RNA Part 2

Question 1

Key differences in transcription between eukaryotes and prokaryotes

Genes and their spacing?

Answer 1

Eukaryotes typically have more genes that are spaced further apart

Question 2

Key differences in transcription between eukaryotes and prokaryotes

RNA pol?

Answer 2

Eukaryotes have 4 RNA polymerases
Prokaryotes have 1

Question 3

Key differences in transcription between eukaryotes and prokaryotes

What do eukaryotes have the prokaryotes dont?

Answer 3

Nucleus

Question 4

How is DNA in eukaryotes packaged?

Answer 4

Into chromatin

Question 5

In eukaryotes, _ are exported from the nucleus prior to translation

Answer 5

Transcripts

Question 6

What are the 3 RNA polymerases

Answer 6

RNA pol I
RNA pol II
RNA pol III

Question 7

RNA pol I responsibility

Answer 7

Recruits the ribosome and rRNA
rRNA genes except 5s

Question 8

RNA pol II responsibility?

Answer 8

Transcribes protein-coding genes and a variety of noncoding RNAs

Question 9

RNA pol III responsibility

Answer 9

tRNAs, some snRNAs, 5s rRNA

Question 10

Most eukaryotes have multiple if not many, _ copies of rDNA genes

Answer 10

tandem

Question 11

RNA pol II recruitment and activation

What is a preinitiation complex (PIC) ?

Answer 11

A number of general transcription factors cooperate to form the PIC

Question 12

What does the PIC do?

Answer 12

PIC recruits additional transcription factors and RNA pol II

Question 13

How do you enable elongation?

Answer 13

A kinase phosphorylates RNA pol II and other proteins to enable elongation

Question 14

What does the architecture of RNA pol III recruitment and activation depend on?
What does that mean?

Answer 14

Depends on the promoter type.
Different promoters regulate different genes

Question 15

What is RNA pol II regulated by?

Answer 15

RNA pol II is regulated at multiple steps by carboxyl-terminal domain (CTD) posttranslational modification

Question 16

How many models did we go over for how RNA pol II terminates

Answer 16

2

Question 17

First model of RNA pol II termination?

Answer 17

An exonuclease causes RNA pol II to dissociate

Question 18

Second model of how RNA pol II terminates?

Answer 18

The cleavage of mRNA causes a conformational change in RNA pol II

Question 19

What are RNA pol II transcripts capped with at the 5’ end?

Answer 19

Capped with 7-methylguanosine to provide protection

Question 20

What does 5’ end capping involve?

Answer 20

Capping involves the sequential action of 3 enzymes associated with the CTD

Question 21

How are the 3’ end of RNA pol II transcripts protected?

Answer 21

Protected by polyadenylation, poly-A binding proteins come in and protect the 3’ end

Question 22

Addition of the poly-A tail involves _ of the mRNA followed by polyadenylation

Answer 22

Cleavage

Question 23

mRNA splicing

What acts at the 5’ splice junction?

Answer 23

u1 small nuclear ribonucleoprotein
snRNP

Question 24

mRNA splicing

Normal splicing involves specific pairing between

Answer 24

U1 snRNA and the splice site

Question 25

# mRNA splicing What could disrupt splicing

Answer 25

Mutations at the splice site

Question 26

What can suppress some splice site mutations?

Answer 26

Secondary mutation in the U1 snRNA

Question 27

What do U1 and U2 snRNPs enable?

Answer 27

They enable the formation of the spliceosome and intron excision

Question 28

How does splicing proceed?

Answer 28

Through a series of transesterification reactions

Question 29

What organisms have self-splicing introns?

Answer 29

Some bacteria, viruses and nuclear-encoded organellar genes

Question 30

What are self-splicing introns?

Answer 30

Ribozymes

Question 31

What does alternative splicing produce?

Answer 31

Related but distinct protein isoforms

Question 32

In eukaryotes, how can a single gene produce a variety of transcripts?

Answer 32

Splicing makes this possible

Question 33

A single pre-mRNA that contains exons and introns can be _ in a myriad of patterns

Answer 33

spliced

Question 34

What enables the formation of spliceosome and intron excision?

Answer 34

U1 and U2 snRNP

Question 35

Splicing proceeds through a series of _ reactions

Answer 35

Transesterification

Question 36

What organisms have self splicing introns

Answer 36

Some bacteria, viruses and nuclear encoded organellar genes

Question 37

Self-splicing introns are _

Answer 37

ribozymes

Question 38

How can you produce distinct protein isoforms?

Answer 38

Alternative splicing

Question 39

In eukaryotes, how is it possible for a single gene to produce a variety of transcripts

Answer 39

Splicing makes this possible

Question 40

a single pre-mRNA that contains exons and introns can be spliced in a myriad of _

Answer 40

Patterns

Question 41

There are _ mechanisms for mRNA decay in eukaryotes

Answer 41

multiple

Question 42

_ or _ RNA can result in gene silencing

Answer 42

Exogenous or ectopic

Question 43

How are small interfering RNAs (siRNAs) produced ?

Answer 43

By hairpin or double stranded RNAs

Question 44

_ processes siRNAs to enable them to complex with _

Answer 44

Dicer Argonaute (Ago)

Question 45

The Ago complex is further processed and is able to target the _ _

Answer 45

Complementary mRNA