Gene Expression: Transcription

Question 1

what is the simplified expression of the central dogma of molecular biology?

Answer 1

dna makes RNA makes protein

Question 2

transcription is the making of __ from a __ template

Answer 2

RNA; DNA

Question 3

only ___ (type of RNA) gets translated into protein molecules

Answer 3

mRNA

Question 4

transcription is catalyzed by a large enzyme common to all life forms ____

Answer 4

rna polymerase

Question 5

transcription proceeds through 3 steps

Answer 5

1. initiation
2. elongation
3. termination

Question 6

what happens in initiation of transcription?

Answer 6

RNAP binds to region of DNA called a promoter and the DNA in that region opens up so RNAP can begin transcription

Question 7

what is a promoter?

Answer 7

a base sequence upstream of the coding portion of a gene containing recognition sites for RNAP to bind

Question 8

T/F RNAP requires a primer to initiate polymerization.

Answer 8

false

Question 9

in bacteria, many dna promoters have recognition sites called the -10 and -35 region because ___

Answer 9

they are roughly 10 and 35 nucleotides upstream to the start site

Question 10

the first nucleotide (start site) of a transcribed DNA sequence (gene) is denoted as ___

Answer 10

+1

Question 11

T/F RNAP is a multisubunit complex

Answer 11

t

Question 12

role of alpha subunit

Answer 12

assembly of core enzyme, interacts with regulatory factors

Question 13

role of the beta subunit

Answer 13

takes part in all stages of catalysis

Question 14

role of beta 1 subunit

Answer 14

binds to DNA , takes part in catalysis

Question 15

role of omega (w) subunit

Answer 15

restore denatured polymerase to its native form

Question 16

role of the sigma 70 subunit

Answer 16

promoter recognition

Question 17

the entire subunit complex of the RNAP is called the __

Answer 17

holoenzyme

Question 18

RNAP without the sigma subunit is called the ___

Answer 18

core enzyme

Question 19

the core enzyme contains the ___

Answer 19

active site

Question 20

in bacteria, sigma factors recognize and bind ___, targeting ___ to site

Answer 20

promoters; RNAP

Question 21

core RNAP is capable of carrying out ___, but it cannot ___

Answer 21

transcription; recognize and bind promoter DNA

Question 22

the holoenzyme RNAP is capable of recognizing and binding ____ and when it does, it forms a ___ complex

Answer 22

promoter dna; transcription complex

Question 23

the holoenzyme is targeted to the gene promoter by the _-

Answer 23

sigma factor

Question 24

sigma factors enable recognition of ___

Answer 24

promoter sequence

Question 25

sigma factors also play a primary role in converting ___ into ___ at the promoter (open-complex formation)

Answer 25

dsdna; Ssdna

Question 26

T/F most bacteria have multiple sigma factors, all recognizing their own promoter sequence

Answer 26

t

Question 27

location of transcription in eukaryotes

Answer 27

nucleus

Question 28

T/F DNA leaves the nucleus in eukaryotes

Answer 28

false

Question 29

what are the 3 RNA polymerases in eukaryotes and functions?

Answer 29

1. RNAP 1: makes rRNA 2. RNAP 2: makes mRNA 3. RNAP 3: makes tRNA

Question 30

alpha--Amanitin is made by ____ and inhibits ___

Answer 30

poisonous mushrooms; RNAP 2

Question 31

which has more subunits, eukaryotic RNAP or bacterial?

Answer 31

eukaryotic

Question 32

T/F eukaryotic RNAP has a sigma factor

Answer 32

f

Question 33

in eukaryotes, proteins called called transcription factors bind to ___ and recruit the ___

Answer 33

promoter DNA; RNAP 2

Question 34

many eukaryotic promoters have a sequence called a ___ that plays the role of a promoter

Answer 34

TATA box

Question 35

when the TATA is recognized by a TF, allowing other TFs to bind, forming a ___

Answer 35

transcription complex

Question 36

once made, a transcription complex recruits ___ to form a__

Answer 36

RNAP 2; initiation complex

Question 37

some TFs allow eukaryotes to control the level of ___

Answer 37

gene expression

Question 38

some TFs can be activators or repressors: can increase or decrease the likelihood of forming a ___

Answer 38

ignition complex

Question 39

activator/repressor TFs bind to __ or __ regions upstream of the DNA strand

Answer 39

enhancer; silencer

Question 40

the ___ of DNA is what allows transcription factors at distant binding sites to work

Answer 40

flexibility

Question 41

____ catalyses the initiation and elongation of RNA

Answer 41

RNAP

Question 42

RNAP requires what 3 components?

Answer 42

1. a template 2. activated precursors 3. Mg or Mn cofactor

Question 43

what is the template for RNAP?

Answer 43

one of the DNA strands

Question 44

the template strand sequence:

Answer 44

complement of that of the RNA transcript

Question 45

the coding strand sequence :

Answer 45

same as the RNA transcript, but T in place of U

Question 46

what are the activated precursors?

Answer 46

the buliding blocks of the RNA product (ribonuclioside triphosphates)

Question 47

Mg stabilizes ___ and __ on incoming nucleotides

Answer 47

beta and gamma phosphates

Question 48

after the promoter region, RNAP ___ a 17-bp segment of the DNA double helix so that nucleotides on the template strand can direct the __

Answer 48

unwinds; synthesis of the RNA product

Question 49

elongation takes place at __ that move along the DNA template

Answer 49

transcription bubbles

Question 50

what are the 2 main stop singles for transcription in bacteria?

Answer 50

1. rho-independent termination | 2. rho-dependent termination

Question 51

what is rho independent termination?

Answer 51

the stop signal is an RNA hairpin (series of bases that form a stable stem and loop) followed by several Us

Question 52

what is rho-dependent termination?

Answer 52

a rho protein binds the nascent RNA strand and pulls it away from RNA polymerase and DNA template

Question 53

t/f eukaryotic mRNA is highly processed

Answer 53

true

Question 54

pre-mRNA acquire a ___ cap and a __ tail and will be spliced by __

Answer 54

guanine 5' cap' and poly A 3'tail ; introns

Question 55

function of guanine cap

Answer 55

prevent deflation and ease translation

Question 56

function of the poly A tail

Answer 56

prevent degradation and ease translation

Question 57

poly A polymerase adds about 250 ___ residues to an mRNA after being cleaved after transcription

Answer 57

adenylate

Question 58

introns can vary between __ and __ nucleotide

Answer 58

50--10 000`

Question 59

a mixture of __ and __ form small nuclear ribonucleoproteins (snRNPs)

Answer 59

proteins and small nuclear RNA molecules

Question 60

assembly of 5 snRNPs forms a __

Answer 60

spliceosome

Question 61

function of spliceosome

Answer 61

catalyze splicing