Hey, good to see you again. Here are five important functions of proteins: 1. Enzymes: Proteins act as biological catalysts, speeding up chemical reactions in the body. For example, amylase breaks down starch. 2. Structure: They provide structural support to cells and tissues. Collagen is a key protein in skin and bones. 3. Transport: Proteins can move molecules within cells or throughout the body. Hemoglobin transports oxygen in the blood. 4. Immunity: Antibodies, which are proteins, defend the body against pathogens like bacteria and viruses. 5. Signaling: Some proteins act as hormones or receptors, transmitting signals between cells. Insulin regulates blood sugar.