1.) it serves as a framework of the cell.meaning it helps to provide shape and make the cell structure to at least become a bit solid in morphology and that is also the fynction of the skeleton.of course cytoskeleton is not producing marrow and it does not contain or absorb Iron phosphorus and the like...Cytoskeleton is never as hard as our skeletons and if our skeleton is inside and between our muscles the cytoskeleton is inside the plasma membrane and found in the cytoplasm of the cell.in addition, they the cytosk. are not that compacted and very connected to each other or not orderly connected unlike the skeleton of the humans. they both have CaCO3 content.
2.)well they will not be able to grow more bigger and develop some of their supposed to be characterics as they grow. They may also not survive for a long time since they may need to grow. But if theyb remain as that then they may be called Giant Prokaryotic cell....A new discovery huh....No just joking for my latter answer.
3.)Because they don't grow at all because they do not undergo cell division for cell growth. They don't have membrane bound organelles just like of the eukaryotic cells of animals like us...It is needed for organism to grow and divide. the may undergo division but for producing only one that is the same as they are either by fission or budding.Well if a remember some of the answers of these questions i'll gladly return again and answer your question for some follow-up.