Cell - Structure and Functions

(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:(i)Nuclear membrane:It is a double-layered membrane which separates the contents of the nucleus from the cytoplasm. The nuclear membrane has nuclear pores that allow the transfer of specific substances in and out of the nucleus. (ii)Nucleolus:It is a small spherical body that is not bound by any membrane. (iii)Chromosomes:These are thread-like structures that carry genes. Genes contain information necessary for the transfer of characteristics from the parents to the offspring. Thus, chromosomes play an important role in the inheritance of characteristics.