Question

The beginning of understanding genetic transformation in bacteria was made by
A. Fredrick Griffith
B. Hershey and chase
C. Watson and crick
D. T.H Morgan

Answer 1

Hint: Genetic transformation is a process that involves the introduction and expression of a foreign gene in a host organism. This experiment, reported in 1928 was the first experiment suggesting that bacteria are capable of transferring genetic information and the process was known as transformation.

Complete answer: Fredrick Griffith was the first person who proved that bacteria transfers genetic information through transformation – the transformation was discovered in streptococcus pneumoniae. During the experiment, Griffith cultured streptococcus pneumoniae bacteria which gave 2 growth patterns. One culture plate slowed smooth shiny colonies (S) while others had rough colonies (R). ‘S’ strain bacteria had mucous, while ‘R’ strain bacteria lacked them.
Experiment:- Griffith injured both ‘S’ and ‘R’ strains to mice. The one which was injected with ‘S’ strain developed pneumonia and died, whereas the one with ‘R’ strain stayed alive. In the second stage, Griffith heated and chilled the S-strain bacteria and injected it into mice, but the mice stayed alive. He then mixed the heat-killed ‘S’ and live ‘R’ strains and on injecting this mixture, the mice died. Based on this observation Griffith concluded that the ‘R’ strain bacteria had been transformed by ‘S’ strain bacteria. The R strain inherited some transforming principle form the heat-killed s strain bacteria which made them virulent and killed the mice.
So, the correct answer is option A.

Note: Fredrick Griffith’s experiment with bacterium was the first one to reveal the transforming principle which he assumed as genetic bacteria and discovered that DNA acts as the carrier of genetic information.