TRANSCRIPTION Flashcards
1
Q
RNA consist of what strand of ribonucleotides
A
Single stranded
2
Q
which is more reactive RNA or DNA
A
RNA
3
Q
What differentiates RNA from DNA
A
RNA has an OH on the 2’ C of its sugar
4
Q
what are the structure of RNA
A
RNA folds from primary to secondary structure.
5
Q
synthesis of RNA starts where and ends
A
starts atv5’end and ends at 3’ end
6
Q
which is easily degraded RNA or DNA
A
RNA
7
Q
Function of rRNA
A
structural and functional component of ribosome in cytoplasm
8
Q
which RNA carries genetic code for proteins
A
Messenger RNA
9
Q
function of smalll nuclear RNA (snRNA)
A
Processing of pre-mRNA
10
Q
which RNA processes and assembles rRNA
A
small nucleolar RNA (snoRNA)
11
Q
function of MicroRNA (miRNA)
A
inhibits translation of mRNA
12
Q
which RNA triggers degradation of other RNA molecule
A
small intefering RNA (siRNA)
13
Q
which RNA assists destruction of foreign DNA
A
CRISPR RNA (crRNA)
14
Q
which RNA has the eukaryotic nucleus and cytoplasm Varity of function
A
Long noncoding RNA (IncRNA)
15
Q
What is the synthesis of an RNA molecule from a DNA Template
A
Transcription
16
Q
Transcription contains
A
The DNA template
The substrates for transcription (4 RIBONUCLEASIDE TRIPHOSPAHTE)
The transcription apparatus
17
Q
The template of RNA has
A
transcribed strand
transcription unit
18
Q
all circular RNA are transcribed from
A
DNA
19
Q
examples of RNA transcribed in both eukaryotic and prokaryotic cell
A
mRNA, rRNA, tRNA
20
Q
examples of RNA transcribed in eukaryotes
A
pre-mRNA
snRNA
snoRNA
miRNA
siRNA
piRNA
21
Q
which RNA is produced only in prokaryotes
A
CRISP RNA (crRNA)
22
Q
In the EM, which RNA gene undergoes transcription resembling Christmas tree
A
nuclear ribosomal RNA
23
Q
The transcribed strand is also known as
A
template strand or antisense strand or non coding strand
24
Q
Th upper strand of the RNA template is called
A
non-template strand or coding strand
25
RNA is synthesized in which direction
5' to 3'
26
which strand does RNA polymerase use as template strand and how is it read
lower strand, read from 3' to 5'
27
How often are rNTPs added to the 3'end of RNA molecule
one at a time
28
Transcription produces an RNA molecule that is---- to the strand
complementary and antiparallel to the template strand
29
Adjacent genes in the chromosomes can be transcribed from which strands
opposite strand
30
does the transcription unit contain a promoter
NO
31
Transcription unit comprises of
Transcription initiation site
RNA-coding sequence
Terminator
32
The transcription unit extends from
transcription initiation site to the transcription termination site
33
what is the building blocks of RNA
Ribonucleoside triphosphate (rNTPs)
34
does initiation of RNA synthesis require primer
NO
35
What transcription apparatus uses a number of accessory protein to drive transcription
RNAP (polymerase)
36
RNAP consists of how many subunits?
5 subunits
37
what are the subunits of RNAP
Two copies of alpha
Single copy of beta
Single copy of beta prime
single copy of omega
38
what controls the binding to the promoter so initiation begins at the transcription initiation site
sigma factor
39
what binds to the sigma factor
RNA polymerase core binds to the sigma factor and holoenzyme is active
40
Holoenzyme binds to what to initiate transcription
binds to the promoter and initiate transcription
41
what are the 3 distinct classes of RNA polymerases
RNAP I, RNAP II, RNAP III, (RNAP IV & V IN PLANTS)
42
Each set of RNA polymerases have set of accessory protein called
transcription factors
43
which RNAP encodes large rRNAs
RNA Polymerase I
44
which RNAP encodes Pre-mRNA, some snRNAs, snoRNA, miRNAs
RNA polymerase II
45
Which RNAP encodes tRNAs, small rRNAs, some
snRNAs, some miRNA
RNA polymerase III
46
During initiation what happens
the transcription apparatus assembles at the promoter and initiate RNA synthesis
47
what happens during ELongation
DNA is threaded through RNA polymerase and RNAP unwinds DNA, adds new ribonucleotide one at a time to3'end of transcript
48
the release of RNA product from DNA template is in which step
Termination
49
What are the steps required to begin RNA synthesis
>Promoter recognition by RNAP
* Formation of a transcription bubble
* Formation of the first phosphodiester bonds
between rNTPs
* Movement of the RNAP away from the promoter
50
Promoter determines
where, when, and to what
extent a gene will be transcribed
51
short DNA sequences that possess
considerable similarity among genes are called
Consensus sequence
52
Promoters also serve as
binding site for RNAP or protein involve din transcription
53
where is a typical consesnus sequence located
at the upstream of the initiation site in bacterial promoters
54
what are the consensus sequences often found in bacterial promoters
-10 TATAAT
-35 TTGACA
55
TATAAT is also known as
Pribnow box
56
TATAAT, TTGACA are recognized by
RNAP holoenzyme plus sigma factor
57
The transcription initiation site is determined by
the position of the consensus sequences.
58
The orientation and spacing of the consensus
sequences in the promoter determines
which DNA strand will serve as template and so
determine the direction of transcription.
59
How does the holoenzyme initiate transcription
By unwinding the double stranded DNA
60
Which strand serves as the first nucleotide in the RNA molecule
the rNTP complementary to the base at the start site
61
what is released as the RNA polymerase moves past the promoter
SIgma factor
62
when is RNA transcription initated
when core RNA polymerase binds to the promoter with the help of sigma
63
what creates a RNA nucleotide during initation
two phosphate group cleaved from each subsequent rNTP, this adds to 3' end
64
After initiation, what does RNAP do to its shape
it changes conformation so that it no longer binds to consensus sequences in promoter and begin transcribing
65
what happens during transciption bubble
1. 18 nucleotides of DNA template unwonds
2. 8 nucleotides of RNA is base paired with template strand
66
As transcription bubble moves, supercoiled occur which is released by
topoisomerases
67
transcriptional pausing plays a role in
coordinating transcription and translation
68
transcriptional pausing results from
secondary structures or specific
sequences (or presence of nucleosomes in
eukaryotes)
69
Transcriptional pausing may cause RNA to move backwards/forward
backwards
70
what does RNAP do when misincorporation occur
RNAP backtracks, cleaves out the last 2 nucleotides,
then proceeds transcribing forward
71
Define Rho-dependent termination
uses rho (ρ) factor
72
describe Rho-independent termination
hairpin structure formed by inverted repeats, followed by a string of
uracils
73
describe Polycistronic mRNA:
bacteria frequently transcribe a group of genes into a single RNA molecule
74
How does RHO cause termination intranscription
1. Rho binds to the rut site and moves towards 3' end
2. RNAP encounters a terminator sequence and pauses. This allows Rho to catch up
3. Rho using Helicase unwinds RNA-DNA hybrids and brings transcription to a stop
75
How does eukaryotic transcription differ from bacterial transcription in RNAP
eukaryotic RNAP employs multiple classes
76
which is larger eukaryotic promoters or bacterial promoters
larger and more complex
77
what must occur in eukaryote before Transcription
Chromatic modification
78
chromatin contianing transcribed genes in less densely packed regions are called
Euchromatin
79
what is an important regulatory process between euchromatin and heterochromatin in eukaryote
interconversion
80
RNAPII promoters contain
core promoter and a
regulatory region
81
the core promoter overlaps
transcription initiation site
82
core promoter and regulatory region both contain what necessary for transcription
consensus sequences
83
TATA box is what type of promoter
core promoter element
84
Where are RNAP II promoters located in eukaryote
-25 to -30 bp upstream of inittaiion site
85
TATA box is bound by
TATA binding protein (TBP) subunit of Trnascription Factor II D (tffiid)
86
Types of transcription factors
transcriptional activators and transcriptional repressors
87
regulatory region promoter contains
several different types of promoter elements (consensus sequences)
88
where are enhancers located
distance from the genes it regulates
89
what happens to the chromatin between the promoter and enhancer
oops out so the proteins bound to each can interact
and thus regulate transcription
90
Silencers act
negatively regulate transcription by
binding transcriptional repressors
91
RNAP III genes contain
internal promoters that are downstream of the start site and
so are transcribed into the RNA products.
92
RNAP II + general transcription factors form
a pre-initiation complex (PIC)
93
TATA binding protein binds to which grooove of DNA
Minor groove straddling double helix like a saddle
94
Afrer RNA are synthesized, what happens to RNAP II
moves away from the promoter
95
Mechanism of RNAP I
uses a termination factor similar to rho
but it binds to a DNA sequence downstream of
the terminator.
96
Mechanism of RNAP II
termination does not occur at specific
sequences.
97
Mechanism of RNAP III
transcribes the terminator that adds a
string of uracils in RNA.
98
Similarities of Transcription in Archaea to Eukaryotes
RNAP in archaea are more similar in eukaryote than Eubacteria
Arcahaea has a TATA box and TATA binding protein
