transcription prokaryotes

lesson 4

What are the three steps in the central dogma?

1. dna replication

2. transcription

3. translation

What is mRNA?

dna that is transcribed and taken to ribosomes for AA sequences

what is rRNA?

a component of ribosomes

what is tRNA?

carries AA to ribosome

What is snRNA?

Small nuclear rna that process pre-mRNA to mRNA

What are the three sections of a gene?

promoter RNA coding region and terminator

What enzyme is used in transcription in prokaryotes?

RNA pol

The regulatory sequences (C.M) are recognized by

Sigma unit of RNA pol

Name two C.M that are recognized by sigma factor on RNA pol?

Tataat box (pribnow box) at -10

and TTGACA at -35

Does the promoter determine which strand of DNA is transcribed?

yes

Rna pol combines with sigma factor to form?

rna poly holoenzyme

Does RNA pol need a primer for rna synthesis?

no

What serves as the first nucleotide in the RNA sequence?

Ribonicleoside triphosphate

Wha happens before RNA moves beyond the promoter?

sigma factor is released.

in elongation in transcription in prokaryotes is there a transcription bubble?

yes and it contains dna/rna hybrides

What relieves tension associated with the unwinding of the DNA?

topoisomerase enzymes

What are the two types of termination?

Rho dependent, and Rho independent

The rho factor has similar activity to?

helicase

Where does the rho factor bind to?

the rut site on the rna sequence

What happens when the rho enzyme reaches the terminator?

it unwinds the dna-rna hybrid with helicase activity

For rho independent what is transcribed into rna?

inverted repeats

What does the inverted repeats on the RNA sequence do?

complement each other and therefore form a hairpin structure

What base pairing follows the inverted repeats?

A on template sequence and U on rna sequence

Which base pairing is unstable and causes the RNA molecule to separate from the DNA in rho independent termination?

A w/ U