What is nucleus?

Is a dense protoplasmic body that contains hereditary information for controlling cell activity.  It is the largest cell structure, oval, lies in median. Has double layer covering called nuclear membrane which has pore for the transfer of material.  The fluid like structure present in the nucleus is called nucleoplasm. It also contains one or more round like structure called nucleolus. The nucleus contain chromosome which are rod shape contain information for inheritance of features from parents to next generation in the form of DNA (deoxyribose nucleic acid) molecules. Chromosomes are composed of protein & DNA. The DNA contains information for constructing &organizing the cell. Functional segment of DNA are called gene. Chromatin materials are entangled to form thread like structure the chromosome.