The functional groups present in biomolecules like proteins and nucleic acids play a crucial role in dictating their unique properties and functions in living systems. These functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In the case of proteins and nucleic acids, the functional groups are primarily found in their monomer units, which are amino acids for proteins and nucleotides for nucleic acids.1. Proteins: Proteins are composed of amino acids, which contain an amino group -NH2 , a carboxyl group -COOH , and a side chain R group that is unique to each amino acid. The R group determines the properties and functions of each amino acid, and ultimately, the protein itself. There are 20 common amino acids, each with a different R group, which can be classified into various categories based on their properties, such as polar, nonpolar, acidic, or basic.The sequence of amino acids in a protein determines its three-dimensional structure, which in turn dictates its function. The interactions between the R groups of amino acids, such as hydrogen bonding, ionic interactions, van der Waals forces, and disulfide bridges, help to stabilize the protein's structure. These interactions are influenced by the functional groups present in the R groups, which ultimately determine the protein's properties and functions in living systems.2. Nucleic Acids: Nucleic acids, such as DNA and RNA, are composed of nucleotides. Each nucleotide consists of a phosphate group, a sugar deoxyribose in DNA and ribose in RNA , and a nitrogenous base adenine, guanine, cytosine, and thymine in DNA; adenine, guanine, cytosine, and uracil in RNA . The functional groups present in nucleotides, particularly the nitrogenous bases, dictate their properties and functions in living systems.The nitrogenous bases in nucleic acids are responsible for base pairing, which is essential for the formation of the double helix structure of DNA and the secondary structure of RNA. Base pairing occurs through hydrogen bonding between the functional groups of the nitrogenous bases, with adenine pairing with thymine or uracil in RNA and guanine pairing with cytosine. This specific base pairing is crucial for the accurate replication and transcription of genetic information in living systems.In summary, the functional groups present in the monomer units of proteins and nucleic acids play a critical role in determining their unique properties and functions in living systems. These functional groups are responsible for the specific interactions and structural features that allow proteins and nucleic acids to perform their essential roles in various biological processes.