Fred Griffiths' Experiment

Question 1

What they worked with?

Answer 1

• Worked with different strains of the bacterium Diplococcus pneumoniac
• Some virulent strains (cause diseases) others non-virulent
• Virulent - slimy capsule

Question 2

Injected virulent S-strain=

Answer 2

mice died

Question 3

Injected non-virulent R-strain=

Answer 3

Mice survived

Question 4

Killed some s-strain by heating them up…

Answer 4

Mice survived

Question 5

Mixed dead S-strain with living R-strain…

Answer 5

Mice died

Question 6

Capsule caused disease, injecting it alone =

Answer 6

•no affect

Question 7

Somehow dead S-strain had ‘transformed’ the R-strain into virulent S-strain…

Answer 7

No explanation

Question 8

Why did the mouse with heat killed S-strain mixed with R-strain die?

Answer 8

DNA from the S-strain renatured, went in the R strain and it reproduces the S-strain protein live