Viruses are microscopic parasites that infect cells of biological organisms. Viruses are obligate parasites, this is because viruses can only reproduce in living material by invading and utilizing living cells because the virus does not have cellular equipment to reproduce itself.
Usually the virus contains a small amount of nucleic acid (DNA or RNA, but not a combination of both) which is covered in a kind of protective material consisting of proteins, lipids, glycoproteins, or a combination of the three. The viral genome will be expressed to be both a protein used to load genetic material and proteins needed in its life cycle.
The term virus usually refers to particles that infect cells of eukaryotes (multicellular organisms and many types of single cell organisms), while the term bacteriophage or phage is used for types that attack prokaryotic cell types (bacteria and other cellless nuclei) .
Viruses are often debated as living beings because they cannot carry out their biological functions freely if they are not in the host cell. Because of its distinctive characteristics, viruses are always associated with certain diseases, both in humans (eg influenza and HIV viruses), animals (eg bird flu viruses), or plants (eg tobacco mosaic virus / TMV).
Structure of the Body of the Virus
- Form of Virus
At this time there are many kinds of viruses known. Some are rod-shaped (elongated), oval, round, cylindrical and some resemble the letter T.
- Virus body parts
In general, the body structure of the virus is divided into the outside and the inside (core).
- Outer body
a.1. The head of the virus is rectangular in that it contains a viral core in the form of nucleic acid.
a.2. The viral tail functions as an infection device, to attach the virus body to the host.
a.3. Viral tail fibers as part of the recipient of stimuli.
a.4. The capsid that covers the head and tail. consists of parts called capsomers and consists of identical monomer proteins, each of which consists of a polypeptide chain.
- Inner body (viral core)
The core of the virus is composed of core acids (nucleic acids) that contain DNA or RNA. In general, there is only one strand, except for influenza viruses that are up to 6 to 8 strands.