: Protoplasm is the living substances of cells, including both nucleoplasm and cytoplasm as well as various organelles found in these media. Plasma membrane forms the outermost boundary of cytoplasm which separates it from the extracellular environment and controls the entrance and exit of molecules and ions. Ectoplasm is the portion of cytoplasm which is near the plasmalemma. Endoplasm, inner part of cytoplasm. Ectoderm is the outer layer of cells in a developing embryo.