Bacterial mRNA Life Cycle

Question 1

What is the mRNA life cycle?

Answer 1

Transcription, translation, degradation

Question 2

Why are there multiple ribosomes involved in the bacterial life cycle?

Answer 2

o For transcription: RNA Pol
o Multiple ribosomes for translation
 As RNA Pol moves along the DNA
 As long as it hasn’t hit termination

Question 3

What is the direction of degradation?

Answer 3

from 5’ to 3’ (relative to transcription)

Question 4

What category of enzymes are responsible for mRNA degradation?

Answer 4

• Nucleases: enzymes that degrade nucleic acids (there are ribonucleases and deoxyribonucleases)

Question 5

What are the different types of nucleases?

Answer 5

o Endonucleases: cleave inside, at internal sequences
o Exonucleases: cleave from either end
 5’-to-3’ exonuclease: require 5’-P as template
 3’-to5’ exonuclease requires 3’-OH

Question 6

What are the steps of mRNA degradation?

Answer 6

o Endonucleases cut RNA in pieces (generationg 3’-OH ends)

o Exonucleases cut nucleotides