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

What is the most likely consequence if DNA ligase is mutated and loses its function during DNA repair?

Nicks in the DNA backbone will remain unsealed, leading to strand breaks.

DNA polymerase will be unable to synthesize new DNA strands.

Mismatch repair proteins will fail to recognize errors.

Excision of damaged bases will not occur.

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Verified step by step guidance

Understand the role of DNA ligase in DNA repair: DNA ligase is an enzyme responsible for sealing nicks or breaks in the sugar-phosphate backbone of DNA, effectively joining Okazaki fragments during replication and sealing repaired DNA strands.

Identify what happens during DNA repair processes: After damaged bases are excised and new nucleotides are inserted by DNA polymerase, DNA ligase seals the remaining nicks to restore the integrity of the DNA strand.

Analyze the consequence of a non-functional DNA ligase: If DNA ligase loses its function, the nicks in the DNA backbone created during repair or replication will remain unsealed.

Consider the impact of unsealed nicks: Persistent nicks can lead to strand breaks, which compromise the stability and continuity of the DNA molecule, potentially causing mutations or cell death.

Differentiate this from other repair steps: DNA polymerase synthesizes new DNA but does not seal nicks; mismatch repair proteins recognize errors but do not seal nicks; excision removes damaged bases but sealing is done by ligase.