Lecture 8 Flashcards
Prokaryotes have how many polymerase? Eukaryotes?
1, 3
What is the relationship between consensus sequence and promotor stregnth
the closer to the Consensus Sequence, the stronger the promoter
Determines how well genes are transcribed
consensus sequence
In the initiation of bacterial transcription, the ____ binds and recognizes the -10 and -13 regions, which causes a….
sigma factor, closed complex
Formation of an open complex in bacterial transcription is made by…
RNA poly opening up 2 DNA strands
When RNA polymerase releases the sigma factor, what occurs
bacterial transcription
What eukaryotic RNA polymerase transcribes 3/4 rRNAs
poly 1
What eukaryotic RNA polymerase transcribes the majority of the RNA in eukaryotic cells
poly 1
What eukaryotic RNA polymerase transcribes ribosomal RNA (rRNA) …except 5S rRNA
poly 1
What eukaryotic RNA polymerase transcribes mRNA and snRNA and LINE-1 transposons
poly 2
What eukaryotic RNA polymerase transcribes the most genes
poly 2
Alu and LINE-1 have what feature?
internal promoters
What eukaryotic RNA polymerase transcribes tRNA and 5SrRNA and Alu transposons
poly 3
What eukaryotic rna polymerases are specialized
poly 1 and 3
Bacterial and eukaryotic RNA polymerases have what in common?
similar general structure
Euk. RNA poly 1 has what transcript?
45S transcript
In Euk. RNA poly 1, the processing of rRNA in eukaryotes is that….
45S transcript gets put in ultracentrifuge, cleavage occurs, and left with 3 rRNAs
In euk. RNA poly 3, when processing tRNA precursor into tRNA what occurs
base modification in tRNA, endonuclease cleaves and exonuclease cleaves
What is a special feature of euk RNA poly 3?
RNase P
is an “ribozyme” the catalytic activity resides in the RNA
RNase P (in rna poly 3)
Amino acids are brought to the ribosome by…
tRNA
Amino acids are brought to the ribosome by…
tRNA
What is commonly found at a eukaryotic RNA pol II promotor
TATA box
25 nucleotides upstream to initiation of transcription
TATA box
25 nucleotides upstream to initiation of transcription
TATA box
With RNA poly 2 in eukaryotes, TFIID binds to the…
TATA box
is a complex of proteins that includes the TATA binding protein (TBP)
and several TBP-associated factors (TAFs)
TFIID
Is TFIID found in bacteria?
No
TFIID recruit other proteins that….
tether to the RNA polymerase to the TATA box
Initiation of RNA poly 2 transcription needs help by….
TFIID
TFIID two roles with RNA poly 2 transcription
acts as a helicase to form open complex and phosphorylates CTD of RNA poly 2
releases the
RNA polymerase from the tether made up by
transcription factors and the tether falls apart
CTD phosphorylation
CTD phosphorylation causes a ___ and forms an ____
shape change and forms an open complex
The eukaryotic initiation of transcription is known as
basal transcription
Heat the DNA to break the hydrogen bonds
–> the two strands come apart (“denatured DNA”)
Then add mRNA and let it cool slowly
Hybridization of mRNA to DNA
In Hybridization of mRNA to DNA because DNA/RNA H bonds are stronger than DNA/DNA, you get an….
R loop
Where RNA binds to 1 DNA strand and single stranded DNA
R loop
A single “R Loop” was seen for…
most bacterial genes and some eukaryotic genes
An intro + mRNA equals…
mRNA bound to DNA with multiple R loops and intron loops
Discontinuous regions of DNA that are complementary to mRNA, spliced out
intron
Introns occur the most in what genes?
eukaryotic
Who discovered introns
Richard Roberts and Phil Sharp
introns occur in….
introns are spliced out when?
pre-mRNA
before mature mRNA leaves nucleus
Three different mechanisms for RNA splicing…
- Group I intron splicing
- Group II intron splicing
- Spliceosome
What can self-splice?
Group 1 and 2 intro splicing
discovered by Tom Cech (Nobel Prize)
self-splicing