DNA separated from one cell, when introduced in another cell, is able

1.	DNA separated from one cell, when introduced in another cell, is able to bestow some of the properties of the former to the latter. What is this change called in technical terms? Describe the experiment evidences which led to the discovery of the above phenomenon.
Answer» The change is called transformation. Transforming Principle ▪ Frederick Griffith (1928) conducted experiments with Streptococcus pneumoniae (bacterium causing pneumonia). ▪ He observed two strains of this bacterium—one forming smooth shiny colonies (S-type) with capsule, while other forming rough colonies (R-type) without capsule. ▪ When live S-type cells were injected into mice, they died due to pneumonia. ▪ When live R-type cells were injected into mice, they survived. ▪ When heat-killed S-type cells were injected into mice, they survived and there were no symptoms of pnuemonia. ▪ When heat-killed S-type cells were mixed with live R-type cells and injected into mice, they died due to unexpected symptoms of pneumonia and live S-type cells were obtained from mice. ▪ He concluded that heat-killed S-type bacteria caused a transformation of the R-type bacteria into S-type bacteria but he was not able to understand the cause of this bacterial transformation.

DNA separated from one cell, when introduced in another cell, is able to bestow some of the properties of the former to the latter. What is this change called in technical terms? Describe the experiment evidences which led to the discovery of the above phenomenon.

Answer»

The change is called transformation.

Transforming Principle

▪ Frederick Griffith (1928) conducted experiments with Streptococcus pneumoniae (bacterium causing pneumonia).

▪ He observed two strains of this bacterium—one forming smooth shiny colonies (S-type) with capsule, while other forming rough colonies (R-type) without capsule.

▪ When live S-type cells were injected into mice, they died due to pneumonia.

▪ When live R-type cells were injected into mice, they survived.

▪ When heat-killed S-type cells were injected into mice, they survived and there were no symptoms of pnuemonia.

▪ When heat-killed S-type cells were mixed with live R-type cells and injected into mice, they died due to unexpected symptoms of pneumonia and live S-type cells were obtained from mice.

▪ He concluded that heat-killed S-type bacteria caused a transformation of the R-type bacteria into S-type bacteria but he was not able to understand the cause of this bacterial transformation.

DNA separated from one cell, when introduced in another cell, is able to bestow some of the properties of the former to the latter. What is this change called in technical terms? Describe the experiment evidences which led to the discovery of the above phenomenon.

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