Viruses and their Structure

Bacteriophage Structure
Bacteriophage Structure

Viruses are non-living organisms that have recently been re-looked at. They are not living because they do not contain any organelles, but they can replicate, as any living organism would do. Their structure is a very complex structure, which is made up of mostly proteins. They have three main parts to them. They are:
• The Capsid (external head) - The capsid is the protein shell that encloses the nucleic acid; with its enclosed nucleic acid, it is called the nucleocapsid, however the nucleocapsid is not found in all viruses. This shell is composed of protein organized in subunits known as capsomers. They are closely associated with the nucleic acid and reflect its configuration, either a rod-shaped helix or a polygon-shaped sphere. The capsid has three functions: 1) it protects the nucleic acid from digestion by enzymes, 2) contains special sites on its surface that allow the virion to attach to a host cell, and 3) provides proteins that enable the virion to penetrate the host cell membrane and, in some cases, to inject the infectious nucleic acid into the cell's cytoplasm. Under the right conditions, viral RNA in a liquid suspension of protein molecules will self-assemble a capsid to become a functional and infectious virus.
• The DNA or RNA, and the proteins – The DNA and RNA is the genetic information of the virus. Some viruses have DNA and some have RNA. This is stored within the capsid and, if applicable, in the nucleocapsid. They are strands in the head that hold all the genes and genetic information ready to be passed on to the next generation. The proteins enable the virus to carry out the very few life functions that it has, which is mostly reproduction.
• The neck and parts of the tail – The neck is there basically to support the virus to be able to stay. It has basically the same function as our spinal chord. The tail sheath is there to start the tail and to keep it in place, assisting the neck and protecting it, seeing as how the neck is too narrow to support itself. The tail fibers allow the virus to become mobile and to latch on to host cells. The end plate is there to hold the pins. The pins are used to inject the virus’ genetic information into the host cell.

Also, specific viruses, bacteriophages, which are viruses that only infect bacteria, have made their way into research facilities. When these viruses were first observed, the scientists observed that these viruses infect bacteria, instead of normal eukaryotic cells. When they saw this, they quickly divulged this information to the medical public. Because of this information, bacteriophages started to become the way to treat bacterial infections and anything else regarding bacteria. These are specifically helpful because these viruses only infect bacteria and not human cells. Therefore, they will not harm us in any way and instead help us by destroying all the bacteria that bypasses the 1st and 2nd line of defense.