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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Multiple Choice

In the context of DNA repair, proofreading by DNA polymerases includes which of the following tasks?

Recognition and excision of thymine dimers caused by UV light

Repair of double-strand breaks via homologous recombination

Removal of incorrectly incorporated nucleotides during DNA synthesis

Addition of methyl groups to cytosine bases

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Verified step by step guidance

Understand the role of DNA polymerase proofreading during DNA replication, which primarily involves ensuring the accuracy of DNA synthesis.

Recall that DNA polymerases have a 3' to 5' exonuclease activity that allows them to remove incorrectly incorporated nucleotides immediately after they are added.

Recognize that proofreading does not involve repair of thymine dimers (which are fixed by nucleotide excision repair) or double-strand breaks (which are repaired by homologous recombination or non-homologous end joining).

Note that addition of methyl groups to cytosine bases is a form of DNA methylation, a separate epigenetic modification process, not related to proofreading.

Conclude that the key task of proofreading by DNA polymerases is the removal of incorrectly incorporated nucleotides during DNA synthesis to maintain replication fidelity.