Amolecule is composed of chains of amino acids. this sequence of the amino acids determines the shape and the function of the molecule. identify the molecule.

A protein molecule is made from a long chain of these amino acids, each linked to its neighbor through a covalent peptide bond (Figure 3-1). Proteins are therefore also known as polypeptides. Each type of protein has a unique sequence of amino acids, exactly the same from one molecule to the next.

To minimize the chance of an adverse reaction during a transfusion, health care practitioners take several precautions. Before starting the transfusion, usually a few hours or even a few days beforehand, the person is cross-matched with the donor blood (not done for transfusions of plasma or platelets).