Q. In which of the following case, mice will remain alive in Griffith's transforming experiments?
Solution:
Transforming Principle (by Frederick Griffith, 1928)
- Frederick Griffith has done experiments on bacteria Streptococcus pneumonia. This bacteria causes pneumonia.
- Griffith has observed the change in the physical form of the bacteria during the experiments.
- Streptococcus pneumonia produces 2 types of colonies :
Smooth and shiny colonies (S - strain or virulent strain) - Bacteria possess mucous
(polysaccharide) coat.
Rough colonies (R - strain) - Bacteria lacks mucous coat.
Step 1 S -strain injected into the mice Mice die Step 2 R -strain injected into the mice Mice live Step 3 Heat killed S -strain injected into the mice Mice live Step 4 Heat killed S -strain + R -strain injected into the mice Mice die
| Step 1 | S -strain injected into the mice | Mice die |
| Step 2 | R -strain injected into the mice | Mice live |
| Step 3 | Heat killed S -strain injected into the mice | Mice live |
| Step 4 | Heat killed S -strain + R -strain injected into the mice | Mice die |