The first virus to be purified was the tobacco mosaic virus (TMV). In 1935, American biochemist Wendell Meredith Stanley crystallized the tobacco mosaic virus. He found that the purified virus was primarily composed of protein and could still cause disease in plants. He was awarded the Nobel Prize in 1946 for this discovery.

• Purified/Crystallized: Tobacco Mosaic Virus (TMV).

• Scientist: Wendell M. Stanley (1935).

• Significance: Proved viruses could be crystallized and studied as chemical molecules.

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