NEET Botany Molecular Basis of Inheritance Questions Solved


In a series of experiments with Streptococcus and mice F. Griffith concluded that

R-strain bacteria had been transformed. Explain.

1. Griffith experimented with Streptococcus Pnuemoniae, a bacterium that causes 

pneumonia on bacterial transformation.

2. There are two different strains of this bacterium, one forming smooth colonies 

protected by a polysaccharide coat (S-Strain) and the other forming rough colonies


3. The S-strain bacteria are virulent and the R-strain bacteria are non-virulent i.e.

they do not cause disease.

4. He injected live R-strain bacteria into mice, the mice did not die.

5. He injected live S-strain bacteria into mice, they died due to pneumonia.

6. The mice injected with heat killed S-strain bacteria survived.

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