Question

Write 1-2 paragraphs explanation of the mechanism of transformation uncovered by Oswald Avery.

Answer 1

Griffith proved that something was transferred from smooth strain to rough strain which conferred virulence to it.

Avery, Mc Leod and Mc Carty proved it to be DNA.

They isolated the filtrate and added different enzymes.

Protease, lipase, DNAase , RNAase and amylase. He found that mice died when DNAase was added

No transformation occured when DNAase was added which proved that DNA is a transforming principle.

They prepared cultures containing the heat-killed S strain and then removed lipids and carbohydrates from the solution
Next they treated the solutions with different digestive enzymes (DNase, RNase or protease) to destroy the targeted compound
Finally, they introduced living R strain cells to the culture to see which cultures would develop transformed S strain bacteria

Only in the culture treated with DNase did the S strain bacteria fail to grow (i.e. no DNA = no transformation)

This indicated that DNA was the genetic component that was being transferred between cells.