You have a slightly different enzyme than the A people, so you build a slightly different structure, and those of you that are AB have the enzyme from your mother, the other enzyme from your father, and now you make both of these structures in roughly equal proportions.
Vi imate nešto drugačiji enzim nego osobe iz A grupe pa vi imate nešto drugačiju strukturu, a vi koji imate AB grupu imate jedan enzim od svoje majke, drugi enzim od vašeg oca i sada imate obje te strukture u približno jednakim omjerima.