Question

A series of experiments were conducted by Frederick Griffith in 1928, on transforming principle with:

• A. Streptococcus pneumoniae
• B. Escherichia coli
• C. Bacillus thuringiensis
• D. Salmonella typhimurium

Answer 1

Answer: (A)

Streptococcus pneumoniae

Answer 2

Frederick Griffith's experiments were instrumental in understanding the phenomenon of bacterial transformation. He studied different strains of Streptococcus pneumoniae, specifically the virulent (pathogenic) strain and the non-virulent (avirulent) strain.
In his experiments, Griffith observed that when he injected mice with the heat-killed virulent strain of Streptococcus pneumoniae, the mice remained healthy and survived. Similarly, when he injected mice with the live avirulent strain, the mice also remained healthy.
However, Griffith discovered something intriguing when he injected mice with a mixture of the heat-killed virulent strain and the live avirulent strain. The mice became sick and died, and upon examination, he found live virulent bacteria in their bodies. This led Griffith to propose the concept of transformation, where the genetic material from the heat-killed virulent strain somehow transformed the avirulent strain into a virulent form.