I'm not sure if this answers my question. What I think of a cell is a three dimensional object surrounded by a cell membrane. Now if on looking at a cell 2 of microscope I can see the cytosol then it probably means that the cell membrane that should have been between the microscope and the cytosol is transparent but then how come at the same time I see the cell membrane in the same image as a dark boundary surrounding the cytosol.

Just one doubt, but people with aneuploidy have problems because their aneuploidy translates into some sort of protein imbalance, and that brings me back to my question

Thanks for your reply, can you add something more about the "self error checking" mechanism, maybe a link?.