Avery,MacLeod,and McCarty (1944)demonstrated that DNA was the genetic material by treating heat-killed Streptococcus pneumoniae S (smooth)strain with DNase,thereby preventing transfer of the "transforming substance" from the killed S strain to the live R (rough)strain when the two were mixed together and injected into mice.Another way that one could demonstrate transformation in bacteria would be to extract DNA from
A)an R strain and mix it with cells of an S strain.
B)both S and R strains and mix it to allow recombination to take place.
C)an ampicillin-sensitive strain and mix it with cells of an ampicillin-resistant strain.
D)an S strain and mix it with cells of an R strain.
E)None of the above are correct.

Question

Quizplus · Accepted Answer

The correct answer is to extract DNA from an S strain and mix it with cells of an R strain. This would potentially allow the R strain to take up the DNA from the S strain and undergo transformation, possibly converting to an S phenotype if the DNA includes genes responsible for the S strain's smooth capsule. This is analogous to the original experiment by Avery, MacLeod, and McCarty, which demonstrated that DNA is the material responsible for genetic transformation.

Avery,MacLeod,and McCarty (1944)demonstrated That DNA Was the Genetic Material by Treating