Question

The infective nature of tobacco mosaic disease was discovered by
A. Ivanowsky
B. Adolf Mayer
C. Beijerinck
D. Stanley

Answer 1

Hint: Tobacco mosaic virus (TMV) was the first virus to be discovered and even the first virus ever purified. It is responsible for the Tobacco mosaic disease. Symptoms caused by TMV include mosaic, mottling, necrosis, stunting, leaf curling, and yellowing of plant tissues. The symptoms depend on the age of the infected plant, the prevailing environmental conditions, the strain of the virus, and the genetic framework of the host plant.

Complete solution
Option A. Ivanowsky: Dmitri Ivanowsky was a Russian biologist. In 1892, he discovered and coined the term “virus,” which means venom or poisonous fluid. He recognised certain microbes, which caused tobacco mosaic disease and were found to be smaller in comparison to bacteria, as they passed through bacteria-proof filters.
Option A is correct.
Option B. Mayer: In 1882, Adolf Mayer was the first one to describe an important disease of tobacco, and he called it tobacco mosaic disease. He believed that it was caused by either a toxin or a very minute bacterium.
Option B is not correct.
Option C. Beijerinck: Martinus W. Beijerinck, was a Dutch microbiologist and botanist. He showed that the extract of the infected tobacco plants could give rise to infection in healthy plants. He called the fluid “Contagium vivum fluidum” (infectious living fluid). He is also known as the father of virology.
Option C is not correct.
Option D. Stanley: W.M. Stanley (1935) exhibited that viruses could be crystallised and their crystals comprise mainly of proteins. For this accomplishment he was awarded a shared Nobel Prize in chemistry in 1946 with John Northrop.
Option D is not correct.

Answer. Option A is correct

Note:
In 1884, Charles Chamberland (a French microbiologist) invented a filter – known today as the Chamberland filter, which consists of pores smaller than bacteria. Thus, he was able to pass a solution containing bacteria through the filter and completely separated them from the solution.