Module 8 Flashcards
________: encodes sequence of amino acids in polypeptide
__________: major component of ribosomes
__________: carries amino acids to ribosomes during protein synthesis
_________: helps remove introns from mRNA molecules (eukaryotes)
_____________: regulate gene expression by binding to mRNA molecules (eukaryotes)
_____________: (siRNA) double-stranded regulatory RNA, interacts with mRNA (eukaryotes)
___________: interacts with telomerase, template for elongating telomeres (eukaryotes)
mRNA
rRNA
tRNA
snRNA
miRNA
siRNA
telomerase RNA
___________ is the synthesis of a single-stranded RNA molecule by RNA
polymerase
transcription
What does RNA polymerase use to
assemble a complementary, antiparallel strand of ribonucleotides?
What is complementary to the template strand?
the template (non-coding) strand of the DNA
the coding strand
Is DNA or mRNA associated with Regulator, Promoter, Terminator?
Is DNA or mRNA 5ʹ and 3ʹ UTR, RBS (ribosomal binding sequence), Start and Stop
Codons, coding region?
DNA
mRNA
Where is the promoter located?
upstream to the start of transcription
what holds
the information needed to
synthesize a protein product?
coding region
Where is the terminating region located?
downstream to the coding segment
What enzyme is responsible for transcribing a DNA sequence into a complementary RNA sequence?
What is the enzyme composed of?
rna polymerase
core enzyme that binds a sixth subunit, called the sigma subunit
T/F core enzyme:
cannot transcribe RNA from a DNA template but can bind the promoter or initiate RNA synthesis without the subunit
FALSE, core enzyme:
▪ CAN transcribe RNA from a DNA template but CANNOT bind the promoter or initiate RNA synthesis without the subunit
RNA polymerase is attracted to promoters by what?
the presence of consensus
sequences
Rho-independent (aka intrinsic):
mRNA forms what?
Rho-dependent: rho (ρ) protein
binds what in mRNA?
hairpin/ stem-loop
rho utilization (or rut) site in mRNA
Which of the following is not shared between Rho
dependent and Rho-independent termination of
transcription?
a) both are found in bacteria
b) Rho utilization site (rut)
c) poly-U tract at mRNA 3’ end
d) poly-A tract in template strand
e) formation of hairpin/stem-loop structure
T or F Eukaryotic transcription is more complex than bacterial transcription
True
eukaryotic DNA associated with
many proteins to form what?
chromatin
heterochromatin vs. euchromatin
heterochromatin is tightly packed, and transcriptionally inactive chromatin is loosely packed and transcriptionally active
The promoters for RNA pol II genes are highly __________ with different overall lengths and number and types of consensus sequences
diverse
RNA Polymerase I – (how many?) rRNA
▪ RNA Polymerase II – __RNA and most snRNA for spliceosomes, also miRNA and siRNA
▪ RNA Polymerase III – __RNA (plus miRNA, siRNA, one snRNA and one rRNA)
- 3 rRNA
- mRNA
- tRNA
most common Eukaryotic Promoter Elements
the TATA box, or the Goldberg-Hogness box, 5’-TATAAA-3’, located at about position −25 (upstream of start codon)
- A CAAT box is often found near the?
- A GC-rich box (consensus 5-GGGCGG-3) is located at?
- −80 position
- −90, or further upstream
- initial committed complex: TFIID
(transcription factor IID) binds at promoter - Minimal initiation complex: _____ ___________ joins along with three other TFII proteins
- ____________ complex: two more TFII
proteins join
- initial committed complex
- RNA polymerase
- Preinitiation complex
what do Enhancer sequences do?
increase the level of transcription of specific genes
DNA elements that act at a distance
to repress transcription of their target genes
Silencer sequences
what transcribes a gene
past a poly(A) signal sequence?
RNA polymerase II
Allosteric model: After passing the polyA signal sequence, RNA polymerase II is destabilized due to what?
the release of elongation factors or the binding of termination factors. Termination occurs.
Torpedo model: An exonuclease binds past the polyA
sequence in mRNA that is still being transcribed and
degrades it in a 5’ to 3’ direction. Exonuclease
catches what?
RNA polymerase and ‘bumps’ it off.
In ______________ especially, we refer
to pre-mRNA (pre-processing) and mature mRNA (postprocessing).
eukaryotes
T or F The 5ʹ cap is a modified guanine nucleotide
true
five Functions of the 5’ Cap and 3’ poly-A tail
- Protection of mRNA
- Facilitating transport of mRNA out of nucleus
- Enhancing translation efficiency
- Facilitating subsequent intron splicing (G cap)
Introns generally contain three short sequences what are they?
5’ splice site
3’ splice site
branch site
in intron splicing, the 5’ splice site guanine
forms bond with branch site ________, resulting in
formation of ‘lariat’ structure
adenine
which group of introns are
capable of splicing themselves?
group I and group II introns are
capable of splicing themselves
group I and II introns are classified
as?
ribozymes (RNA enzymes)
Large eukaryotic genomes often express more proteins than there are genes in the genome due to what? alternative pre-mRNA processing
alternative pre-mRNA processing
what is Alternative splicing?
pre-mRNA can be spliced in different patterns in
different cell types
- Alternative __________: can initiate transcription at distinct +1 start points in different cell types
Alternative _____________: varying localizations of polyadenylation can produce
different mature mRNAs
- alternative promoters
- Alternative polyadenylation
one of many eukaryotic genes
that features alternative splicing
rat tropomyosin
single gene responsible for how many mRNA
transcripts?
9
- All RNAs are produced by what?
- Only _____ is translated into protein
- transcription
- mRNA
