Chapter 36 - Transcription

Question 0

What does the promoter do?

Answer 0

It is where the RNA polymerase binds to to ensure the right start site
binds 30 nucleotides upstream of the start site

Question 1

Differentiate cis-acting factor from trans-acting factor

Answer 1

Cis-acting = regulates nearby gene expression

Trans- acting = proteins that bind to cis factors and regulate that gene mismo

Question 2

Promoter for prokaryotes?

Answer 2

TATAAT box or Pribnow box

Question 3

Promoter for eukaryotic DNA

Answer 3

TATA box or Higness box

Question 4

DNA sequences that accelerates trasncription

Answer 4

Enhancers

Question 5

DNA sequences that inhibit transcription

Answer 5

Silencers

Question 6

Where is the mRNA found? What is its function?

Answer 6

primarily in the nucleus then goes out to cytoplasm

copies the information from the DNA template strand

Question 7

What does the sigma factor do?

Answer 7

The sigma factor finds the promoter via high affinity base pair
Only found in prokaryotes

Question 8

What is the function of 7-methylguanosine triphosphate caps?

Answer 8

They are needed for the processing of mature mRNA and to prevent exonucleolytic attack

Question 9

RNA Polymerase that synthesizes rRNA

Answer 9

RNAP I

Question 10

RNA Polymerase that synthesizes mRNA, miRNA, SnRNA?

Answer 10

RNAP II

Question 11

What toxin is RNAP II sensitive to?

Answer 11

alpha-amanitin toxin

Question 12

RNA Polymerase that synthesizes tRNA and microRNA?

Answer 12

RNAP III

Question 13

What does (+1) mean?

Answer 13

start of transcription site
5’ terminal of mRNA
beyond is downstream

Question 14

What does (-1) mean?

Answer 14

It marks the promoter region

proceeds away from the initiation site (upstream)

Question 15

termination protein for prokaryotes? Describe it?

Answer 15

Rho factor - ATP-dependent RNA stimulated helicase that disrupts RNA-DNA complex

Question 16

if a gene does not have a TATA box then how is the promoter region known?

Answer 16

By the frequency of GC/CAAT boxes

Question 17

If the eukaryotes do not have sigma factor then how is the RNAP guided to promoter region?

Answer 17

Via trans-acting element: General Transcription Factors (GTFs)

Question 18

component of TFIID?

Answer 18

TATA binding proteins + 14 TAFs

Question 19

What is the function of TFIIF?

Answer 19

equivalent od bacterial sigma factor

tethers RNAP to correct start site

Question 20

What is the function of TFIIH?

Answer 20

It has a:
Helicase - causes local unwinding
Kinase - phosphorylases RNAP, allowing clreaing of promoter

Question 21

What is the function of TFIID?

Answer 21

Binds to the TATA box promoter element

Question 22

When is RNA Polymerase II activated?

Answer 22

When Ser and Thr of Carboxyl Terminal Repeat Domain (CTD) are phosphorylated

Question 23

How to access promoter sequence wrapped in nucleosomes?

Answer 23

transcription factors bind to DNA then recruits chromatin remodelling and modefying coregulatory factors

Question 24

Differentiate Stepwise Assembly from Recruitment Hypothesis

Answer 24

Stepwise Assembly - transcription activators function by stimulating PIC formation or as bridging factor to create PIC (one by one they bind to promoter Recruitment Hypothesis - states that activators and coactivatorsss function to recruit a preformed holoenzyme-GTF complex to the promoter (meaning buo na siya bago magbind sa promoter)

Question 25

What does polycistronic mean?

Answer 25

In bacteria, proteins are synthesized in just one strand

Question 26

Promoters with both TATA and Inr (Initiation Sequence) are more actively transcribed. True or False?

Answer 26

True

Question 27

Differentiate Rho-factor independent from Rho-factor dependent

Answer 27

Rho-factor Independent - binds to G-C rich region, allows formation of a self-complimentary hairpin loop that contains UUUUs after it Rho-factor dependent - binds to C rich region containing an ATP-dependent Helicase that separates DNA from RNA

Question 28

What is the probable termination sequence in eukaryotes

Answer 28

AAUAAA

Question 29

Least tightly bound histones

Answer 29

H1

Question 30

Action of Actinomycin D

Answer 30

lodges between G-C pairs and effectively stops transcription

Question 31

What is the action of Rifampacin?

Answer 31

binds to beta subunit of RNAP inhibiting formation of initiation complex

Question 32

What is the action of Quinolones?

Answer 32

Inhibits DNA gyrase (stops replication and transcription)