Trans for mation experiment was first performed on which bacteria?[2002]a)E.colib)Diplococcus pneumoniaec)Salmonellad)Pasteurella pestisCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

First perfomed by Griffith on Streptococcus pneumoniae in 1928.Ncert lines. Hence, option B is correct.

Answer

Answer

Explanation:
Transformation is a process in which foreign DNA, usually in the form of plasmids, is taken up and incorporated into the genome of a bacterial cell. This phenomenon was first observed in the bacterium Diplococcus pneumoniae.

Historical Background:
- The discovery of transformation can be attributed to Frederick Griffith, who was studying the pathogenicity of Diplococcus pneumoniae in 1928.
- Griffith observed that non-pathogenic strains of the bacterium could be transformed into pathogenic strains when they were in close contact with heat-killed pathogenic strains.
- This led to the hypothesis that the heat-killed bacteria released a transforming principle that could transfer genetic information to the live non-pathogenic bacteria.

Griffith's Experiment:
- Griffith conducted an experiment using two strains of Diplococcus pneumoniae: a non-pathogenic strain (R strain) and a pathogenic strain (S strain).
- He injected mice with four different combinations: live R strain, heat-killed S strain, a mixture of live R strain and heat-killed S strain, and a control group with no injection.
- The mice injected with the mixture of live R strain and heat-killed S strain died, and upon examination, Griffith found live pathogenic S strain bacteria in their bodies.
- This suggested that the live R strain bacteria had been transformed into the pathogenic S strain.

Significance of the Experiment:
- Griffith's experiment provided the first evidence of horizontal gene transfer in bacteria, which challenged the prevailing belief that genetic material was fixed and unchangeable.
- It laid the foundation for further studies in DNA transformation and the discovery of other mechanisms of genetic transfer, such as conjugation and transduction.

Conclusion:
In summary, the transformation experiment was first performed on Diplococcus pneumoniae, as observed by Frederick Griffith in 1928. This groundbreaking experiment demonstrated the transfer of genetic material between bacterial strains and paved the way for further research in the field of bacterial genetics.

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