RNA synthesis and regulation in BACTERIA

What is transcription?

Creation of RNA from DNA

What does RNA polymerase require to make a transcript?

Template, NTPs, metal ion (Mg2+, etc)

Does RNA polymerase require a primer?

No

Which strand of the DNA has the same sequence as the transcript (except for U instead of T in the RNA)?

The coding strand (NOT THE TEMPLATE)

What are the differences between RNA and DNA synthesis?

RNA synthesis doesn’t need a primer, uses NTPs, and uses U instead of T

DNA synthesis needs a primer, uses dNTPs, and uses T instead of U

What are the three types of RNA?

mRNA - encodes information needed to make a protein

tRNA - transfers amino acids during translation

rRNA - ribosomal RNA

What is the purpose of the sigma subunit?

Recognizes promoter sites, detaches from the transcription holoenzyme, allowing transcription to begin

How does RNA polymerase know where to start transcription?

Promoter sequences on DNA direct polymerase to transcription start site

What happens when RNA polymerase recognizes a promoter site?

It interacts with the -10 and -30 elements

What are the two different mechanisms of transcription termination?

Intrinsic/protein-independent termination through stem-loop structures

Rho/protein-dependent termination - rho uses ATP to stop transcription

What is lac I in the lac operon?

Repressor

What is lacZ in the lac operon?

Beta-galactosidase

What binds to the repressor in the lac operon and allows transcription to proceed?

Allolactose

What does the lac repressor bind to?

the operator

When glucose levels are low, cAMP levels are _______

high

What does cAMP in the lac operon do?

cAMP increases lac gene transcription