oswald avery

Transformation Principle

The concept that DNA is the material responsible for genetic transformation in bacteria.

Oswald Avery

A Canadian-born American bacteriologist who discovered the transforming principle was DNA.

Fredrick Griffith

A scientist whose work with bacterial strains led to the discovery of the transformation principle.

Virulent

A strain of bacteria that is capable of causing disease.

Nonvirulent

A strain of bacteria that does not cause disease.

Avery-MacLeod-McCarty Experiment

An experiment that demonstrated DNA is the transforming principle.

Heat-killed S Cells

Bacterial cells that were killed by heat but used in transformation experiments to show the transfer of DNA.

DNAse

An enzyme that breaks down DNA, used in the transformation experiments to confirm DNA as the transforming principle.

Hypothesis

A proposed explanation based on limited evidence as a starting point for further investigation, in this case, that DNA is the transforming principle.

Inheritance

The transmission of genetic characteristics from one generation to another.

Polysaccharide Capsule

A protective layer surrounding some bacteria that makes them virulent.