Question

What is the transforming principle in Griffith's experiment?

• A. A protein that transfers genetic information.
• B. A polysaccharide coat present in S-strain bacteria.
• C. A substance that can transfer genetic material from one bacterium to another.
• D. A lipid molecule responsible for bacterial transformation.

Hint:

Griffith's experiment demonstrated the concept of transformation in bacteria, providing evidence for a hereditary molecule. This was later confirmed to be DNA by Avery, MacLeod, and McCarty.

Answer 1

The Correct Option is C

The correct Option is : 3

Step 1: Griffith's experiment overview. 
Frederick Griffith, in 1928, conducted experiments with two strains of Streptococcus pneumoniae

S-strain: Virulent, with a polysaccharide coat, causing disease. 

R-strain: Non-virulent, lacking the polysaccharide coat. 

Step 2: Discovery of the transforming principle. 
Griffith observed that heat-killed S-strain bacteria, when mixed with live R-strain bacteria, could transform the R-strain into the virulent S-strain. This transformation indicated the presence of a "transforming principle" capable of transferring genetic information. 

Step 3: Explanation of options. 
Option (A): Incorrect. Proteins were later ruled out as the transforming principle by experiments conducted by Avery, MacLeod, and McCarty. 

Option (B): Incorrect. The polysaccharide coat is not responsible for transformation but is a characteristic of the S-strain. 

Option (C): Correct. The transforming principle is a substance (later identified as DNA) that can transfer genetic material from one bacterium to another. 

Option (D): Incorrect. Lipids are not involved in bacterial transformation. 

Step 4: Conclusion. 
The transforming principle in Griffith's experiment was identified as a substance capable of transferring genetic material, which laid the foundation for the identification of DNA as the genetic material.