NEETZoologyMolecular Basis of Inheritance
What happened to the mice injected with the mixture of heat-killed S and live R bacteria?
Options
- AThe mice survived
- BThe mice developed pneumonia
- CThe mice became heat-resistant
- DThe mice died
Correct answer
D. The mice died
Step-by-step solution
This is because the S strain bacteria have a mucous (polysaccharide) coat, while R strain does not. Mice infected with the S strain (virulent) die from pneumonia infection but mice infected with the R strain do not develop pneumonia. Griffith was able to kill bacteria by heating them. He observed that heat-killed S strain bacteria injected into mice did not kill them. When he injected a mixture of heat-killed S and live R bacteria, the mice died. Moreover, he recovered living S bacteria from the dead mice. He concl