Ch. 17b Eukaryotic Transcription (Exam 2)

Question 1

What’s the difference between prokaryotic transcription and eukaryotic transcription in terms of where they take place?

Answer 1

Prokaryotic = DNA template

Eukaryotic = chromatin template

Question 2

Define transcription factor.

Answer 2

Any protein needed to start transcription but is not part of the RNA polymerase

Question 3

Aside from chromatin being opened and not condensed, what must happen to the nucleosome octamers before transcription can occur?

Answer 3

They must be moved or removed from promoter sequences

Question 4

What is the difference between prokaryotic and eukaryotic transcription in terms of how their RNA polymerase activity?

Answer 4

Prokaryotic = RNA polymerase can read DNA

Eukaryotic = RNA polymerase canNOT read DNA

Question 5

What are cis-acting elements?

Answer 5

Non-coding regions that regulate transcription of nearby genes

Question 6

What are basal transcription factors?

Answer 6

Transcription proteins that bind to certain sites, like the promoter, to activate transcription

Question 7

Define core promoter.

Answer 7

Region containing all binding sites necessary for RNA polymerase to bind and function

Question 8

Does RNA polymerase extend to the upstream region of the promoter?

Answer 8

No, but it does bind to the start point of transcription, which is a little bit downstream of the promoter

Question 9

What are the 3 RNA polymerase classes?

Answer 9

I, II, III

Question 10

In RNA polymerase II, you will find these types of RNA…

Answer 10

mRNA & some small RNAs

Question 11

Are transcription factors or RNA polymerases responsible for recognizing the promoters in eukaryotes?

Answer 11

Transcription factors

Question 12

How do basal transcription factors help RNA polymerase?

Answer 12

Basal transcription factors create a 3D structure to provide a target for the RNA polymerase i.e. they act as a liaison from promoter to RNA polymerase

Question 13

What is an enhancer?

Answer 13

Non-coding sequence that enhances the transcription process and the likelihood that a gene will be transcribed

Question 14

What are housekeeping genes (constitutive promoters)?

Answer 14

Promoters constitutively expressed and needed in all cells

Question 15

In terms of their amount of subunits, what do RNA polymerases I-III have in common?

Answer 15

They all have about 12 subunits

Question 16

RNA polymerase I synthesizes rRNA in the…

Answer 16

Nucleolus

Question 17

RNA polymerase II synthesizes mRNA in the…

Answer 17

Nucleoplasm

Question 18

RNA polymerse III synthesizes small RNAs in the…

Answer 18

Nucleoplasm

Question 19

How are RNA polymerases in prokaryotes and eukaryotes similar in terms of subunit and function?

Answer 19

Subunit: 2 largest homologous to the beta & beta-prime subunits in bacteria

Function: similar/same function contained in basal transcription factors

Question 20

The largest subunit in RNA polymerase is…

Answer 20

Carboxyl-terminal domain (CTD)

Question 21

What exactly is the CTD?

Answer 21

Multiple repeats of a consensus sequence on seven amino acids

Question 22

What are 3 uses for CTD?

Answer 22

1) Initiation
2) Transcription elongation
3) Everything related to mRNA processing

Question 23

What is another name for the basal transcription factors that bind to the promoter to direct RNA polymerase binding?

Answer 23

Preinitiation complex

Question 24

What is a downstream promoter element (DPE)?

Answer 24

Common component of RNA polymerase II promoters without a TATA box

Question 25

What does the core promoter of RNA polymerase II typically include (HINT: 2 things)?

Answer 25

1) Initiator (inr) 2) Either TATA box or DPE

Question 26

What is a TATA box?

Answer 26

A-T rich octamer capable of defining the direction of transcription and indicating the DNA strand that needs reading

Question 27

What is the TATA-binding protein (TBP)?

Answer 27

Component of positioning factor needed in all RNA polymerases for binding to the promoter

Question 28

You will typically find TBP bound to the TATA box...

Answer 28

In the minor groove of DNA

Question 29

Basal transcription factors for RNA polymerase II are notated as...

Answer 29

TFII + whatever letter A-J

Question 30

The first step of initiation requires the binding of this basal transcription factor to the TATA box or initiator...

Answer 30

TFII D

Question 31

Initiation actually begins when...

Answer 31

RNA polymerase II binds to the TFII D complex

Question 32

How does the TATA box-containing promoter become active?

Answer 32

TBP subunit of TFIID directs binding to the TATA box

Question 33

What happens when the TFIID directs binding to the TATA box?

Answer 33

TFIIB contacts the minor groove (downstream) and major groove (upstream), which allows recognition from RNA polymerase

Question 34

How is promoter melting (DNA unwinding) useful?

Answer 34

It allows transcription to start

Question 35

What 3 TFII allow for promotor melting?

Answer 35

B, E, & H

Question 36

When does elongation occur?

Answer 36

After the formation of the preinitiation complex when RNA polymerase is released from the other transcription factors

Question 37

This chemical process, involving the addition of phosphorus, acting on the carboxyl-terminal domain (CTD) is required for promoter clearance and elongation...

Answer 37

Phosphorylation

Question 38

Interrupted genes require further processing to become...

Answer 38

Functional and mature

Question 39

During transcription, the 5' end is capped, but the 3' end is...

Answer 39

Polyadenylated

Question 40

Where in the cell is RNA translated into proteins?

Answer 40

Cytoplasm

Question 41

Why do transcription and translation occur at the same time in prokaryotes but not eukaryotes?

Answer 41

Prokaryotic genomes are much simpler

Question 42

How is termination signaled in RNA polymerase transcription?

Answer 42

mRNA 3' end formation

Question 43

What is the purpose of the AAUAAA sequence?

Answer 43

To signal cleavage of polyadenylated 3' end of mRNA

Question 44

What are the 3 purposes of the poly(A) tail?

Answer 44

1) Controlling mRNA stability 2) Facilitating nuclear export of mRNA 3) Influencing translation