The Process of Restoring DNA After Damage. Genomes Are Subject to Damage by Chemical and Physical Agents in the Environment (e.g. Uv and Ionizing Radiations Chemical Mutagens Fungal and Bacterial Toxins Etc.) and by Free Radicals or Alkylating Agents Endogenously Generated in Metabolism. DNA Is Also Damaged Because of Errors During Its Replication. a Variety of Different DNA Repair Pathways Have Been Reported That Include Direct Reversal Base Excision Repair Nucleotide Excision Repair Photoreactivation Bypass Double Strand Break Repair Pathway and Mismatch Repair Pathway.
Any Process in Which a New Genotype Is Formed by Reassortment of Genes Resulting in Gene Combinations Different From Those That Were Present in the Parents. in Eukaryotes Genetic Recombination Can Occur by Chromosome Assortment Intrachromosomal Recombination or Nonreciprocal Interchromosomal Recombination. Intrachromosomal Recombination Occurs by Crossing Over. in Bacteria It May Occur by Genetic Transformation Conjugation Transduction or F Duction.
The Cellular DNA Metabolic Process Resulting in the Formation of DNA Deoxyribonucleic Acid One of the Two Main Types of Nucleic Acid Consisting of a Long Unbranched Macromolecule Formed From One or Two Strands of Linked Deoxyribonucleotides the 3' Phosphate Group of Each Constituent Deoxyribonucleotide Being Joined in 3' 5' Phosphodiester Linkage to the 5' Hydroxyl Group of the Deoxyribose Moiety of the Next One.
Catalysis of the Formation of a Phosphodiester Bond Between the 3' Hydroxyl Group At the End of One DNA Chain and the 5' Phosphate Group At the End of Another. This Reaction Requires an Energy Source Such As ATP or Nad+.