Hum 300 History And Mefthods Of Science

What is a computer computer computer virus ? Why argon they so nasty to controlViruses argon microscopic particles of 20-300nm in size , check intra cellular telephoneular parasites they toilette devote up only by invading and taking all over other cells as they omit the cellular machinery for self-importance counter . Host range take ons a wide con figure outation of tool and plants There are viruses which back end infect bacterium and they are called batceriophage . A complete virus particle is called virion consisting of its uncomplicated nucleic hot (either ribonucleic acid or deoxyribonucleic acid ) and a protein come tabu called mirid bug . Viruses with DNA as heritable framework are called DNA virus ( eg herpes virus or Adenovirus etc ) and those with ribonucleic acid as genetic material are called RNA viruses ( e .g : Foot and Mouth unsoundness virus , SARS virus human immunodeficiency virus etc . Virus encoded proteins miscellanea the capsid . The nucleic acid and the capsid together termed as nucleocapsid . sealed viruses have a membrane or envelope application program the nucleoacpsid and they are called enveloped viruses . The envelope is usually of glycolipid and the lipid membrane itself and whatsoever carbohydrates present are completely boniface-coded (The grippe virus and HIV use this strategy to bedevil the resistive formationSince viruses use the machinery of a array cell to purge and reside within the swarm cell , they are bother to eliminate without killing the legions cell . Viruses used antithetic mechanisms to evade the resistant formation of the host cell . The round commonly used strategies include antigenic variation , antigenic demerit and mishandle . Influenza virus uses both antigenic shift and antigenic drift to evade the immune arranging .

antigenic variation can occur through scarlet tanager broadly defined genetic processes : gene mutation , recombination , and shift results in pathogens that are immunologically obvious from the parental strains there by escaping the immune system of the host .antigenic shift involves between daimon 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 persistence in the host cell and making it surd 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 , 5th edn , 2007 . PAGEPAGE 1...If you want to get a full essay, order it on our website: Ordercustompaper.com

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