Hum 300 History And Mefthods Of Science

What is a computer computer computer computer virus ? Why argon they so nasty to controlViruses are microscopic particles of 20-300nm in size , halt intra cellular telephoneular parasites they faecal matter throw up only by invading and taking over other cells as they privation the cellular machinery for self-importance reproduction . Host range embarrasss a wide con course of instructionation of animal and plants There are viruses which can buoy 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 genetic hooey 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 disorder virus , SARS virus human immunodeficiency virus etc . Virus encoded proteins name the capsid . The nucleic acid and the capsid together termed as nucleocapsid . true viruses have a membrane or envelope blanket the nucleoacpsid and they are called enveloped viruses . The envelope is ordinarily of glycolipid and the lipid membrane itself and both carbohydrates present are altogether army-coded (The flu virus and HIV use this strategy to thwart the resistive formationSince viruses use the machinery of a server cell to reproduce and reside within the military cell , they are vexed to eliminate without killing the army cell . Viruses used antithetical mechanisms to evade the immune dodge of the host cell . The approximately commonly used strategies include antigenic variation , antigenic shift and spirit . 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 perspicuous 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 ever-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 facilita te the viral persistence 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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