Transcription

Question 1

α2ββ’σ RNA polymerase ___________

Answer 1

holoenzyme

Question 2

α2ββ’ Core polymerase
Synthesizes RNA but unable to bind to __________

Answer 2

promoters

Question 3

σ Binds the holoenzyme to promoter ___________

Answer 3

sequence

Question 4

ββ’ Both contribute to ___________ site

Answer 4

active

Question 5

β’ Binds to _________ template

Answer 5

DNA

Question 6

β Binds to ______ nucleotides

Answer 6

RNA

Question 7

α Essential for assembly of _______
subunits

Answer 7

enzyme

Question 8

RNA polymerase moves along the template strand, producing an RNA copy of the _____________ ___________ strand.

Answer 8

complementary, nontemplate

Question 9

The RNA transcript is both transcribed and translated in the ______ direction.

Answer 9

5’→3’

Question 10

The 5’ end of the transcript corresponds to the _________ end of the polypeptide

Answer 10

N-terminal

Question 11

First step in initiation in prokaryotes

Answer 11

RNA polymerase holoenzyme binds to the promoter region and separates the DNA strands, creating an open promoter complex.

Question 12

in the secod step of initiationThe first and second RNA nucleotides bind to the RNA polymerase and to the +1 and +2 bases, respectively, at the transcription start site. The two nucleotides are then linked by a __________

Answer 12

phosphodiester bond

Question 13

In the third step of initiation, __________ ________ begins to move along the template strand, adding additional nucleotides to the growing RNA chain.

Answer 13

RNA polymerase

Question 14

in prokaryotes, The RNA polymerase initiates the mRNA synthesis almost always with a __________.

Answer 14

purine

Question 15

what subunit is released, which completes initiation?

Answer 15

sigma (σ)

Question 16

Where is the transcription promotor region in a prokaryotic cell?

Answer 16

+1 start site

Question 17

the -35 region and the -10 region on the promoter bind to which subunit of RNA polymerase holoenzyme in prokaryotic cells?

Answer 17

sigma σ

Question 18

in elongation, the a2BB’ moves along the template strand synthesizing RNA to what end?

Answer 18

3’

Question 19

In elongation, as the core polymerase moves along the DNA, the double helix is unwound and then what?

Answer 19

it is rewound behind the advancing polymerase

Question 20

what is the error rate in the growing RNA chain with wrong nucleotides in the
RNA?

Answer 20

1 in 10,000

Question 21

to prevent slowing transcription, what does the topiosomerase enzyme do?

Answer 21

it acts to remove DNA supercoils and relax the DNA ahead of the polymerase

Question 22

T or F: elongation has a rate of 20 to 50 nucleotides per second.

Answer 22

True

Question 23

termination of transcription occurs through two different types in prokaryotes

Answer 23

(1) Termination of transcription is determined by specific
sequences along the DNA called termination sites, or
(2) Termination of transcription occurs through binding of
a protein termination factor called rho (ρ).

Question 24

in termination in prokaryotes, inverted repeat sequences result in what type of structure in RNA?

Answer 24

hairpin or stem-loop

Question 25

rho factor (ρ) dependent termination unwinds the RNA:DNA hybrid behind the RNA polymerase and releases what?

Answer 25

the transcript

Question 26

what does RNA polymerase I do? in eukaryotes

Answer 26

transcribes major ribosomal
RNA genes; located in the nucleolus

Question 27

what does RNA polymerase II do? in eukaryotes

Answer 27

transcribes protein-coding
genes and therefore synthesizes mRNA

Question 28

what does RNA Polymerase III do? in eukaryotes

Answer 28

transcribes tRNA genes,
5S rRNA genes, and genes of other small RNAs

Question 29

are polymerase i, ii and iii used in prokaryotes?

Answer 29

NO. they are in eukaryotes

Question 30

which rna polymerase is the biggest? in eukaryotes

Answer 30

RNA POLYMERASE I

Question 31

In the core eukaryotic promoter, the TATA box binds to what subunit of general
transcription factor TFIID?

Answer 31

TBP

Question 32

this leads to the binding of RNA polymerase II and other general transcription factors after what happens?

Answer 32

Binding of TBP

Question 33

Genes that lack a TATA box can use what initiator element that includes the transcription start site to accurately initiate transcription?

Answer 33

(Inr)

Question 34

what 2 effects does the Mediator complex (M) have on initiation and elongation? in eukaryotic cells.

Answer 34

The Mediator complex (M) binds to general transcription factors and RNA polymerase II
and thereby helps to bring initiation.
Once elongation begins, the
Mediator complex (M) dissociates from the RNAP and GTFs.

Question 35

what DNA binding protein
-Consists of two perpendicular α-helices connected by a β-turn.
-The side chains of one α-helix fit into the major groove of the DNA

Answer 35

Helix-turn-helix motif

Question 36

what DNA binding protein
Consists of two antiparallel β-strands followed by an α-helix.
Zn 2+ ions are bound to amino acid side chains.
The α-helix inserts into the major groove of the DNA

Answer 36

Zinc finger motif

Question 37

what DNA binding protein
-Consists of α-helices from two different proteins that form a coiled coil.
-Extensions of the α-helices bind to the major groove

Answer 37

Leucine zipper motif

Question 38

A “cap” derived from ____ is added to the 5’ end

Answer 38

GTP

Question 39

Why is a DNA loop made?

Answer 39

to bring the enhancer-bound activator protein to the RNA polymerase

Question 40

What does a cap do?

Answer 40

(1) prevents exonuclease digestion
(2) helps with the binding of the mRNA to ribosomes

Question 41

What linkage does the exonuclease not recognize and cut out?

Answer 41

5’-5’ link

Question 42

he addition of ____________ groups to the 5’ end of a transcript is also an
essential step in mRNA maturation.

Answer 42

methyl (CH3)

Question 43

what link can the exonuclease see?

Answer 43

3’-5’

Question 44

Poly(A) addition to a ___________by poly(A)
polymerase follows a poly(A) signal sequence
AAUAAA

Answer 44

3’ end

Question 45

The additions of up to 200 _ residues help protect the 3’ end from exonuclease

Answer 45

A

Question 46

Spliceosomes recognize __________ sequences at the 5’ exon/intron junction and the branch site.

Answer 46

conserved

Question 47

mRNA splicing is carried out by spliceosomes, composed of several ______-protein
complexes called snRNPs

Answer 47

RNA

Question 48

In the splicing reaction, a covalently closed loop of RNA, the________, is formed by the
covalent attachment of the 5’ end of an intron to the branch site A.

Answer 48

lariat

Question 49

The lariat is formed by covalent attachments of what two ends?

Answer 49

the 5’ end of an intron to the branch site A

Question 49

The lariat is formed by covalent attachments of what two ends?

Answer 49

the 5’ end of an intron to the branch site A

Question 50

mRNA decay begins with the shortening of the poly(A) tail by a _________ enzyme.

Answer 50

deadenylase

Question 51

A decapping enzyme removes the 5’ cap. The mRNA is then degraded from _____ ends by 5’ and 3’ exonucleases.

Answer 51

both

Question 52

The initial rRNA transcripts of ___ are converted into smaller rRNAs of 18S, 5.8S, and 28S by the action of endo- and exonucleases.

Answer 52

45S

Question 53

what does a topoisomerase do in elongation? (prokayrotes)

Answer 53

it relaxes the double helix so RNA polymerase can move in a straight line

Question 54

polymerase i,ii and III are used in eukaryotes or prokaryotes?

Answer 54

eukaryotes

Question 55

TATA boxes are involved in prokaryotic transcription or eukaryotic?

Answer 55

eukaryotic

Question 56

make flashcards on page 18

Question 57

CPSF

Answer 57

binds to AAUAAA