Question

In Griffiths experiment, the conversion of R-type to S-type of Diplococcus pneumonia when mixed with heat-killed S-type is called
A) Mutation
B) Transduction
C) Transfection
D) Transformation

Answer 1

Hint: Griffith's experiment, described in 1928 by Frederick Griffith, was the first to show that bacteria may transmit genetic data via a specified procedure.

Complete answer:
In Griffith's experiment, bacteria from the III-S strain were destroyed by heat and their remnants were mixed with bacteria from the II-R strain. While neither alone was harmful to the mice, the combination proved lethal. Griffith was also able to isolate live II-R and live III-S pneumococcus strains from the blood of these deceased mice. Griffith concluded that a "transforming principle" that was somehow part of the dead III-S strain bacteria "transformed" the type II-R into the lethal III-S strain. It is now know that Griffith saw the ‘transforming principle’ in the DNA of the III-s strain bacterium.

Hence, the correct answer here is transformation i.e, option ‘D’.

Note: Griffith discovered DNA from the III-s strain of bacteria. The DNA had survived the heating process and was picked up by the II-R strain bacterium, despite the fact that the bacteria had been destroyed. The genes that create the smooth protective polysaccharide capsule are found in the DNA of the III-S strain. With this gene, the former II-R strain bacteria were now immune to the host's immune system and could kill it.