Excision Repair

Definition

Excision repair is a DNA repair mechanism that removes and replaces damaged or incorrect DNA bases to maintain the integrity of the genetic code. It is a crucial process that helps prevent the accumulation of mutations that could lead to various genetic disorders and diseases.

5 Must Know Facts For Your Next Test

1. Excision repair is a highly conserved process found in all domains of life, from bacteria to humans, highlighting its importance in maintaining genomic stability.
2. The excision repair process involves the recognition of DNA damage, incision of the damaged DNA, removal of the damaged segment, and synthesis of a new, undamaged DNA sequence to replace the excised region.
3. Deficiencies in excision repair pathways have been linked to various genetic disorders, such as xeroderma pigmentosum, which increases the risk of skin cancer due to an inability to repair UV-induced DNA damage.
4. The efficiency of excision repair can be influenced by factors such as age, environmental exposures, and genetic variations, which can contribute to the accumulation of mutations and the development of disease.
5. Excision repair mechanisms play a crucial role in preventing the development of cancer by removing DNA lesions that could lead to the activation of oncogenes or the inactivation of tumor suppressor genes.

Review Questions

• Describe the general process of excision repair and explain how it helps maintain genomic integrity.
  • Excision repair is a DNA repair mechanism that removes and replaces damaged or incorrect DNA bases to preserve the integrity of the genetic code. The process involves the recognition of DNA damage, incision of the damaged DNA, removal of the damaged segment, and synthesis of a new, undamaged DNA sequence to replace the excised region. This repair process is essential for preventing the accumulation of mutations that could lead to genetic disorders and diseases, such as cancer. By removing and replacing damaged DNA, excision repair helps maintain the fidelity of the genetic information and ensures the accurate transmission of genetic material to future generations.
• Explain the differences between nucleotide excision repair and base excision repair, and discuss their respective roles in maintaining genomic stability.
  • Nucleotide excision repair and base excision repair are two distinct types of excision repair mechanisms. Nucleotide excision repair removes and replaces DNA segments containing bulky, helix-distorting lesions, such as those caused by ultraviolet radiation or certain chemical agents. In contrast, base excision repair removes and replaces single, chemically modified DNA bases, such as those resulting from oxidative damage or alkylation. While the specific types of DNA damage they target differ, both nucleotide excision repair and base excision repair play crucial roles in maintaining genomic stability. By removing and replacing damaged DNA, these repair mechanisms help prevent the accumulation of mutations that could lead to genetic disorders and diseases, including cancer. The efficient functioning of these excision repair pathways is essential for the overall health and well-being of an organism.
• Analyze the potential consequences of deficiencies in excision repair pathways and discuss how they can contribute to the development of genetic disorders and diseases.
  • Deficiencies in excision repair pathways can have significant consequences for an organism's health and well-being. For example, a deficiency in the nucleotide excision repair pathway has been linked to the genetic disorder xeroderma pigmentosum, which increases the risk of skin cancer due to an inability to repair UV-induced DNA damage. Similarly, deficiencies in other excision repair mechanisms can lead to the accumulation of various types of DNA lesions, which can ultimately result in the activation of oncogenes or the inactivation of tumor suppressor genes, contributing to the development of cancer. The efficiency of excision repair can be influenced by factors such as age, environmental exposures, and genetic variations, all of which can impact an individual's susceptibility to genetic disorders and diseases. By understanding the critical role of excision repair in maintaining genomic integrity, researchers and clinicians can develop targeted interventions and therapies to address deficiencies in these repair pathways and mitigate the associated health risks.

Related terms

Nucleotide Excision Repair: A type of excision repair that removes and replaces DNA segments containing bulky, helix-distorting lesions, such as those caused by ultraviolet radiation or certain chemical agents.

Base Excision Repair: A type of excision repair that removes and replaces single, chemically modified DNA bases, such as those resulting from oxidative damage or alkylation.

Mismatch Repair: A DNA repair mechanism that corrects base-pairing mistakes that occur during DNA replication, ensuring the accurate transmission of genetic information.