Molecular (Kaplan) 2 Flashcards
What does RNA pol I do in eukaryotic cells? Where is it located?
Produces all ribosomal subunits, EXCEPT for the 5S subunit. Nucleolus.
What does RNA pol II do?
hnRNA/mRNA and some snRNA
RNA pol III?
tRNA and 5S ribosomal subunit
What must bind to the promoter before RNA polymerase to begin transcription in prokaryotes? In eukaryotes?
σ; transcription factors
What factor is sometimes required to terminate transcription in prokaryotes? In eukaryotes?
ρ; unknown
What drug is used to prophylax against meningitis in close contacts of a pt?
Rifampin
What is the other main use of rifampin?
TB
Mech of rifampin?
Inhibits prokaryotic RNA polymerase
What toxin inhibits eukaryotic mRNA synthesis? What RNA pol does it inhibit then?
α-amanatin of the death cap mushroom inhibits RNA pol II.
What post-translational modification is made to the 5’ end of hnRNA to make it mRNA?
7-methylguanosine 5’ cap
What post-translational modification is made to the 3’ end for mRNA?
poly-A tail
What sequence indicates the site for addition of the poly-A tail?
AAUAAA
What is the Shine-Dalgarno sequence?
It is the site on prokaryotic mRNA that indicates the ribosomal binding site.
What are the two special sequences on the promoter region of eukaryotic DNA at -70 and -25 bases, respectively?
CAAT box and TATA box
What is the size of the eukaryotic ribosome? Each subunit?
80S composed of 60S and 40S
What is the size of the prokaryotic ribosome? Each subunit?
70S = 50S + 30S
What does “polycistronic” refer to?
mRNA transcribed from several genes in a row that can produce several different proteins in a row - only prokaryotic.
