DNA repair

Definition

DNA repair refers to the collection of processes by which a cell identifies and corrects damage to its DNA molecules that encode its genome. This is crucial for maintaining genomic stability and preventing mutations that can lead to cancer and other diseases. Effective DNA repair mechanisms are essential for the proper functioning of the cell cycle, as they ensure that damaged DNA does not lead to errors during cell division.

5 Must Know Facts For Your Next Test

1. DNA repair systems can be broadly categorized into direct reversal, excision repair, and double-strand break repair mechanisms.
2. The p53 protein plays a significant role in DNA repair by detecting DNA damage and initiating repair processes or triggering apoptosis if the damage is irreparable.
3. Defects in DNA repair pathways can lead to increased susceptibility to cancer due to the accumulation of mutations.
4. There are specialized DNA repair proteins, such as BRCA1 and BRCA2, that are crucial for repairing double-strand breaks and are linked to breast and ovarian cancer when mutated.
5. Certain external factors like UV light or chemical exposure can cause specific types of DNA damage that are recognized and repaired by specialized repair pathways.

Review Questions

• How do DNA repair mechanisms prevent the onset of cancer during the cell cycle?
  • DNA repair mechanisms are essential for maintaining genomic integrity, particularly during the cell cycle when DNA is replicated. By identifying and fixing errors or damage before a cell divides, these mechanisms reduce the likelihood of mutations being passed on to daughter cells. If DNA damage is left uncorrected, it can lead to uncontrolled cell growth and contribute to cancer development.
• What role does the p53 protein play in coordinating DNA repair and the cell cycle?
  • The p53 protein acts as a critical checkpoint regulator in the cell cycle by sensing DNA damage. Upon detecting such damage, p53 can halt the cell cycle, allowing time for repair processes to occur. If the damage is too severe, p53 can initiate apoptosis to prevent the propagation of potentially cancerous cells. This mechanism underscores the link between DNA repair and proper cell cycle regulation.
• Evaluate how defects in DNA repair pathways might influence cancer treatment strategies.
  • Defects in DNA repair pathways can significantly impact cancer treatment strategies by influencing how tumors respond to therapies like radiation and chemotherapy, which induce DNA damage. Tumors with compromised repair mechanisms may be more susceptible to these treatments because they cannot effectively fix the induced damage. This understanding has led to targeted therapies that exploit these weaknesses in cancer cells, paving the way for personalized medicine approaches in oncology.

Related terms

Mutagenesis: The process by which genetic information is changed, resulting in mutations, often due to environmental factors like radiation or chemicals.

Apoptosis: The process of programmed cell death that eliminates damaged or potentially dangerous cells, helping prevent the propagation of mutations.

Cell Cycle Checkpoints: Control mechanisms in the cell cycle that ensure proper division and prevent the progression of cells with damaged DNA.