What is a computer virus ? Why be they so uncorrectable to controlViruses are microscopic particles of 20-300nm in size , constipate intra cellular parasites they quarter throw up only by invading and winning over other cells as they wishing the cellular machinery for egotism reproduction . Host range includes a wide revolution of animal and plants There are viruses which can infect bacterium and they are called batceriophage . A complete virus particle is called virion consisting of its sincere nucleic acid (either ribonucleic acid or desoxyribonucleic acid ) and a protein rise up called mirid . Viruses with desoxyribonucleic acid as genetic genuine are called DNA virus ( eg herpes virus virus or Adenovirus etc ) and those with RNA as genetic material are called RNA viruses ( e .g : Foot and Mouth infirmity virus , SA RS virus HIV etc . Virus encoded proteins work out the capsid . The nucleic acid and the capsid together termed as nucleocapsid . true viruses have a tissue layer or gasbag covering the nucleoacpsid and they are called enveloped viruses . The envelope is normally of glycolipid and the lipid membrane itself and any carbohydrates present are merely host-coded (The Influenza virus and HIV use this strategy to table the repellent melodious arrangementSince viruses use the machinery of a host cell to reproduce and lodge in within the host cell , they are rough to close out without killing the host cell . Viruses used incompatible mechanisms to spoil the immune organisation of the host cell . The around unremarkably used strategies include antigenic variation , antigenic release and bearing . Influenza virus uses both antigenic arouse and antigenic drift to evade the immune system .
antigenic variation can occur through trey in general defined genetic processes : gene mutation , recombination , and slip results in pathogens that are immunologically distinct from the parental strains there by escaping the immune system of the host .Antigenic shift involves between ii unlike subtypes of the same virus coinfect a single cell and counterchange RNA segments to form a new subtype . Antigenic drift is by changing the surface protein mainly haemagglutinin and Neuraminidase proteins in subject area of influenza virus . Mutations in the RNA or DNA causes change in the surface protein and host immune system fails to identify the viral proteins and this will facilitate the viral patience in the host cell and making it elusive t o controlReferenceds Virology , David M .Knipe , Peter M Howley , Diane E Griffin , Robert A love , Malcom A Martin , Bernard Roizman , Stephan E Stratus , Source Lippincott Williams Wilkins (LWW , fifth edn , 2007 . PAGEPAGE 1...If you essential to get a full essay, order it on our website: OrderCustomPaper.com
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