DNA can repair itself

Deoxyribonucleic acid, as its name implies, carries genetic information. It carries information about our eye color, body shape, and even information about proper diet and birth defects. Deoxyribonucleic acids encode all the proteins in our bodies. And proteins represent functions such as hormones, antibodies, and structural units like hair and nails. [And they are responsible for the musculoskeletal system, with actin and myosin fibers folding into more complex structures and eventually transforming into muscle. Once a protein is formed, it must first be transcribed into RNA, which can leave the nucleus of a eukaryotic cell and thus risk degradation. Translation (translocation) of the genetic information then takes place. Cells undergo some form of repeated division, and this is how cell growth and reproduction occur. In this division, however, DNA must be evenly distributed. Therefore, DNA is replicated by a complex mechanism. DNA polymerase can make mistakes. This mistake is called a mutation. However, DNA is the only molecule with a complex self-repair mechanism built in.
pyrimidinový nukleotid
The most common damages are due to:
– UV and X-irradiation
– Chemical actions, mainly alkylating agents
– Reactive oxygen species (i.e. oxidative stress)
Repaired in several ways:
1. Direct repair: Upon UV exposure, pyrimidine dimers are formed. Thus, the two thymine residues present on the DNA begin to form covalent bonds. Repair is performed by the enzyme CPD photolyase, which simply removes this covalent bond.
2. Cleavage type: Here, chain complementarity is exploited. Only nitrogen bases, entire nucleotides, or specific portions of the sequence where the defective pair is present can be cut. The old strand, unlike the new strand, has a methyl tag, which is recognized by it.
3. Use of sister chromatids: A chromosome is composed of two identical chromosomal segments. One damaged one can use the other as a template. In the worst case, all the defective information is discarded. However, it can also kill the cell.
vlákno DNA
In other words, cancer is a disease in which mutations occur and cells overgrow (even become unstoppable).