Question

Which of the following is the wrong sequential order, when the S or the R strain of the bacterium is injected into the mice?

• A. Mice -> S strain -> Dead
• B. Mice -> R strain -> Alive
• C. Mice -> Heat killed S strain -> Alive
• D. Mice -> Heat killed S strain + live R strain -> Alive

Answer 1

Answer:

D. Mice -> Heat killed S strain + live R strain -> Alive

When the heat killed S-strain of the bacterium is given along with the R strain to the mice, a process of transformation occurs. The heat killed S strain (avirulent) was able to transform the R strain (avirulent) to become a virulent strain. During this process of transformation, the heat killed S strained bacterium, transforms the R strain to produce the mucous(polysaccharide) and become virulent.