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Possible Origin of Viruses. Emman Perez Joey Torres II-Sampaguita. Virus?. latin “ virus” refers to poison and other noxious substances a small infectious agent that can replicate only inside living cells of organisms can infect ALL types of organisms regardless of size. Structure.
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Possible Origin of Viruses Emman Perez Joey Torres II-Sampaguita
Virus? • latin “virus” refers to poison and other noxious substances • a small infectious agent that can replicate only inside living cells of organisms • can infect ALL types of organisms regardless of size
Structure • Very hard to see using normal microscope • Most viruses have a diameter between 10-300 nanometres • Have four main morphological virus types: • Helical – spiral shaped • Icosahedral – “near spherical” • Envelope – envelope themselves in modified cell membranes • Complex – possess extra structures such as protein tails and complex outer walls.
How did they start? • Still unclear to most scientists • Viruses do not leave any fossils • They have to be untangled from their host cells • 3 main Hypotheses: • Regressive hypothesis • Cellular origin hypothesis • Coevolution hypothesis
How do we spot viruses? • Louis Pasteur was unable to find a causative agent for rabies • Charles Chamberland • Invented a filter which had pores smaller than bacteria • Dmitry Ivanovsky • Tobacco Mosaic Virus • MartinusBeijerinck • the filtered solution contained a new form of infectious agent
How to prevent viruses • Vaccination • Cheap and effective way of preventing infections • Improves immunity • Antiviral Drugs • Nucleoside analogues • DNA Chain Termination
References • http://www.scientificamerican.com/article.cfm?id=experts-where-did-viruses-come-fr • http://en.wikipedia.org/wiki/Virus • http://www.bookrags.com/research/evolutionary-origin-of-bacteria-and-wmi/