Question

Differentiate between the following:

S-strain and R-strain of Pneumococcus bacteria

Answer 1

Basis of Difference	S-strain	R-strain
Colony appearance	The S-strain forms smooth, shiny colonies.	The R-strain forms rough, dull colonies.
Capsule	The S-strain has a smooth polysaccharide capsule.	The R-strain lacks a polysaccharide capsule.
Virulence	The S-strain is virulent and can cause disease.	The R-strain is non-virulent and normally does not cause disease.
Effect on mice	Live S-strain bacteria cause pneumonia and kill mice.	Live R-strain bacteria do not cause pneumonia, so the mice survive.