RNA Synthesis

Question 1

how is RNA in prokaryotes unique?

Answer 1

• in prokaryotes, 1 piece of RNA can encode for multiple products
• this is contrary to eukaryotes

Question 2

what is a gene?

Answer 2

best definition: DNA sequence that encodes for a functional product

Question 3

RNA structure

Answer 3

• single stranded
• unstable

Question 4

what is the mRNA leader sequence?

Answer 4

• conserved sequence at the 5’ end of mRNA
• contains the shine-delgarno sequence ‘AGGA’
• this tells the ribosome where to start translating
• this is in prokaryotes only!!
• when ribosome sees shine-delgarno, it will start translating at the next AUG

Question 5

what is the mRNA trailer sequence?

Answer 5

• palindromic: reads the same forward as backward
• causes the new mRNA to form a hairpin loop
• physical folding of the hairpin loop will stop transcription
• also prokaryotes only

Question 6

describe mRNA synthesis (DNA transcription) in prokaryotes

Answer 6

• have only one RNA polymerase
• RNA poly binds to a promoter region
• either strand can be the template
• RNA poly sees recognition site: -35
• then, it counts to RNA pol binding site: -10 (TATTA box)
• then it counts until +1 and starts transcribing