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KCET · BIOLOGY · STD 12 - 5. Molecular Basis of Inheritance

The result of which of the following reaction experiments carried out by Avery et.al. on Streptococcus pneumoniae has proved conclusively that DNA is the genetic material?

  1. A Live 'R' strain + DNA from 'S' strain + RNAase
  2. B Live 'R' strain + DNA from 'S' strain + DNAase
  3. C Live 'R' strain + Denatured DNA of 'S' strain + protease
  4. D Heat killed 'R' strain + DNA from 'S' strain + DNAase
Verified Solution

Answer & Solution

Correct Answer

(B) Live 'R' strain + DNA from 'S' strain + DNAase

Step-by-step Solution

Detailed explanation

(B) Live 'R' strain + DNA from 'S' strain + DNAase,
R-strain is rough and harmless, while S-strain is smooth and virulent form of Streptococcus pneumoniae. In their experiment, Avery et al., found out that only when DNA from S-type get converted to S- type strain. This transformation of R into S-type bacteria is added to a culture of R - type bacteria, R-type get converted to S-type strain.