Cell is the structural and function unit of life. A cell varies in its shape and size. There are many cells in our body which ranges from a very small size to a large size. The shapes of the cells are different due to their role in different parts of our body. They can be longitudinal, cuboidal, spindle shaped and circular or irregular shape.
A cell may have a nucleus or no nucleus. A cell having nucleus is called nucleated cell whereas a cell having no nucleus is called enucleated .The Red Blood Cells when mature are having no nucleus. The prokaryotic cell has no proper nucleus .Therefore, their nuclear material is aggregated at a point called as nucleoid. However, a eukaryotic cell possesses proper nucleus wherein the genetic material i.e., DNA is present.
Cell performs all the functions of the body. It provides shape, strength and serves as factory for many life processes. A cell further forms to make a tissue which leads to formation of an organ. The organ is part of organ system and an individual rises when all organ systems work together synchronously. An individual who can interbreed is named as Specie.
A single cell does not mean it is a single but a single cell means that it is a complete organism. To carry out functions in a single cell, there are cellular structure called organelles. These organelles are made up of biomolecules such as carbohydrates, proteins, lipids and nucleic acids. The major organelle of a eukaryotic cell is nucleus, which controls all the functions of the cell. From transcription to movement of material from nucleus to cytoplasm is controlled by the nucleus. A single cell is a complete organism such as protozoa. Protozoa is a single celled organism, which performs all its activities by the help of its one cell. The digestion, reproduction, movement of materials, an excretion is all carried out by the single cell structure. The protozoa divide by binary fission, takes in food by endocytosis and removes waste products by the process of exocytosis. The endocytosis and exocytosis are both taking place even in a human cell when it comes to movement of materials across the membrane.
The various organelles are Golgi bodies, Endoplasmic Reticulum, Cytoplasm, Ribosomes, Nucleus, Cell Membrane, and Cytoskeleton etc. The Golgi apparatus is a processing unit where molecules of large size are broken down into molecules of small size. It is also called as post office of the cell. The material is processes, packaged and delivered to the required places. The Endoplasmic Reticulum is a network of tubules which synthesis proteins, lipids and carbohydrates. Ribosomes are protein factories that synthesis proteins with the help of a process called as translation. Cell Membrane is a boundary of phospholipids and proteins that protects the inner environment of the cell from the external environment. Nucleus has DNA which transfer characters of one generation to another generation. Cytoskeleton is a structure of tubules and filaments that provide the cell the strength, rigidity, shape, and makes the transfer of material convenient within in the cell.
You must be logged in to post a comment.