(a) Cytoplasm:
It is a fluid that fills the cell and occurs between the plasma membrane and the nucleus. Cell organelles such as mitochondria, ribosomes, Golgi bodies, etc. are suspended in the cytoplasm. The cytoplasm helps in the exchange of materials between cell organelles.
(b) Nucleus of a cell:
The nucleus is a spherical structure generally present at the centre of a cell. The nucleus is
composed of the following components: