Porkaryotic Gene Regulation

Week 15: Monday, December 1st: Prokaryotic Gene Regulation; Eukaryote Gene Regulation Preview

_______ is used as lncRNA to affect gene expression by:

1. activating DNA methyltransferase (DNMT) to methylate cytosine on DNA

2. activating histone methyltransferase (HMT) to methylate K and R on histone tails

3. complementing RNA and chopping it

4. blocking mRNA from entering the ribosome

asRNA (antisense)

how many termination signals for are needed for polycistronic transcripts?

one

how many shine delgarno sequences are needed for polycistronic transcripts and why?

one for each gene so the ribosome doesnt dissociate after each stop codon

are prokaryotic genes always on or off?

always off

operons need PROG, which stands for:

promoter, regulatory gene/repressor, operator, linked structural genes

operons are expressed by _______, which are acitvated by _______

activators, inducers

positive control of operons is when the gene is _______, but when the regualtory protein binds, its turned _______ (like cAMP and CAP)

off, on

opersons are inhibited by _______, which needs _______ to bind force to enforce this

repressors, co-repressors

negative control of operons is when the gene is _______, but when the regulatory protein binds, its turned _______ (like lac and trp operons)

on, off

is the lac operon induced or reduced by lactose, and why?

induced because if there’s no lactose the operon is off, but if there is lactose the operon is on

when glucose is high, _______ is low and CAP can’t bind so the operon runs weakly

cAMP

is the trp operon induced or repressed by tryptophan, and why?

repressed because of there’s no tryptophan the operon is on, but if there is tryptophan the operon is off

_______ is when tryptophan and its tRNA is high, causing the ribosome to move fast and the mRNA to fold in to the termination loop

attenuation

mRNA will form the _______ to prevent early termination when tryptophan and its tRNA is low, causing the ribosome to move slow

anti-terminator loop