A nuclease is an enzyme that breaks down nucleic acids, such as DNA and RNA, into smaller components. This process is essential for various biological functions, including DNA repair, replication, and the degradation of RNA molecules. Nucleases can be classified into two main types: exonucleases, which remove nucleotides from the ends of nucleic acid chains, and endonucleases, which cut nucleic acids at specific internal sites. Nucleases play a crucial role in cellular processes and are also utilized in laboratory techniques, such as molecular cloning and genetic engineering. By manipulating nucleic acids, researchers can study genes, develop therapies, and create genetically modified organisms.