Brainscape's Knowledge GenomeTM

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


See full index

MCBM Exam 5 > Transcription > Flashcards

Transcription Flashcards

1
Q

What synthesizes RNA?

A

RNA polymerases

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

What things are necessary for RNA synthesis?

A

DNA template
Ribonucleotide triphosphates
Mg2+ cofactor

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

What are the two complementary base pairs in RNA?

A

CG

AU

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

Is a primer needed to initiate RNA synthesis?

A

No

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

Why is error in RNA polymerization higher than in DNA polymerization?

A

They don’t proofread - there are a lot of mRNA copies, so the occasional error doesn’t matter

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

How many RNA polymerases doe E. coli use for transcript synthesis?

A

1

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

What does primase do in E. coli?

A

Makes short primers that never leave the template

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

How many subunits does the core of E. coli polymerase have?

A

5 - 2 alpha-subunits, 1 beta, 1 beta’ and 1 omega

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

What is the sixth subunit of E. coli that is required for efficient initiation?

A

Sigma Factor

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

What is the complete enzyme called that starts E. coli RNA polymerase?

A

RNA polymerase holoenzyme

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

What are the three stages of RNA synthesis?

A

Initiation
Elongation
Termination

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

Where is RNA synthesis initiated?

A

At promoters

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

Where is the site of transcription?

A

5’ upstream of position of translational initiation codon in the gene

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

What is the transcription start site?

A

The first base copied on the template transcribed/sense strand

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

What is the number of the transcription start site?

A

+1

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

In reference to numbering, what are the values of the upstream bases?

A

Negative (-)

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

E. coli uses variations in __ and __ sequences to creat promoters of different efficiencies.

A
  • 35

- 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the commonality of promoter sequences suggest?

A

Functional importance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where does the RNA polymerase holoenzyme first bind to the DNA in E. coli?

A

Weakly binds and slides to the -35 site; then binds tightly and forms a closed complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

After binding to the -35 site, RNA polymerase binds to the ___ site and unwinds how many base pairs?

A

-10 site

Unwinds about 17 base pairs; binds tightly to form open complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the first nucleotide brought into the active site?

A

Almost always a purine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why is a sigma subunit required?

A

To ensure specific, efficient recognition of the promoter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When is the sigma subunit lost?

A

Once several bases are incorporated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why are there different sigma subunits?

A

To allow different promoters to be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What facilitates the unwinding of DNA?

A

-ve supercoiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

At termination, why does RNA polymerase dissociate from the template?

A

It lacks a sigma subunit, not promoter and is not elongating a chain; it can’t bind to DNA without those things

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the 2 mechanisms for transcriptional termination in prokaryotes?

A

Rho dependent

Rho independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How does Rho dependent termination work?

A

Rho protein binds to poorly characterized sequences in the 3’ region of the transcript; uses ATP to break H bonds holding transcript to template

29
Q

What drives Rho independent termination?

A

Secondary structure formation of RNA transcript and thermodynamics

30
Q

In Rho independent termination, what reduces the base pairing template?

A

The region of transcript folds into a hairpin loop

31
Q

After RNA forms a hairpin loop, what causes the DNA to rewind?

A

A U-rich environment that causes poor hydrogen bonding to template

32
Q

In eukaryotes, typical mRNA promoter has what?

A

TATA box about 25 bases upstream of the +1 transcription start site

33
Q

In eukaryotes, what does Pol II do?

A

Catalyzes RNA synthesis

34
Q

In eukaryotes, what does TBP do?

A

Recognizes the TATA box

35
Q

In eukaryotes, what does TFIIA do?

A

Stabilizes TFIIB and TBP binding to promoter

36
Q

In eukaryotes, what does TFIIB do?

A

Binds TBP

Recruits Pol II-TFIIF complex

37
Q

In eukaryotes, what does TFIIE do?

A

Recruits TFIIH

Has ATPase and helicase activities

38
Q

In eukaryotes, what does TFIIF do?

A

Binds Pol II

Binds TFIIB and prevents nonspecific binding of Pol II

39
Q

In eukaryotes, what does TFIIH do?

A

Unwinds DNA at promoter

Phosphorylates Pol II within CTD

40
Q

What is a newly synthesized RNA molecule called?

A

Primary transcript

41
Q

What are constitutive genes?

A

Genes that are involved in making things that we need all the time, like the enzymes of glycolysis and the TCA cycle

42
Q

What are the core promotor proteins?

A

Pol II, TBP, TFIIA, TIFFB, TFIIE, TFIIF, TFIIH

43
Q

What does TBP stand for?

A

TATA binding protein

44
Q

What shape is tRNA usually in?

A

Cloverleaf

45
Q

Where is the anticodon region of tRNA usually found?

A

Across from the “open”end

46
Q

What is always found at the 3’ end of every tRNA?

A

A CCA

47
Q

Why is it important to have a CCA on the 3’ end of tRNA?

A

That is where the amino acids bind

48
Q

What does the tRNA anticodon base pair with?

A

The RNA template

49
Q

RNA is transcribed as one big precursor. What happens to get all the forms of RNA?

A

Primary transcripts must be cleaved into functional fragments

50
Q

Where are tandem arrays of rRNA found?

A

Nucleolar regions

51
Q

When are tandem arrays of rRNA processed?

A

Post-transcriptionally

52
Q

What chromosomes make up the nucleolar regions?

A

13-15, 21, 22

53
Q

What is the “ribosomal factory”?

A

Nucleoli

54
Q

After being arranged into subunits, where are rRNA and ribosomal proteins shipped?

A

To the cytoplasm

55
Q

What 3 thing are required to make a mature mRNA?

A

5’ cap
3’ polyA tail
Introns spliced out

56
Q

What is the poly A addition signal?

A

AAUAAA

57
Q

When the PolyA addition signals is recognized by the enzyme complex, what happens?

A

The enzyme complex cleaves the transcript 10-30 nucleotides 3’ to signal

58
Q

What tethers mRNA to CTD of Pol II?

A

Cap binding complex

59
Q

In mRNA splicing, what is the cap tethered to?

A

RNA polymerase

60
Q

What mediates mRNA splicing?

A

snRNA (called U1-U6)

61
Q

snRNA’s come together to form what?

A

Spliceosome complex

62
Q

How do mRNAs get spliced?

A

snRNAs build spliceosome, then bring in 5’ splice junction next to the branch point adenosine, form a loop, cut off both sides and allow them to ligate (I think)

63
Q

What is usually larger, introns or exons?

A

Introns

64
Q

Often, the introns spliced out are not junk. What are they/why are they spliced out?

A

Tissues can decide what do splice; usually introns that are spiced out are for use in different tissues

65
Q

What type of RNA is most commonly edited?

A

In mitochondrial transcripts

66
Q

What is rifamycin (rifampicin)?

A

Antibiotic that inhibits prokaryote RNA polymerase

67
Q

How does rifamycin work?

A

Blocks the initiation of transcription

68
Q

What does rifamycin treat?

A

TB

69
Q

What does alpha-amanitin affect?

A

RNA Pol II

Blocks mRNA synthesis

MCBM Exam 5 (11 decks)

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