Podcast
Questions and Answers
What is the primary function of the SOS response system in E. coli?
Which two genes are primarily involved in governing the expression of the SOS response?
What role does the RecA protein play in the SOS response?
How does the LexA repressor maintain the SOS response genes in an 'off' state?
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What consequence does the relaxation of polymerase III's proofreading function have during the SOS response?
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In the context of the SOS response, what might be a potential benefit of enhanced mutagenesis?
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Which of the following genes is involved in excision repair as part of the SOS response?
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What initiates the activation of the SOS response system?
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What effect does the binding of RecA protein to single-stranded DNA have on its own structure?
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What is the primary role of the LexA protein in uninduced cells?
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Which event leads to the activation of the SOS response?
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What happens to the levels of LexA after the repair of DNA damage is completed?
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What is the function of the activated RecA* protein in the context of the SOS response?
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How does the SOS response affect the activity of pol III?
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What is the result of the RecA protein returning to its inactive form after completing DNA repair?
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Which outcome is associated with the self-cleavage of LexA protein?
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Study Notes
The SOS Response
- The SOS Response is activated in response to DNA damage.
- The SOS response is characterized by the RecA and LexA proteins.
- RecA inhibits editing function of DNA polymerase III.
- RecA binds to damaged DNA and prevents polymerase III from being stalled.
- RecA converts to RecA* which stimulates LexA to inactivate itself.
- LexA is a repressor protein and inhibits expression of several genes when present.
- The SOS response leads to error-prone DNA repair.
- LexA represses the expression of itself, leading to normal DNA repair.
- The SOS response allows E.coli to survive damaging conditions.
- The SOS response is a last-ditch survival mechanism.
- LexA is a repressor protein and prevents gene expression under normal conditions.
The SOS Response - Figure 10-9
- LexA represses the expression of genes involved in SOS response under normal conditions.
- DNA damage activates RecA to RecA*.
- RecA* inactivates LexA, leading to expression of genes involved in SOS response.
- Expression of SOS response genes facilitates repair of DNA damage.
- The SOS response ends when RecA returns to RecA.
- LexA is no longer inactivated and represses the expression of SOS genes.
- Error prone repair is induced throughout this process.
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Description
Explore the SOS response mechanism activated in bacteria like E. coli when DNA damage occurs. This quiz delves into the roles of key proteins such as RecA and LexA in regulating DNA repair processes. Test your understanding of this crucial survival response.
