As cells become more specialized, they may contain organelles that are not common to all cells. Since they are not common to all cells, and thus not necessary for all factories. Below are some cell structures that are not common to all cells. The design and shape of a cell is very much dictated by its function and the conditions under which it works. Unicellular organisms tend to have fairly complex cells, which makes sense considering that these organisms must depend on only one cell to do everything.
Multicellular organisms exhibit much greater specialization.
Red blood cells, for instance, have disklike flattened membranes. This shape gives them a maximum amount of surface area while still remaining smooth enough to slide through the smallest capillaries. Because red blood cells are manufactured for limited-time use, they have lost nearly all of their internal organelles, including nuclei. Consequently, they are very long and have branches that enable them to connect to other nerve cells. Gland cells, like the cells found in the pancreas, are filled with Golgi apparati.