A glycoprotein is a type of protein that has carbohydrate molecules attached to it. These carbohydrates, or sugars, can influence the protein's structure and function. Glycoproteins are found in various biological systems and play essential roles in processes such as cell recognition, signaling, and immune responses. Glycoproteins are important components of cell membranes and can be involved in the formation of antibodies and hormones. They are also crucial for the proper functioning of viruses, as many use glycoproteins to attach to host cells. Understanding glycoproteins is vital in fields like biochemistry and medicine.