Considering Griffith experiment, answer the following.(a) Name the bacterium used.(b) Write conclusion of the experiment.

Answer:

(a) Streptococcus pneumoniae (Diplococcus pneumoniae, pneumococcus): the virulent smooth S-strain (with capsule) and the non-virulent rough R-strain (without capsule).

(b) Mice injected with a mixture of heat-killed S-strain and live R-strain died, and live S-strain bacteria were recovered from them. Griffith concluded that some ‘transforming principle’ passed from the heat-killed S-strain to the live R-strain and transformed it into the virulent S-strain. This is called transformation; later work (Avery, MacLeod and McCarty) showed the transforming principle is DNA.