Accepts electrons from cytochrome c, ultimately transferring them to oxygen, forming H2O. in the process, 2 protons are pumped across the membrane. Complex IV is a terminal oxidoreductase, meaning that it transferes the elctrons to the terminal electron acceptor, which, in this case, is O2.
White blood cells called lymphocytes originate in the bone marrow but migrate to parts of the lymphatic system such as the lymph nodes, spleen, and thymus. There are two main types of lymphatic cells, T cells and B cells.
B lymphocytes are involved in humoral immunity, i.e. the production of antibodies. A small, mature B lymphocyte can be activated by the binding of an antigen to specific cell-surface receptors. This induces proliferation of the cell, resulting in an expanded clone of cells specific for that antigen.