The reticulous endoplasmic reticulous is in the form of flattened sacs and interconected tubules that extend throughout the cytoplasm and continue in the clear loop, representing 10% of the cellular volume. On the other hand there is Golgi Apparatus, it is small stacked flat sacs formed by membranes inside the cytoplasm; while the Nuclear membrane is formed by phospholipids and surrounds the nucleus of a cell with a double-layer membrane composed by multiple pores.
