Size And Shape Virus
The virus has a microscopic size, which is between 25-300 μm (1 μm = 1 / 1,000,000 m). Viruses are the smallest size is a polio virus (poliovirus). The body length of only 25 lm. Viruses that are large is a virus attack bacteria that the body length of 100 μm and the tobacco mosaic virus (TMV) the length of the body 300 lm.Because of his size microscopic, virus can only be seen using a special microscope, the electron microscope. The virus began to be observed by electron microscopy in 1930.
The virus has an assortment of shapes. Some are round, rod, polihidris (polygons), and there is nothing like the letter T. Viruses that are round, such as influenza virus (Influenza virus) and the virus that causes AIDS (Human Immunodeficiency Virus / HIV).
Virus oval, for example rabies virus (Rabies virus). The rod-shaped viruses such as tobacco mosaic virus (Tobacco mosaic virus / TMV). Virus-shaped polihidris, for example Adenovirus (disease causing fever). While the T-shaped virus, for example, viruses that attack bacteria (bacteriophage or phage abbreviated).
Virus Structure And Function
The virus is not in the form of cells (acellular). Virus in the form of particles, called virions. Virions can be crystallized so it shows the characteristics of minerals rather than the characteristics of life. Therefore most scientists consider biological virus is not a living being. However, other biological scientists assume that the virus is a living creature.The reason, the virus can show the characteristic of life, ie reproduction, although it can only be done in the cells of other organisms. Therefore, instead of a cell, the virus does not have parts of cells, such as the plasma membrane, cytoplasm, and nucleus. Viruses consist of nucleic acid and protein coat.
The nucleic acid is the carrier of genetic information. Virus nucleic acid in the form of a single type of nucleic acid, ie DNA or RNA alone course. The genetic material can form a single chain or double chain. The chain can be circular or linear.
A protein coat (capsid) is a nucleic acid wrapper. The capsid is composed of protein molecules called capsomeres. The capsid is what gives the form of the virus. Capsid can be shaped rod which is an arrangement of helical (screw) of kapsomer, polyhedral shape (polygon), or complex-shaped.
Virus complex has a section called the head and tail. Head complex viruses have a polyhedral shape. In addition, complex viruses have an additional structure, namely the tail sheath, base plates and tail fibers. Slab base and tail fibers work when the virus attach to the cells it infects. Examples of complex viruses is the virus attack bacteria that form the letter T.
Combined nucleic acid and capsid is called a nucleocapsid. In some viruses, nucleocapsid surrounded by a membrane called the cover. Viral envelope composed of lipids and proteins. Cover virus serves as a protector of the virus. Viruses that do not have covers so-called naked viruses.
