question_answer

Directions : (31 - 35)

Read the passage given below and answer the following questions.

In 1928, Frederick Griffith, in a series of experiments with Streptococcus pneumoniae or Diplococus or Pneumococcus i.e., bacterium responsible for the disease pneumonia, witnessed a miraculous transformation in the bacteria. During the course of his experiment, a living organism i.e., bacteria had changed in physical form. When Streptococcus pneumoniae bacteria are grown on a culture plate, some produce smooth shiny colonies (S) while others produce rough colonies (R). This is because the S strain bacteria have a mucous i.e.. polysaccharide coat, while R strain does not. Mice infected with the S strain (virulent or pathogenic) die from pneumonia infection but mice infected with the R strain (nonvirulent or non-pathogenic) 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.

What happened when heat killed S cells along with live R cells were injected into mice?

A) Mice survived and showed live S cells

B) Mice died and showed, S cells

C) Mice survived and showed live R cells

D) Mice died and showed dead S cells