Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

17. Mutation, Repair, and Recombination

DNA Repair

Genetics

17. Mutation, Repair, and Recombination

DNA Repair

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1:49 minutes

Problem 13b

Textbook Question

Answer the following questions concerning the accuracy of DNA polymerase during replication.
If a DNA replication error is detected by DNA polymerase, how is it corrected?

Verified step by step guidance

DNA polymerase has a proofreading function that helps maintain the accuracy of DNA replication. This function is carried out by its 3' to 5' exonuclease activity.

When DNA polymerase incorporates an incorrect nucleotide during replication, the enzyme detects the mismatch due to improper base pairing.

The 3' to 5' exonuclease activity of DNA polymerase removes the incorrectly paired nucleotide from the newly synthesized strand.

After the incorrect nucleotide is removed, DNA polymerase resumes synthesis by adding the correct nucleotide to the growing strand.

This proofreading mechanism significantly reduces the error rate during DNA replication, ensuring high fidelity in the process.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

DNA Polymerase Function

DNA polymerase is an enzyme responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand during replication. It plays a crucial role in ensuring the accuracy of DNA replication by proofreading the newly synthesized DNA.

Proofreading Mechanism

DNA polymerase has a built-in proofreading ability that allows it to detect and correct errors in the DNA sequence. When an incorrect nucleotide is incorporated, the enzyme can reverse its activity, excise the erroneous nucleotide, and replace it with the correct one, thus maintaining fidelity during DNA replication.

Mismatch Repair System

In addition to the proofreading function of DNA polymerase, cells have a mismatch repair system that identifies and repairs any remaining errors after replication. This system involves several proteins that recognize mismatched base pairs, excise the incorrect segment, and fill in the gap with the correct nucleotides, further enhancing the accuracy of DNA replication.

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Related Practice

Multiple Choice

True or False:Translesion DNA synthesis is the first mechanism the cell uses to repair DNA damage?

Which of the following pathways is an error-free way to repair double-stranded breaks?

Write a short essay contrasting how these concepts may differ between bacteria and eukaryotes.

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Textbook Question