Question

When a mixture of debris from killed virulent bacteria and living non-virulent bacteria are injected into mice:

A. the mice are killed because the virulent bacteria are revived.
B. the mice are killed because the non-virulent bacteria are transformed into virulent bacteria.
C. half the mice are killed and the other half survive.
D. the mice survive for a period of a few weeks and then die from an unrelated illness.
E. the mice survive because none of the living bacteria are virulent.

Answer 1

Mice injected with a mixture of heat-killed virulent bacteria and live non-virulent bacteria died because the non-virulent bacteria were transformed into virulent bacteria due to the 'transforming principle' discovered by Frederick Griffith.

Step-by-step explanation:

When Frederick Griffith conducted his transformation experiments, he discovered a pivotal concept in molecular biology.

that were injected with a mixture of debris from killed virulent bacteria (S strain) and living non-virulent bacteria (R strain) ended up dying. Griffith found that, although the S strain bacteria had been heat-killed, their presence somehow transformed the live non-virulent R strain into a virulent form capable of causing the mice to die.

This outcome was unexpected because the heat-killed S strain on its own did not cause death in mice when injected. However, when combined with the live R strain, the result was a lethal combination.

This phenomenon was explained by the transformation principle, where genetic material from the dead S strain transferred to the living R strain, making it virulent.

Hence, the correct answer to the question posed is: B. The mice are killed because the non-virulent bacteria are transformed into virulent bacteria.