regulation of microbial gene expression

Question 1

difference between eukaryotic and prokaryotic transcription

Answer 1

prokaryotic = genes lack introns. transcription and translation are coupled and both occur in the cytoplasm
eukaryotic= introns mostly code for a single protein. transcription occurs in nucleas and translation occurs in cytoplasm.

Question 2

gene expression in prokaryotes?
-RNA polymerase
-promotor
-sigma factor

Answer 2

1) RNA polymerase binds to promotor
2) sigma factor binds to RNA polymerase and guides it to promotor
3) following transcription initiation, sigma factor will dissociate and trasncription will continue to move along and grow

Question 3

what does it mean by polycistronic?

Answer 3

more than one gene is transcribed at onece on a single mRNA

Question 4

ecoli genome structure

Answer 4

concists of housekeeping genes expressed at a constent level

Question 5

what is lactose brocken down into by lactose (lac) operon

Answer 5

-glucose
-galactose

Question 6

repression negative control mechanism in e.coli lac operon
-if lactose is present
-if glucose is present

Answer 6

lactose is present= e.coli lac operon is expressed which allows transcription

glucose is present= e.coli lac operon is not expressed, which dosen’t allow transcription

Question 7

activation positive control mechanism in e.coli lac operon
-when glucose is low
-cAMP
-CAP

Answer 7

when glucose is low.
cAMP is produced, which binds to CAP, then initates RNA polymerase transcriptional start
CAP controls many operons

Question 8

the tryptophan (trp) operon in e.coli is involved in the syntehsis of tryptophan.
when is the operon repressed?

Answer 8

the trp operon is repressed when trytophan levels are high
-low trp= high levels of operon

Question 9

what does uropathogenic e.coli cause?

Answer 9

urinary tract and bloodstream infections

Question 10

what does transcriptonomics do?
what is transcriptome?

Answer 10

1) monitors gene expression differences
2) all RNA molecules in a cell or a population of cells

Question 11

african trypanosomes subspecies
1) T.b gambiense
2) T.b rhodesiense
3) T.b brucei

Answer 11

1) causes a chronic disease that can take years to develop- 98% of cases
2) causes an acute disease that can be fatal in a matter of months if not treated- 2% of cases
3) cannot survive in human serum due to Apol-1 killing parasite therefore does not infect humans.