The Student Room Group

What is DNA repair

What is DNA repair
Reply 1
Original post by M1303328
What is DNA repair

DNA repair refers to a collection of processes by which cells identify and correct errors or damage in their DNA molecules. DNA, or deoxyribonucleic acid, is the genetic material that carries the instructions for the development, functioning, and reproduction of all living organisms.

DNA is constantly subjected to various forms of damage, including chemical modifications, breaks, and errors introduced during replication. If left unrepaired, these damages can lead to mutations, genomic instability, and potentially adverse consequences for the cell or organism, such as aging, developmental defects, or increased risk of diseases, including cancer.

DNA repair mechanisms are highly evolved and essential for maintaining the integrity of the genome. Cells possess several intricate repair pathways that act on different types of DNA damage. Here are some of the major DNA repair mechanisms:

Mismatch repair (MMR): Corrects errors that occur during DNA replication, ensuring that the newly synthesized DNA strand matches the original template.

Base excision repair (BER): Deals with small-scale DNA damage, such as modifications or chemical alterations to individual bases. The damaged base is removed and replaced with the correct one.

Nucleotide excision repair (NER): Repairs bulky DNA lesions caused by ultraviolet (UV) radiation or certain chemical compounds. It involves the removal and replacement of a segment of DNA containing the damaged site.

Homologous recombination (HR): Repairs DNA double-strand breaks (DSBs) by using an undamaged sister chromatid or homologous DNA sequence as a template for accurate repair.

Non-homologous end joining (NHEJ): Joins DNA ends resulting from DSBs, often without requiring a homologous template. It is a quick but potentially error-prone repair mechanism.

These are just a few examples of the diverse range of DNA repair pathways. Each mechanism is specialised to detect and correct specific types of DNA damage. The coordination and effectiveness of these repair mechanisms are vital for maintaining genomic stability and preventing the accumulation of mutations that can have detrimental effects on cells and organisms.
Reply 2
Original post by M1303328
What is DNA repair

DNA repair is a cellular mechanism that aims to maintain the integrity and stability of the DNA molecule. DNA can be damaged by various factors, including environmental agents (such as radiation and chemicals) and internal cellular processes (such as errors during DNA replication). Unrepaired or misrepaired DNA damage can lead to mutations and genomic instability, which can have detrimental effects on cellular function and contribute to the development of diseases, including cancer.

DNA repair mechanisms operate at the molecular level and involve complex processes that detect, remove, and repair damaged DNA. There are several major DNA repair pathways, including:

Base Excision Repair (BER): BER repairs DNA damage involving individual damaged bases, such as those caused by oxidation or chemical modifications. It involves the removal of the damaged base by specific enzymes and subsequent replacement with the correct base.

Nucleotide Excision Repair (NER): NER repairs a wide range of DNA lesions, including those caused by UV radiation or certain chemicals. It involves the removal of a segment of damaged DNA containing the lesion and subsequent synthesis of a new DNA strand using the undamaged complementary strand as a template.

Mismatch Repair (MMR): MMR corrects errors that occur during DNA replication, such as the misincorporation of incorrect nucleotides. It recognizes and removes the mismatched base pairs and replaces them with the correct ones.

Homologous Recombination (HR): HR repairs double-strand breaks (DSBs) in DNA, which can occur due to exposure to radiation or other damaging agents. It utilizes a template from a sister chromatid or homologous chromosome to restore the missing or damaged DNA sequence.

Non-Homologous End Joining (NHEJ): NHEJ repairs DSBs in DNA without the need for a homologous template. It directly joins the broken DNA ends, often resulting in small insertions or deletions at the repair site.

These are just a few examples of the many DNA repair mechanisms that exist in cells. The specific repair pathway utilized depends on the type and extent of DNA damage. These repair processes play a crucial role in maintaining genome integrity, preserving genetic information, and ensuring proper cellular function.

Quick Reply