15 Questions
What is one of the criteria that scientists must follow when designing their experiments?
The experiment must be designed to answer a specific question
What type of data must a scientific experiment use?
Objective data
What is an essential component that a house must have, analogous to a requirement in scientific experiments?
Roof
Why is it important for scientists to follow certain rules when designing their experiments?
To ensure the value of their work within the scientific community
What is the primary purpose of a scientific experiment?
To provide objective results
What were Oswald Avery's objective results for the experiment?
A series of 'yes' or 'no' answers to the question, 'Did transformation occur in the absence of this factor.'
How did Avery confirm that DNA was the transforming principle?
Destroyed DNA with deoxyribonuclease and observed the absence of transformation.
What did Avery's experiment demonstrate about the transforming principle?
DNA was the source of genetic information.
How did Avery rule out the presence of RNA in the transforming principle?
Destroyed RNA with a ribonuclease enzyme and observed the absence of transformation.
What did Avery observe to determine whether transformation occurred?
Whether the R bacteria changed into S bacteria.
What did Frederick Griffith conclude from his experiment with pneumococcus bacteria?
A transforming principle was responsible for the change in the R bacteria
What did Oswald Avery and his colleagues discover to be the transforming principle?
Nucleic acids
What did Avery rule out as the transforming principle before identifying nucleic acids?
Proteins
What was the outcome of mixing live R cells with lysate from dead S cells in Avery's experiment?
The mixture yielded live S cells
What did Griffith observe when he mixed living R cells with dead S cells?
The mice injected with the mixture died
Study Notes
The Griffith Experiment: Discovering the Transforming Principle
- Frederick Griffith studied two strains of pneumococcus bacteria: S (smooth) and R (rough)
- Mice injected with S bacteria died, while those injected with R bacteria survived
- Griffith discovered that mixing living R cells with dead S cells caused the mice to die
- Griffith concluded that a transforming principle was responsible for the change in the R bacteria
- Oswald Avery continued Griffith's work to identify the transforming principle
- Avery's list of candidates for the transforming principle included the sugar coat, proteins, and nucleic acids
- Avery designed an experiment to test each factor separately and control for multiple variables
- He mixed live R cells with lysate from dead S cells and found that the mixture yielded live S cells
- Avery then tested whether the sugar coat or proteins were the transforming principle, but both were ruled out
- Nucleic acids in the lysate were isolated and found to contain the transforming principle
- Avery and his colleagues precipitated the nucleic acids, mixed them with water, and tested them for the transforming ability
- The nucleic acids were confirmed to be the transforming principle, leading to the discovery that DNA is the genetic molecule
Test your knowledge of the Griffith Experiment and the discovery of the transforming principle with this quiz. Learn about Frederick Griffith's groundbreaking research on pneumococcus bacteria and how Oswald Avery continued the work to identify DNA as the genetic molecule.
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