The nuclear envelope is between the nucleus and the cytoplasm. It looks like a double membrane. It is suppose to separate the contents between the nucleus and the cytoplasm works with the nucleus by surrounding it.
nucleus
The nucleus is in the center of the cell. It is bounded tightly together by the envelope. The nucleus contains information of the reproduction and growth of the cell. linked together with chromosomes.
nucleolus
nucleolus is located in the nucleus. The structure of the nucleolus is a dense compound of RNA and protein. The function of it is that is synthesizes ribosomes by transcribing and assembling RNA. make small ribosomes.