The Griffith Experiment quiz Flashcards
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What was the main conclusion of Frederick Griffith's experiment?
Griffith concluded that bacteria could transform genetic material, specifically that the R strain could uptake DNA from the heat-killed S strain, resulting in a genotypic and phenotypic change.
What are the three types of bacteria used in Griffith's experiment?
The three types are the smooth (S) strain, the rough (R) strain, and the heat-killed S strain.
Why is the S strain of bacteria lethal in Griffith's experiment?
The S strain is lethal because it has a smooth surface with a capsule that protects it from the host's immune system.
What happens to mice injected with the R strain of bacteria?
Mice injected with the R strain remain alive because the R strain is non-lethal.
What was the surprising result of combining the R strain and heat-killed S strain in Griffith's experiment?
The combination of the R strain and heat-killed S strain killed the mice, and living S strain bacteria were extracted from the dead mice.
What did Griffith's experiment demonstrate about the genetic material?
It demonstrated that genetic material could be transferred between bacteria, leading to transformation.
Who identified the transforming substance in Griffith's experiment as DNA?
Oswald Avery, Colin MacLeod, and Maclyn McCarty identified the transforming substance as DNA.
Why were many scientists skeptical that DNA was the genetic material?
Many scientists were skeptical because very little was known about DNA at the time, and proteins were considered a better candidate for genetic material.
What is meant by 'transformation' in the context of Griffith's experiment?
Transformation refers to the uptake of external DNA by bacteria, resulting in a genotypic and phenotypic change.
What did Griffith inject into mice in his first experiment, and what was the result?
Griffith injected the lethal S strain into mice, resulting in the death of the mice.
What was the result when Griffith injected mice with heat-killed S strain bacteria?
The mice remained alive because the heat-killed S strain bacteria were not capable of reproducing.
What did Griffith observe when he injected mice with a combination of R strain and heat-killed S strain?
He observed that the mice died, and living S strain bacteria were extracted from the dead mice.
What did Griffith's experiment suggest about the nature of genetic material?
It suggested that genetic material could be transferred between bacteria, leading to transformation and changes in phenotype.
What is the significance of the capsule in the S strain bacteria?
The capsule in the S strain bacteria makes it lethal by protecting it from the host's immune system.
What did Griffith's experiment reveal about the ability of bacteria to uptake external DNA?
It revealed that bacteria have the ability to uptake external DNA, leading to transformation and changes in their genetic and phenotypic characteristics.