Binding of ρ to dna-rna-polymerase complex
  2. ρ moves toward 3’ end, displacing dna template strand
  3. Weakens interaction between template and transcript, causing them the dissociate
31
Q

What happens during the initiation of eukaryotic mRNA transcription

A
  • assembly of basal transcriptional apparatus on core promoter
  • binding of TFs to enhancers
  • formation of transcription bubble
  • first binds between rNTPs
  • escape of rna polymerase II from promoter
32
Q

What are the 4 regions on the eukaryotic core promoter

A
  1. TFIIB recognition element (-35)
  2. TATA box (-25)
  3. Initiator element (+1)
  4. Downstream core-promoter element (+30)
33
Q

5 steps of eukaryotic transcription initiation

A
  1. TFIID binds to TATA box in core promoter
  2. Transcription factors and RNA polymerase II bind to core promoter
  3. Transcriptional activator proteins bind to sequences in enhancers
  4. Dna loops out, allowing the proteins bound to the enhancer to interact with the basal transcription apparatus
  5. Transcriptional activator proteins bind to sequences in the regulatory promoter and interact with the basal transcription apparatus through the mediator
34
Q
  1. Steps of eukaryotic transcription termination
A
  1. Rna polymerase II transcribed well past coding sequence
  2. Cleavage near 3’ end of rna
  3. Rna polymerase continues to transcribe
  4. Rat1 endonuclease attached to 5’ ends of trailing rna
  5. Moves toward rna polymerase degrading the rna as it goes
  6. When rat1 reaches the polymerase, transcription is terminated
35
Q

What does mRNA processing involve

A
  • capping
  • cleavage of transcript
  • polyadenylation
  • splicing
  • rna export from nucleus
36
Q

What function does the addition of 5’ cap have

A

Facilitates binding of ribosome to 5’ end of mRNA, increases rna stability and enhances RNA splicing

37
Q

What functions do 3’ cleavage and addition of polyAtail have

A

Increases stability of mRNA, facilitates binding of ribosome to mRNA

38
Q

What function does RNA splicing have

A

Removes non coding introns from pre-mRNA, facilitates export of mRNA to cytoplasm, allows for multiple proteins to be produced through alternative splicing

39
Q

What is alternative splicing

A

Producing different mRNAs from the same nRNA by linking together different combinations of potential exons

Molecular Processes (2038A) (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions