Question Bank [2022] — BIOLOGY STD 12 Science — Question
Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYQuestion Bank [2022]2 Marks
Question
Explain Avery, McCarty, and MacLeod’s experiment in detail.
✓
Answer
Avery, Macleod, and McCarty (1944) purified DNA, RNA, proteins (enzymes), and other materials from heat-killed S-type and mixed them with R-type to see which ones could transform living R-types to S-types.
Only those mixed with DNA were transformed into S-type bacteria.
They also discovered that protein-digesting enzymes (proteases) and RNA-digesting enzymes (RNases) did not affect transformation. This indicated the transforming substance was neither a protein nor RNA.
DNA digested with DNase inhibited transformation, suggesting that DNA caused the transformation.
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