Emman PerezJoey Torres

II-Sampaguita

latin “latin “virus” virus” refers to poison and other refers to poison and other noxious substancesnoxious substances

a small infectious agent that can a small infectious agent that can replicate only inside living cells of replicate only inside living cells of organismsorganisms

can infect ALL types of organisms can infect ALL types of organisms regardless of sizeregardless of size

Very hard to see using normal Very hard to see using normal microscopemicroscope

Most viruses have a diameter between Most viruses have a diameter between 10-300 nanometres10-300 nanometres

Have four main morphological virus Have four main morphological virus types:types:

1.1. Helical – spiral shapedHelical – spiral shaped2.2. Icosahedral – “near spherical”Icosahedral – “near spherical”3.3. Envelope – envelope themselves in modified cell membranesEnvelope – envelope themselves in modified cell membranes4.4. Complex – possess extra structures such as protein tails and complex outer Complex – possess extra structures such as protein tails and complex outer

walls.walls.

Still unclear to most scientistsStill unclear to most scientists Viruses do not leave any fossilsViruses do not leave any fossils They have to be untangled from their host They have to be untangled from their host

cellscells 3 main Hypotheses:3 main Hypotheses:

Regressive hypothesis Regressive hypothesis Cellular origin hypothesisCellular origin hypothesis Coevolution hypothesisCoevolution hypothesis

Louis Pasteur was unable to find a Louis Pasteur was unable to find a causative agent for rabiescausative agent for rabies

Charles ChamberlandCharles Chamberland Invented a filter which had pores smaller than Invented a filter which had pores smaller than

bacteriabacteria Dmitry IvanovskyDmitry Ivanovsky Tobacco Mosaic VirusTobacco Mosaic Virus

Martinus BeijerinckMartinus Beijerinck the filtered solution contained a new the filtered solution contained a new form of form of

infectious agentinfectious agent

Vaccination Cheap and effective way of preventing

infections Improves immunity

Antiviral Drugs Nucleoside analogues DNA Chain Termination

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/