Attenuation Flashcards
1
Q
What is Attenuation?
A
A process that plays a role in regulating the formation of enzymes involved in amino acid biosynthesis by transcription termination
2
Q
How are Stem & Loop structures formed?
A
By transcribing the DNA sequence encoding the leader peptide into RNA
3
Q
Where can attenuation occur and why?
A
Only in prokaryotes because transcription and translation are linked
4
Q
What happens when excess Tryptophan is available to the cell?
A
- Cell wants Trp operon OFF to save energy
- Abundance of tryptophanyl tRNA allows tryptophan-rich leader peptide to be made
- Stem & loop forms in the produced mRNA which functions as a transcriptional termination signal
5
Q
What happens when Tryptophan is scarce in the cell?
A
- Cell wants Trp operon ON
- Shortage of tryptophanyl tRNA forces ribosome to halt translation at Trp codons in the mRNA encompassing the leader sequence
- Prevents formation of terminator stem & loop and allows RNA polymerase to continue transcription of Trp operon
6
Q
What is Tryptophan biosynthesis subject to?
A
- Gene repression
- Attenuation
- Feedback Inhibition
7
Q
Which regulatory processes in Tryptophan biosynthesis are at Gene Expression level?
A
- Gene Repression
- Attenuation
8
Q
Which regulatory process in Tryptophan biosynthesis is a Post Translational Control System?
A
Feedback Inhibition
