Viruses Flashcards
History, structure, prop. And classification
who discovered Viruses??
D.J Ivanowsky
how did Ivanowsky discover the virus which he regarded as “small microorganisms
He found an infectious extract from tobacco plants with the T.M.DISEASE. He discovered that these tobacco retained their infectivity after passage through a filter paper capable of preventing the passage of bacteria…. He concluded they were small Microorganism
describe M.W.Beijenrick’s contribution to virus???
after these same ‘small microorganisms ‘ were precipitates by alcohol and when passed through agargel…..they still retained their infectious power. He hence concluded that they weren’t living organisms but rather “fluid infections principle”
describe W.M.Stanley’s contribution to virus discovery??
He showed that these viruses can be crystallized and the crystals consists largely of proteins. meaning they are protein molecules… Hence his major contribution was showing that viruses are protein molecules.
what’s the first virus to be discovered ??
Tobacco Mosaic Disease
name the groupings of viruses??
Cubic Symmetry , Helical symmetry and Complex structures
Describe the cubic symmetry of virus
they have an icosahedral patters and are most efficient for subunits In a shell….it has 20 units. 12 vertices….. and 5 folds…. 3 folds…..and 2 fold axes of rotational symmetry.
name three examples of Cubic Virus??
Adenovirus, Polio virus, and Rhino virus.
describe the helical symmetry of virus
such have protein subunits bounded in a periodic way winding it into a helix…
