Midterm Flashcards
What is the difference between constitutive and non-inducible genes?
Constitutive are always produces- like house keeping proteins
Inducible proteins are only produced under certain environmental conditions
Define the difference between these:
activator
enhancers
Inducer
activator is the same as regulatory protein - CAP protein
enhancers are not proteins - sequence- CAP binding site
inducer- lactose , arabinose, tyrp, metal ions and
What does RNA poly I, II, III transcribe?
RNA poly I- rRNA
RNAP II- mRNA, snoRNA, miRNA (some snRNA)
RNAPIII- tRNA, 5sRNA (some snRNA)
How many subunits are there in RNAP II?
12
Which RNA poly have CTD tail?
ONLY in rbpI of RNAP II
What is α-amanitin and what is most sensitive to it?
A small lipid soluble molecule that DOES NOT bind to DNA or the active site of RNAP II - it stops translocation after the first phosphodiester bond is produced.. RNAPII is the most sensitive to the chemical
What is unique about the consensus repeat of CTD tail ?
The amino acids in the consensus repeats contain have -OH, so this is a hydrophilic and phosphorylatable site
Is the unphosphorylated or phosphorylated CTD tail used for initiation of transcription?
Unphosphosphorylated tale- but In the areas of high level of transcription only phosphorylated CTD is present
What is the function of rbp 1 and rbp 2?
rbp I contains the CDT tail, DNA binding site, responsible for α-amanitin sensitivity
rbp II - polymerization – contains active site THAT includes single Mg 2+ and conserved aspartate motif – RNA synthesis
True/False: Both Eukaryotes and Prokaryotes have operons?
False- so far no operons have been found associated in Eukaryotes and Each eukaryotic gene has specific control sequences (protein binding sites) – gene transcriptions are controlled individually
What is the major point of transcription control in both eu and pro?
Transcription initiation
What is the major pitfall with northern blot. in situ hybridization, microarrays ? And the main difference between these methods and run-off, run-on, and reporter gene?
They measure the steady state transcript level but this can not distinguish between the degradation rate and transcription rate - measure only mRNA abundance at the end .
Gives the rate of transcription- insight into how efficient it is because mRNA is getting transcribed during the assay
True/False: Increase in transcription rate always leads to the increase in mRNA and hence protein level in the cell?
False- in most cases it is true but not in all
