Proteins play major roles in the body. Proteins are responsible for the growth and repair of cells. Proteins are the structural building blocks for most tissues in the body, such as red blood cells. Proteins are needed so antibodies can work properly in order to fight infections within the body. Enzymes are proteins. Enzymes are important because they allow speed up the rate of chemical reactions within the body (hence, they are biological catalysts). Without enzymes, the body could not respond to environmental changes fast enough to sustain life. Last, but not least, proteins serve as canals to allow good things into the cell and prevent harmful substances from entering.
Each cell has a particular glycoprotein structure based on its need to attract or repel membrane traffic. (Jeffrey Radecki M.D. and Susan Kim M.D., "Protein." Gale Group, 2004)
Proteins are one of the four major biomolecules in our bodies (in addition to carbohydrates, nucleic acids, and lipids). Amino acids are the building blocks of protein. DNA, RNA (m, t, and r), and ribosomes work together to make proteins during protein synthesis.