Though strictly speaking, an antibody is not the same as an immunoglobulin; B cells can produce two types of immunoglobulins-surface immunoglobulins, which are B cell receptors; and secreted immunoglobulins, which are antibodies. So antibodies are one of two classes of immunoglobulins.ach antibody binds to a specific antigen; an interaction similar to a lock and key. An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shape protein produced by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses.
About 95 percent of the dry weight of the red blood cell consists of hemoglobin, the substance necessary for oxygen transport. Hemoglobin is a protein; a molecule contains four polypeptide chains (a tetramer), each chain consisting of more than 140 amino acids.
Therefore, one molecule of hemoglobin can bind four molecules of oxygen. As each red blood cell contains about 280 million hemoglobin molecules, a single red blood cell can carry over 1 billion molecules of oxygen. Once again, that's a lot of oxygen! Cooperative Binding. Okay, so hemoglobin carries oxygen, but how does oxygen bind to hemoglobin? The way by which hemoglobin binds oxygen is referred to as cooperative binding. The binding of oxygen to hemoglobin makes it easier for more oxygen to bind. Let's consider an analogy.