10 Questions
During DNA replication, DNA polymerases have high fidelity because
The active site of the polymerase domain selects the correct nucleotide opposite the template
Which DNA polymerase activity is responsible for removing RNA primers during DNA replication?
5'->3' exonuclease activity
Which DNA polymerase(s) have exonuclease proofreading activity?
DNA pol I and III
What is the error rate of DNA polymerase exonuclease proofreading?
10^-6 to 10^-7
What is the purpose of DNA mismatch repair?
To correct errors missed by DNA polymerase proofreading
What is the role of DNA polymerases during replication?
DNA polymerases incorporate correct nucleotides opposite the template strand.
How does DNA polymerase ensure high fidelity during replication?
The active site of the polymerase domain selects the correct nucleotide, and if a wrong nucleotide is selected, it is recognized and removed by the exonuclease domain through proofreading.
What is the error rate of DNA polymerase exonuclease proofreading?
The error rate of DNA polymerase exonuclease proofreading is $10^{-6}-10^{-7}$.
What is the purpose of DNA mismatch repair?
The purpose of DNA mismatch repair is to correct errors that escape DNA polymerase proofreading, reducing the error rate to $10^{-9}-10^{-11}$.
What can mutations result in?
Mutations can result in disorders or allelic variety in evolution.
Study Notes
DNA Replication and Fidelity
- High fidelity of DNA polymerases during DNA replication is due to their ability to proofread and edit newly synthesized DNA strands.
- The DNA polymerase activity responsible for removing RNA primers during DNA replication is DnaB helicase.
- DNA polymerases with exonuclease proofreading activity include DNA polymerase I and DNA polymerase III.
- The error rate of DNA polymerase exonuclease proofreading is 10^(-6) to 10^(-8) errors per nucleotide.
- The purpose of DNA mismatch repair is to correct mismatches that occur during DNA replication, ensuring genome stability.
- The role of DNA polymerases during replication is to synthesize new DNA strands by adding nucleotides to a primer sequence.
- DNA polymerase ensures high fidelity during replication by using a proofreading mechanism to correct errors in real-time, and an exonuclease activity to remove incorrectly incorporated nucleotides.
- Mutations can result in changes to the genetic code, leading to altered protein function or expression, and potentially causing disease.
Test your knowledge on DNA polymerases and their role in DNA replication, mutation, and repair. Learn about the mechanisms that allow DNA polymerases to maintain high fidelity during replication and how they correct mistakes. Explore the selectivity of DNA polymerase active sites and the proofreading capabilities of exonuclease domains.
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