DNA Repair

Definition

DNA repair is the process by which cells identify and correct various types of damage to the DNA molecules that encode their genetic information. This process is essential for maintaining the integrity and proper function of the genome, as unrepaired DNA damage can lead to mutations and genomic instability.

5 Must Know Facts For Your Next Test

1. DNA repair mechanisms are crucial for preventing the accumulation of mutations that can lead to diseases such as cancer.
2. Different DNA repair pathways target specific types of DNA damage, including single-strand breaks, double-strand breaks, and base modifications.
3. The efficiency of DNA repair processes declines with age, contributing to the increased risk of genetic disorders and cancer in older individuals.
4. Defects in DNA repair genes can lead to rare genetic disorders, such as xeroderma pigmentosum and Werner syndrome, which are characterized by increased sensitivity to DNA-damaging agents and premature aging.
5. DNA repair mechanisms are closely linked to the cell cycle, as DNA damage can trigger cell cycle checkpoints and influence decisions about cell fate, such as cell cycle arrest, DNA repair, or apoptosis.

Review Questions

• Explain the role of DNA repair in maintaining genomic integrity and preventing mutations.
  • DNA repair mechanisms are essential for maintaining the stability and proper function of the genome. By identifying and correcting various types of DNA damage, such as single-strand breaks, double-strand breaks, and base modifications, DNA repair processes help prevent the accumulation of mutations that can lead to genetic disorders, including cancer. Efficient DNA repair is crucial for ensuring the accurate transmission of genetic information during cell division and for preserving the overall health and viability of cells.
• Describe the different DNA repair pathways and the types of DNA damage they target.
  • There are several distinct DNA repair pathways, each specialized in addressing specific types of DNA damage. Nucleotide excision repair removes and replaces DNA segments containing damaged nucleotides, such as those caused by UV radiation or certain chemicals. Base excision repair corrects single damaged or inappropriate DNA bases, like those resulting from oxidation, alkylation, or deamination. Mismatch repair, on the other hand, targets errors made during DNA replication, where an incorrect nucleotide is paired with the correct one. The existence of these specialized repair mechanisms ensures that cells can effectively respond to a wide range of DNA lesions and maintain genomic stability.
• Analyze the relationship between DNA repair, cell cycle regulation, and cellular decision-making.
  • DNA repair processes are closely integrated with cell cycle regulation and cellular decision-making. When DNA damage is detected, it can trigger cell cycle checkpoints that pause the cell cycle, allowing time for DNA repair to occur. The efficiency of DNA repair, in turn, influences the cell's decision-making process, which may involve cell cycle arrest, DNA repair, or, if the damage is too severe, apoptosis (programmed cell death). This interplay between DNA repair and cell cycle regulation is crucial for preserving genomic integrity and preventing the propagation of cells with unrepaired DNA damage, which could lead to the accumulation of mutations and the development of diseases like cancer.

Related terms

Nucleotide Excision Repair: A DNA repair mechanism that removes and replaces DNA segments containing damaged nucleotides, such as those caused by UV radiation or certain chemicals.

Base Excision Repair: A DNA repair pathway that removes and replaces single damaged or inappropriate DNA bases, such as those resulting from oxidation, alkylation, or deamination.

Mismatch Repair: A DNA repair process that corrects errors made during DNA replication, where an incorrect nucleotide is paired with the correct one, leading to a mismatch.