Question

Which of the following causes pneumonia in mice in Griffith's experiment?

• A. S-type (Smooth, Virulent)
• B. R-type (Rough, Non-virulent)
• C. Both A and B
• D. Heat-killed S-type only

Hint:

In Griffith's experiment, the transformation phenomenon was discovered when non-virulent bacteria (R-type) took up genetic material from heat-killed virulent bacteria (S-type), turning into virulent bacteria capable of causing disease.

Answer 1

The Correct Option is A

In Griffith's experiment, he used two strains of Streptococcus pneumoniae bacteria: the S-type (smooth and virulent) and the R-type (rough and non-virulent).
- The S-type is virulent and causes pneumonia in mice.
- The R-type does not cause pneumonia on its own because it is non-virulent.
- Heat-killed S-type did not cause pneumonia by itself, but when mixed with live R-type, it could transfer its virulence to the R-type in a process known as transformation, leading to the development of pneumonia. Thus, the correct answer is option (A) S-type (Smooth, Virulent).