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Questions and Answers
Which of the following is true about the lac operon?
What is the role of lacZ in the lac operon?
Where is the operator located in the lac operon?
What is the main function of the lac operon?
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Which bacteria is the lac operon found in?
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What is the function of the lac repressor protein in the absence of lactose?
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Which molecule acts as an inducer in the lac operon?
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What is the main function of the trp operon?
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Which component of the trp operon acts as a regulatory region where a repressor protein can bind to control gene expression?
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What happens to the trp repressor protein in the presence of tryptophan?
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Study Notes
- The lac operon and trp operon are two significant operons in bacteria, located in E. coli.
- The lac operon manages lactose metabolism, whereas the trp operon oversees tryptophan biosynthesis.
- The lac operon includes the structural genes lacZ, lacY, and lacA, which encode proteins involved in lactose metabolism, a promoter, and an operator.
- lacZ encodes β-galactosidase
- lacY encodes lactose permease
- lacA encodes transacetylase
- Regulation of the lac operon occurs via the presence or absence of lactose and glucose.
- Lac repressor binds to the operator when lactose is absent, preventing transcription.
- Allolactose, derived from lactose, serves as an inducer, changing the lac repressor's conformation and releasing it from the operator to enable transcription.
- The trp operon consists of the structural genes trpE, trpD, trpC, trpB, and trpA, a promoter, an operator, and regulates tryptophan biosynthesis.
- Regulation of the trp operon hinges on the availability of tryptophan.
- Trp repressor is inactive without tryptophan, allowing transcription.
- Tryptophan acts as a corepressor when present, binding to the trp repressor and altering its conformation, preventing transcription.
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Description
Learn about the lac operon and trp operon, two essential operons in E. coli bacteria. Understand the functions of the structural genes, the regulatory mechanisms, and the role of inducers and corepressors in gene expression.
