DNA strand breaks have significant impacts on cell functions, as they can lead to mutations, genomic instability, and cell death if not repaired properly. DNA, or deoxyribonucleic acid, is the genetic material that encodes the information necessary for the proper functioning and reproduction of cells. It is composed of nucleic acids, which are the building blocks of DNA.There are two types of DNA strand breaks: single-strand breaks SSBs and double-strand breaks DSBs . SSBs occur when one of the two DNA strands is broken, while DSBs involve breaks in both strands. DSBs are more severe and can lead to chromosomal rearrangements, deletions, or translocations, which can result in cancer or other genetic diseases.Nucleic acids play a crucial role in DNA repair mechanisms. There are several repair pathways that cells use to fix DNA strand breaks, including base excision repair BER , nucleotide excision repair NER , mismatch repair MMR , homologous recombination HR , and non-homologous end joining NHEJ . These pathways involve various enzymes and proteins that recognize and repair damaged DNA, ensuring the maintenance of genomic integrity.Radiation and chemicals can cause DNA strand breaks by directly damaging the DNA structure or indirectly through the production of reactive oxygen species ROS . Ionizing radiation, such as X-rays and gamma rays, can cause both SSBs and DSBs by inducing the formation of free radicals that attack the DNA molecule. Ultraviolet UV radiation can cause the formation of pyrimidine dimers, which distort the DNA helix and lead to SSBs. Chemical agents, such as alkylating agents, can also cause DNA strand breaks by adding alkyl groups to the DNA bases, leading to mispairing and strand breaks.In summary, DNA strand breaks can have severe consequences on cell functions, leading to mutations, genomic instability, and cell death if not repaired. Nucleic acids play a vital role in DNA repair mechanisms, which help maintain genomic integrity. Exposure to radiation or chemicals can cause DNA strand breaks, highlighting the importance of understanding and mitigating the effects of these agents on DNA and cellular health.