(i) Nucleus: Nucleus is enclosed by a double-membrane nuclear envelope. The space between the two membranes is called the perinuclear space. The perinuclear space forms a barrier between the nucleic materials and cytoplasmic materials. The outer membrane is usually continuous with the endoplasmic reticulum. Ribosomes are present on the outer membrane of nuclear envelope.
(ii) Centrosome: Centrosome usually contains two cylindrical structures which are called centrioles. They are surrounded by amorphous pericentriolar materials.
