So what exactly differentiates one blood type from another blood type? So essentially, on the membranes of our red blood cells, there are specific antigens, more specifically specific glycoproteins that are expressed and it's the type of glycoprotein on the cell membrane of the red blood cell that determines your blood type group. So let's take a look at the following three diagrams. So this is the cell membrane of our red blood cells. Now in an individual who has the O type, they have the O antigen. An individual who has the A type blood, they have the A antigen.