Concept explainers
Attenuation affects anabolic pathways, whereas repression affects either anabolic or catabolic pathways. Provide an explanation for this.
The bacterial cells can also regulate the process of transcription termination in addition to regulating the transcription initiation. In such type of regulation, the transcription is initiated but stopped prematurely depending on the needs of the organisms and their environmental conditions. Attenuation is an example of this kind of regulation. Repression refers to the “turning off” of genes with the help of a repressor factor. This factor prevents the binding of RNA polymerase to its promoter region or prevents it from reading the downstream DNA thereby prevents the mRNA synthesis.
Explanation of Solution
Attenuation is a kind of regulatory mechanism. It involves the interaction between the transcriptional and translational machinery. This interaction specifically occurs in RNA polymerase and ribosomes. In the cell, this mechanism senses the specific amino acid levels or other metabolites. Thus, it is found to be limited in regulating anabolic operons for the biosynthesis of amino acids and other metabolites.
In order to govern the transcription process, the repressor proteins are used in repression. It can be used either to allow the transcription in the presence of an inducer or to block the transcription in the presence of co-repressor. It is found to be a more flexible and general process of gene regulation. Thus, it affects both anabolic and catabolic pathways.
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Chapter 14 Solutions
PRESCOTTS GENERAL MICROBIOLOGY
- Explain why inactivation of the O1 sequence of the lac operator almost completely abolishes repression of the lac operon.arrow_forwardCan you explain in technical detail how global control mechanisms of catabolite repression work? Thank Youarrow_forwardWhat is known as catabolite repression ?arrow_forward
- Discuss genetic evidence that lacI encodes an allostericrepressor protein that binds the operator DNA.arrow_forwardDescribe the mechanism by which cAMP receptorprotein (CRP), the regulatory protein for catabolite repression, functions. Use the lactose operon as an example.arrow_forwardRepressors are inactivated either by interaction with a small-molecule inducer or by proteolytic cleavage. Why is it advantageous for a repressor like the lac repressor to be inactivated by binding to allolactose rather than by proteolytic cleavage?arrow_forward
- When cAMP binds to the Catabolite Activator Protein (CAP), it causes a conformational change on the protein, which results in binding to the CAP-binding site on the DNA and ___________________________ of the lac operon. This conformational change induced by the binding of another molecule is known as a(n) _________________________________. transcription repression; binding effect translation; distortion effect mutation; interactive effect attenuation; compression effect transcription activation; allosteric effectarrow_forwardExplain the role/importance of the localization of GTPase-activating protein (Ran-GAP) in BOTH nuclear export and import. What would occur if there was a loss of function mutation in Ran-GAP? What would occur if Ran-GAP was localized in the nucleus?arrow_forwardThe TRP operon functions by attenuation. Briefly explain how attenuation works and why it is necessary, in addition to the repressor protein, in regulating the operon.arrow_forward
- If the binding activity was purified, suggest two experimental approaches that could be taken to verify that this factor is in fact a transcription factor? Explain.arrow_forwardThe concentration of DnaK increases after a heat shock, yet its effects on sigma-32 activity are very negative. How could the increase in a protein that inhibits the activity of sigma-32 lead to an increase in the transcription of heat shock proteins?arrow_forwardCTP synthetase is allosterically activated by GTP. What function might this play in the cell?arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning