Hum 300 History And Mefthods Of Science

What is a computer computer computer virus ? Why argon they so nasty to controlViruses are microscopic particles of 20-300nm in size , control intra cellular telephoneular parasites they croupe throw up only by invading and taking over other cells as they need the cellular machinery for self-importance reproduction . Host range holds a wide con doation of animal and plants There are viruses which fag infect bacterium and they are called batceriophage . A complete virus particle is called virion consisting of its uncomplicated nucleic acid (either ribonucleic acid or desoxyribonucleic acid ) and a protein come out called capsid . Viruses with DNA as inherited material are called DNA virus ( eg herpes virus or Adenovirus etc ) and those with RNA as genetic material are called RNA viruses ( e .g : Foot and Mouth complai nt virus , SARS virus human immunodeficiency virus etc . Virus encoded proteins miscellany the capsid . The nucleic acid and the capsid together termed as nucleocapsid . trusted viruses have a membrane or envelope finishing the nucleoacpsid and they are called enveloped viruses . The envelope is ordinarily of glycolipid and the lipid membrane itself and either carbohydrates present are altogether military-coded (The flu virus and HIV use this strategy to thwart the resistive formationSince viruses use the machinery of a swarm cell to reproduce and reside within the legion cell , they are vexed to eliminate without killing the armament cell . Viruses used antithetical mechanisms to evade the immune establishment of the host cell . The approximately commonly used strategies include antigenic variation , antigenic shift and spoil . Influenza virus uses both antigenic shift and antigenic drift to evade the immune system .

antigenic variation can occur through cardinal broadly defined genetic processes : gene mutation , recombination , and shift results in pathogens that are immunologically hard-hitting from the parental strains there by escaping the immune system of the host .Antigenic shift involves between dickens different subtypes of the same virus coinfect a single cell and exchange RNA segments to form a new subtype . Antigenic drift is by changing the surface protein mainly haemagglutinin and Neuraminidase proteins in case 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 persistenc e in the host cell and making it voiceless to controlReferenceds Virology , David M .Knipe , Peter M Howley , Diane E Griffin , Robert A Lamb , Malcom A Martin , Bernard Roizman , Stephan E Stratus , Source Lippincott Williams Wilkins (LWW , fifth edn , 2007 . PAGEPAGE 1...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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