Brainscape's Knowledge GenomeTM

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


See full index

Cellular Composition > Regulation of Gene Expression in Eukaryotes > Flashcards

Regulation of Gene Expression in Eukaryotes Flashcards

1
Q

How many RNA polymerases do eukaryotes have?

A

3

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

What is the function of RNA polymerase II?

A

Transcribes DNA to pre-mRNA

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

Does transcription need a primer to be initiated?

A

No

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

What is the function of a promoter in eukaryotes?

A

Determines the site of transciption initiation and directs binding of RNA polymerase II

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

What are untranslated regions (UTRs)?

A

Transcribed non-protein coding sequences at mRNA 5’ and 3’ ends

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

Where do activators bind?

A

To distal control elements

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

What is TBP and what is its purpose?

A

TATA binding protein, it recruits basal transcription factors which in turn recruit RNA polymerase II

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

When does a transcription bubble form?

A

After recruitment of helicase

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

What is required for RNA polymerase II to recognise and bind to promoters?

A

Basal trancription factors

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

What is pre-mRNA made up of?

A

Introns, exons, and untranslated regions

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

How many maturation processes does pre-mRNA undergo?

A

3

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

What does a splicesome recognise?

A

gu…ag sequence within pre-mRNA introns

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

Outline the maturation processes of pre-mRNA

A
  • 5’ met-7G CAP addition
  • Pre-mRNA splicing
  • 3’ cleavage and polyadenylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the advantage of 5’ to 3’ processing?

A

Promotes mRNA stability and translational efficiency

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

What is alternative splicing?

A

Mutiple mRNAs can be produced from a single gene resulting in multiple protein isoforms and mutiple interactions

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

How does alternative splicing work?

A

Joining of different exon combinations (the exons must be sequential)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where are mature mRNA molecules exported from and to?

A

From the nucleus, to the cytoplasm

18
Q

Are transcription and translation linked in eukaryotes?

A

No

19
Q

What features of translation are conserved between prokaryotes and eukaryotes?

A

Codon degeneracy and tRNA charging

20
Q

What does eIF stand for?

A

Eukaryotic initiation factor

21
Q

What does a eukaryotic ribosome dissociate into?

A

40s and 60s subunits

22
Q

Do eukaryotes have shine dalgarno sequences?

A

No

23
Q

How are the 40s and 60s ribosomal subunits kept separate?

A

eIF3 and eIF6

24
Q

Describe the steps involved in the assembly of the pre-initiation complex at the TATA box

A
  • TATA binding protein is recruited and binds to the core promoter
  • TBP recruits basal transcription factors
  • These in turn recruit RNA polymerase II
  • DNA helicase is then recruited and a transcription bubble is formed
25
Q

Which eIFs are involved in the separation of ribosomal subunits?

A

eIF3 (binds to 40s subunit) and eIF6 (binds to 60s subunit)

26
Q

Which subunit is involved in the formation of the pre-initiation complex?

A

40s subunit

27
Q

What eIF is met-tRNAi associated with?

A

eIF2

28
Q

What form is the met-tRNAi in the pre-initation complex?

A

GTP form

29
Q

What eIFs are used to help recruit rRNA to the correct position on 40s ribsomal subunit?

A

eIF1, eIF1A, and eIF5

30
Q

In the initial step of initiation; what happens?

A

The pre-initiation complex binds to methyl CAP-binding complex

31
Q

What is scanning in the context of initation?

A

The process by which the pre-initation complex moves along mRNA looking for a start codon

32
Q

What is a Kozak sequence?

A
  • The sequence which must surround the start codon for a pre-initation complex to recognise the AUG
  • AUG must have a purine at a -3 position
  • AUG must have a G at a +4 position
33
Q

What occurs when the pre-initation complex finds an AUG in a Kozak sequence?

A
  • It pauses
  • Hydrolyses GTP and GDP to lock it in place
  • Allows initation factors around the complex to be released
  • This allows the 60s subunit to rejoin the complex
34
Q

How is the 60s subunit attached to the 40s subunit?

A

Brought in by eIF-5B•GTP which is hydrolysed when the subunit binds

35
Q

Which site is the first tRNA put in?

A

P site

36
Q

Which eEF is responsible for releasing and recycling eEF-1α•GDP?

A

eEF-1βγ

37
Q

What is the first step in translation elongation in eukaryotes?

A

eEF-1α•GTP brings a charged aa-tRNA to the A site, the eEF is then hydrolysed

38
Q

What mediates the formation of a peptide bond between the C-terminus of aa in the P site and the N terminus of the aa in the A site?

A

28s rRNA of the 60s subunit

39
Q

Which eEF is involved in the repositioning of the tRNAs?

A

eEF2•GTP

40
Q

Outline how translational termination in eukaryotes occurs

A
  • Stop codons recruit eRF1 which binds to the A site and is joined by eRF3•GTP
  • Hydrolysis occurs to produce eRF3•GDP which causes the peptide chain to be released and the ribosome to dissociate

Cellular Composition (15 decks)

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