DNA as the Genetic Material

Key Concepts

• Griffith's Experiment: Discovered the "transforming principle."

• Avery-MacLeod-McCarty Experiment: Identified DNA as the "transforming principle."

• Hershey-Chase Experiment: Confirmed DNA is the genetic material using phages and radioactive labels.

• Properties of Genetic Material: Must be able to store information, replicate accurately, express information, and allow for variation.

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• Examples

• Transformation in Genetic Engineering: The principle discovered by Griffith is directly applied in modern genetic engineering, where foreign DNA can be introduced into bacteria to give them new traits (e.g., antibiotic resistance).

• Forensic Science: The stability and information storage capacity of DNA are why it is used so extensively in forensic science for identification from even small samples.

• Evolution: The capacity for mutation in DNA is the fundamental basis for natural selection and the diversity of life on Earth.

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• Flashcards

• Term: Griffith's Experiment

• Definition: Showed a "transforming principle" could transfer genetic traits between bacterial strains.

• Term: Avery-MacLeod-McCarty Experiment

• Definition: Identified DNA as the "transforming principle" by showing DNase prevented transformation.

• Term: Hershey-Chase Experiment

• Definition: Used radioactively labeled phages to definitively prove DNA, not protein, is the genetic material.

• Term: Properties of Genetic Material

• Definition: Information storage, accurate replication, information expression, and capacity for variation.

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• Memory Aids

• Griffith: Got the idea of a "transforming principle."

• Avery-MacLeod-McCarty: All Molecules Made of DNA. (They showed DNA was the molecule).

• Hershey-Chase: Helped Confirm DNA's role definitively using Hot Phosphorus (32P for DNA). Think of "P" for "Phosphate" (in DNA) and "S" for "Sulfur" (in protein).

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Examples & Applications

Memory Aids

Interactive tools to help you remember key concepts

Glossary