Carbohydrates, proteins, and lipids are three major classes of biomolecules that play essential roles in biological systems. Each class has distinct functional groups and properties that contribute to their specific functions in living organisms.1. Carbohydrates:Functional groups: Carbohydrates primarily consist of carbon, hydrogen, and oxygen atoms, with a general formula of Cn H2O n. They contain hydroxyl -OH groups and an aldehyde R-CHO or ketone R-CO-R functional group.Properties: Carbohydrates are polar molecules due to the presence of hydroxyl groups, which can form hydrogen bonds. They are highly soluble in water and can exist as monosaccharides simple sugars , disaccharides, oligosaccharides, or polysaccharides complex carbohydrates .Roles in biological systems: Carbohydrates serve as an essential energy source for living organisms. They also play a role in cell signaling, cell recognition, and structural support. For example, cellulose, a polysaccharide, provides structural support in plant cell walls, while glycogen serves as an energy storage molecule in animals.2. Proteins:Functional groups: Proteins are composed of amino acids, which contain an amino group -NH2 , a carboxyl group -COOH , and a variable side chain R group that determines the properties of each amino acid.Properties: Proteins exhibit a wide range of properties due to the diverse nature of amino acid side chains. They can be polar, nonpolar, acidic, or basic, depending on the R group. Proteins can form complex structures, such as alpha-helices and beta-sheets, through hydrogen bonding and other interactions between amino acids.Roles in biological systems: Proteins are the most diverse class of biomolecules and perform numerous functions in living organisms. They serve as enzymes, which catalyze chemical reactions, structural components e.g., collagen in connective tissues , transporters e.g., hemoglobin for oxygen transport , and signaling molecules e.g., hormones and receptors . Proteins also play a crucial role in the immune system as antibodies.3. Lipids:Functional groups: Lipids are composed of hydrocarbon chains or rings with various functional groups, such as carboxyl -COOH , hydroxyl -OH , or phosphate -PO4 groups. The most common lipids are triglycerides, phospholipids, and sterols.Properties: Lipids are predominantly nonpolar and hydrophobic due to the presence of long hydrocarbon chains. They are insoluble in water but soluble in nonpolar solvents. Some lipids, like phospholipids, have amphipathic properties, with a polar head group and nonpolar tail.Roles in biological systems: Lipids serve as an essential energy storage molecule, with triglycerides being the primary form of stored energy in animals. They also provide structural support and form the basis of cell membranes phospholipids . Lipids play a role in cell signaling, with sterols like cholesterol serving as precursors for steroid hormones. Additionally, lipids function as insulation and protection for organs and contribute to the absorption of fat-soluble vitamins.In summary, the differences in functional groups and properties of carbohydrates, proteins, and lipids contribute to their diverse roles in biological systems. Carbohydrates primarily function as an energy source and structural support, proteins serve as enzymes, structural components, and signaling molecules, and lipids provide energy storage, structural support in cell membranes, and signaling functions.