Describe Frederick Griffth's experiment to show transformation in bacteria.

Explanation

In 1928 Griffith working on the pathogencity of streptoccus pneeumoniae discovered a process called transformation . This bacterium is responsible for a form of pneumonia , killing mice . There are two strains of bacteria are virulent type and kill the mice while rough strain bacteria are avirulent type and do not kill the mice . If live rough strain bacteria (R) are injected the mouse does not die . When livr smooth bacteria are injected the mouse dies . But if heat killed smooth bacteria (S) are injected , the mouse does not die. If a mixture of heat killed smooth bacteria (S) and live rough bacteria (R) is injected into the mice it dies. Some property of heat killed smooth bacteria had transformed R bacterium to become virulent types . This activity was called terransforming principle Griffifth .
In 1944. Avery MacLeod and Mc carty extended Griffith experiment to identify the trans forming principle . They mixed .R. stra\in with DNA extracted from .S. strain of bacteria . When the enzyme (DNA ase ) which digest or breaks down DNA was added to this mixtures , there was no transformation of R to S type , but when the enzyme proteases that digest proteins was added to them medium the transforming principle was DNA .