1. The Discovery of Virus Bio 2nd Quarter

2. Ukraine, about 100 years ago. . . Tobacco plants showed odd mottling and discoloration. This puzzled a lot of scientists during that time as they found no bacteria within the leaves… Mottling- formation of odd spots This phenomenon is called the Tobacco mosaic virus. This marked the first evidence of the existence of viruses. . .

3. PEOPLE WHO HELPED IN THE DISCOVERY: Adolf Meyer German Scientist Concluded that the phenomenon is of bacterial origin. MartinusBeijerinick Dutch Scientist Called these infectious agents “virus”.* He thought of virus as liquid in nature. Wendell Stanley American Scientist Corrected Martinus by stating that viruses are particulate, not liquid. DimitriIwanowski Russian Scientist Filtered virus-infected tobacco leaf extracts using Chamberland filter candles. Concluded that the phenomenon is made by toxins of bacteria. *Virus- From the latin word “virus” which means ‘poison.’

4. AFTER THAT… On 1931, Ernst Ruska invented the Electron Microscope. It provided improved magnification. German physician and biologist Helmut Ruska finally observed viruses. Scientists have been able to give viruses a description. The first Electron Microscope Better view of a virus In conclusion: What is a virus? “A virus is a noncellular particle made up of genetic material and protein that can invade living things.”

5. Virus, living or nonliving? Q: If viruses are noncellular, are they living things? A: There is no correct answer for that yet because of the fact that all living things must be made up of cells. However, they have the nature of invading other living things. They also have genes and can reproduce provided that they are inside a host cell. Because of this, they are described as “organisms at the edge of life”.

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