Nucleases catalyze the hydrolysis of phosphodiester bonds in nucleic acids (DNA and RNA). This means they break down nucleic acids by adding a water molecule across the phosphodiester bond, which links the nucleotide monomers together.

Here's a breakdown:

* Nucleic acids: DNA and RNA, made up of long chains of nucleotides.

* Phosphodiester bond: The bond that links the nucleotides in a nucleic acid chain.

* Hydrolysis: A chemical reaction where a water molecule is added to break a bond.

Types of Nucleases:

Nucleases are categorized based on their activity:

* Exonucleases: Remove nucleotides from the ends of a nucleic acid chain.

* Endonucleases: Break phosphodiester bonds within a nucleic acid chain.

Examples of Nuclease Functions:

* DNA replication and repair: Endonucleases are involved in removing damaged or mismatched nucleotides during DNA replication and repair.

* RNA processing: Exonucleases play a role in trimming and degrading RNA transcripts.

* Immune system: Nucleases in the immune system degrade viral DNA and RNA.

In summary, nucleases are enzymes that break down nucleic acids by hydrolyzing the phosphodiester bonds between nucleotides.