Acquired Immunodeficiency Syndrome

INTRODUCTION

Viruses are infective organism that infect living cells in order to reproduce and live. The word virus is derived from a Latin word which translates as “Poison” or “Toxin”. Viruses typically consist of a nucleic acid molecule in a protein coat and are alive only inside the body of a host. Alone, they are rather inert. For about 100 years, the scientific community has repeatedly changed its collective mind over what viruses are. First seen as poisons, then as life-forms, then biological chemicals, viruses today are thought of as being in a gray area between living and nonliving: they cannot replicate on their own but can do so in living cells and can also affect the behavior of their hosts profoundly.

Among the various types of viruses, HIV is a retrovirus. Retrovirus is a family of incased viruses that replicate in a host cell through the process of reverse transcription. A retrovirus is a single-stranded RNA virus that stores its nucleic acid in the form of an mRNA genome and targets a host cell as an obligate parasite. The virus uses an enzyme reverse transcriptase to make DNA from its RNA strand as it enters the host cell. The newly formed virus DNA is incorporated in the host’s DNA using an enzyme called integrase. After it is inserted in the host’s genome, it is called a provirus. The cell then unknowingly transcribes the virus’ DNA and translated proteins necessary for the virus. The virus is difficult to detect until it affects the human cell.

An interesting thing about HIV is that while other viruses contain the gene for the enzymes they require within their nucleic acids, HIV directly has the enzyme RNA Transcriptase. The activity of the enzyme enables the genetic information of HIV to become integrated pe...

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... Along with this, evolution of viruses (changing surface antigen frequently) has made such diseases difficult to suppress. Extensive research in currently being done in the field and there is much hope that we can find a cure to the disease by the next couple of decades.

REFERENCES http://en.wikipedia.org/wiki/Retrovirus http://en.wikipedia.org/wiki/Virus#cite_note-Dimmock_p._49-3 http://www.encyclopedia.com/topic/virus.aspx http://www.niaid.nih.gov/topics/hivaids/understanding/biology/Pages/structure.aspx http://micro.magnet.fsu.edu/cells/viruses/hivvirus.html http://www.youtube.com/watch?v=v5LGqi-8eZg http://www.youtube.com/watch?v=RO8MP3wMvqg http://en.wikipedia.org/wiki/Table_of_clinically_important_viruses http://www.thebody.com/content/art39393.html http://www.niaid.nih.gov/topics/HIVAIDS/Understanding/Biology/pages/hivreplicationcycle.aspx