Proteins are made from amino acids joined via peptide bonds. The endoplasmic reticulum, RNA, ribosomes, and Golgi apparatus all have a role in the formation, packaging and delivery of proteins within a cell.
Along with lipids and carbohydrates, protein serves as a vital part of our diet. In fact, there are nine essential amino acids. These are amino acids that our bodies cannot produce and must come from our diet.
Proteins serve many functions within an organism, such as mammals. Proteins are used to grow and repair tissues. They are needed to make enzymes (biological catalysts). Enzymes are important because, without them, many of the reactions within an organism would not happen fast enough to meet the demands of life. Proteins also form hormones, which transport chemical messages between tissues and organs. Proteins are also important building blocks of bone, carilage, muscle, skin, and blood.