Function of Nucleus

• The nucleus is known as the controller of a cell and its metabolic activities. If the nucleus is removed from a cell, the protoplasm will dry up and dies ultimately.
• The nucleus is responsible for the cell cycle, it regulates it.
• The nucleus plays an important role in transmitting hereditary traits from parent to offspring.
• The nucleus controls the protein and enzyme synthesis.
• The nucleus is the storehouse of DNA, RNA, and ribosomes.
• Replication of the nucleus is essential for cell replication.
• The nucleus directs cell differentiation by allowing certain particular sets of genes to operate.
• Ribosomes are formed in the nucleolus part of the nucleus.

The cell is the basic structural and functional unit of living organisms. In biology, the cell has the same central position as that of an atom in the physical sciences. The bodies of living organisms are made up of microscopic units called cells. Cells have evolved a variety of different lifestyles. Many organisms, such as bacteria (both archaebacteria and eubacteria), protozoa(e.g., amoeba), and yeasts consist of single cells (called unicellular organisms) that have the ability to perform a function like self-replication. More complex organisms, called multicellular organisms, those consists of collections of cells that perform particular functions.

Term cell was discovered by Robert Hook in his book Micrographia. The size of the cell is 10-16 micrometers. The shape of the cell may be polygonal, disc-like amoebic, thread-like, cuboid or irregular, oval, hexagonal, circular, branched, elongated, etc. The cells are too small to be seen with naked eyes. So, it is studied with the help of microscopes.