Classical Experiment Flashcards
What is Classical Experiment ?
DNA harbours genetic information .
First Experimental that DNA is the genetic material.
What year did this get carried out ?
1920s/1940s
What was the purpose ?
Showed that adding purified DNA to a bacterium changed the bacterium’s properties and this change was passed to a generation
What is the Smooth strain of bacterium ?
Appears small and causes death when injected into a mice.
Forms colonies which are rounded .
Smooth was due to polysaccharide or sugar base , coat protected by the bacteria when injected in the mouse.
Developed pneumonia and died .
What about the R strain of bacterium ?
R bacteria formed colonies or clumps of related bacteria Rough appearance.
What happens when the harmless R bacteria was combined with the heat killed S bacteria injected in the mouse ?
Mouse developed pneumonia and died but took a blood sample and contained S bacteria living .
Performing the experiment ?
Set out to identify transforming principle.
Washing away ,separating out or enzymatic destroying cellular components .
Obtain smaller amounts of highly purified transforming principle through analysed through other tests to determine identity .
Results
- Protein
+ DNA
Protein and RNA degrading enzymes had little effect on transforming principle enzymes degrade DNA eliminate the transforming activity.
Identification DNA as the genetic material .
Conclusion :
Molecules that carry heritable information are present in S strain cells.
The molecules that carries heritable information is DNA.
What does Bacteria Normally have ?
1 Copy of most genetic information (haploid)
Eukaryotes ( Diploids )
2 redundant copies .
