Transcript Ch 12-1, Part 1 Griffith

Chapter 12-1
DNA
Part 1
I. Griffith and Transformation
(1928)
A. Griffith needed to know which
bacteria caused pneumonia so he
could to develop vaccine.
B. He isolated 2 strains of bacteria
1. Smooth/encapsulated bacteria
2. Rough/non-encapsulated bacteria
C. Experiment: He
isolated both strains
and injected them
into mice.
1. Smooth bacteriainjected into
mice mice die
2. Rough bacteriainjected into
mice mice live
IS THERE A WAY TO
KILL BACTERIA?
Which bacteria strain causes pneumonia
Smooth Bacteria
____________
Which bacteria strain that does not cause
pneumonia _______________
Rough Bacteria
3. Heat killed smooth bacteria- injected into
mice
mice live
4. Mixed heat killed smooth bacteria with rough
bacteria- injected into mice
mice die
X X
5. Conclusion: The rough
(harmless) strain of
bacteria had been
transformed into the
smooth (diseasecausing) strain.
A transformation
had occurred.
6. Griffith thought the
transforming factor
might be a gene.
Experiment 1
Experiment 2
Inject mouse with
Inject mouse with
rough
________bacteria
________bacteria
smooth
Experiment 3
Experiment 4
Inject mouse with
Inject mouse with
_______________
Heat killed smooth ________________
Heat killed smooth
bacteria
And ____________
rough
bacteria
Lives 
Mouse _________
Dies 
Lives  Mouse _________
Dies 
Mouse _________
Mouse _________