How many colors of blood are there and what are the causes for their color?

Answer 1

There are two well known types of "blood colors". The color of the blood is closely related to the oxygen molecules. O2 molecules can be bound in different ways: by the ferrous heme groups of the globins (e.g., myoglobin and hemoglobin); or by two Cu+ ions held in close proximity by six His side chains in hemocyanins. Fe2+ and Cu+ ions and ferrous heme groups free in solution do not bind reversibly; instead, they oxidized to the Fe3+ and Cu2+ forms. Under these circumstances, when Fe2+ is oxidized to Fe3+ acquires a red color, this is the reason why blood is red in upper organisms, those that have hemoglobin. On the other hand, when Cu+ oxidizes to Cu2+ turns to blueish color. In lower organisms (e.g., crustacea) the blood turns blueish when is exposed to oxygen. In resume, we have two blood colors, red and blueish, when it's oxidized.