Nucleus:

A prominent nucleus occurs in eukaryotic cells. In animal cells, it is present in the center while in mature plant cells, due to the formation of a large central vacuole, it is pushed to the side.

Structure of Nucleus:

The nucleus is bounded by a double membrane known as a nuclear envelope.

Nuclear Envelope:

The nuclear envelope contains many small pores that enable it to act as a differentially-permeable membrane.

Nucleoplasm:

Inside the nuclear envelope a granular matrix, the nucleoplasm, is present. The nucleoplasm contains one or two nucleoli (singular, nucleolus) and chromosomes.

Visibility of Nucleolus:

The nucleolus is usually visible as a dark spot and it is the site where ribosomal RNA is formed and assembled as ribosomes.

Chromosomes: One of the rods shaped bodies found in the nucleus of cells that contain genetic information (DNA) Chromosomes are visible only during cell division while during the interphase (non-dividing phase) of the cell they are in the form of fine thread-like structures known as chromatin Structure of DNA: Chromosomes are composed of Deoxyribonucleic acid (DNA) and histone proteins provide structural support to DNA for making the structure of the chromosome.

Messenger Ribonucleic Acid (mRNA):

DNA contains the message for the synthesis of specific proteins. According to this message, a molecule of messenger Ribonucleic Acid (mRNA) is synthesized. In this way, the message is handed over to mRNA, which carries it to ribosomes. Ribosomes manufacture specific proteins according to the message present on mRNA.

The function of DNA:

In this way, DNA controls all the activities of the cell and is also responsible for the transmission of characteristics to the next generation. That is why it is honored as hereditary material.

Main Function of Nucleus:

The nucleus is called the brain of the cell. The nucleus controls all the activities of the cell.

Note:

The prokaryotic cells do not contain a prominent nucleus rather their chromosome is made of DNA only and is submerged in the cytoplasm.