Examples of operon in the following topics:
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- The lac operon is an inducible operon that utilizes lactose as an energy source and is activated when glucose is low and lactose is present.
- A major type of gene regulation that occurs in prokaryotic cells utilizes and occurs through inducible operons.
- The lac operon is a typical inducible operon.
- However, for the lac operon to be activated, two conditions must be met.
- Describe the components of the lac operon and their role in its function
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- The trp operon is a repressor operon that is either activated or repressed based on the levels of tryptophan in the environment.
- These five genes are next to each other in what is called the tryptophan (trp) operon .
- The five coding regions for the tryptophan biosynthesis enzymes are arranged sequentially on the chromosome in the operon.
- The five genes that are needed to synthesize tryptophan in E. coli are located next to each other in the trp operon.
- Explain the relationship between structure and function of an operon and the ways in which repressors regulate gene expression
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- When glucose levels decline in E. coli, catabolite activator protein (CAP) is bound by cAMP to promote transcription of the lac operon.
- This type of process can be seen in the lac operon which is turned on in the presence of lactose and absence of glucose.
- When glucose levels decline in the cell, accumulating cAMP binds to the positive regulator catabolite activator protein (CAP), a protein that binds to the promoters of operons that control the processing of alternative sugars, such as the lac operon.
- In these operons, a CAP-binding site is located upstream of the RNA-polymerase-binding site in the promoter.
- As cAMP-CAP is required for transcription of the lac operon, this requirement reflects the greater simplicity with which glucose may be metabolized in comparison to lactose.