1. nucleus is the main and the important organelle of a cell and is in spherical in shape.  
2.  it determines the characteristics of an organisms. 
3. nucleus help in the process of cell division and reproduction as it is having chromosomes for storing of genetic information. 
4. it has a semi solid substance called nuclei plasma inside it. thread like structures called chromosomes are present in the nuclei plasma. these thread like substances help in the carrying the genes. 
5. if the nucleus is removed from the cell the transfer of genetic material would be affected and this is in turn affects cell division. 
6. even the control over all the activities would be disturbed and the ill effects will be seen in the organisms.