Nucleic Acids and the Genetic Material Problem Set 1

Problem 7: Transformation

Frederick Griffith accidentally discovered transformation when attempting to develop a vaccine for pneumonia. He injected mice with samples from S-strain (virulent) and/or R-strain (nonvirulent) pneumococci bacteria (Streptococcus pneumoniae) . Which of the following results is NOT consistent with Griffith's experiments?
A injected S-strain; mouse dies.

B injected R-strain; mouse lives.

C injected heat-killed S-strain; mouse lives.

D injected mixture of heat-killed S-strain and live R-strain; mouse lives.

E injected mixture of heat-killed R-strain and live S-strain; mouse dies.

Griffith, 1928

  1. Mice injected with S strain pneumococcus die.

  2. Mice injected with R strain live.

  3. Extracts from S strain transform the R strain into virulent S strain.

  4. Observation gives a potential assay for the genetic material.

The Biology Project
University of Arizona
Thursday, October 3, 1996
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