GRIFFITH 'S TRANSFORMATION: His experiment was involving different mice and four samples of bacteria. He injected mice with heat-killed, disease-causing, harmless, and a mixture of heat-killed and harmless bacteria. He found that heat-killed bacteria and harmless bacteria didn't kill the mice, but together they caused fatal pneumonia. He concluded the process of transformation, because one type of bacteria (harmless) was changed permanently into another (disease). So he inferred that genetic information could be transferred from one bacterial strain to another, and that disease was inherited by the offspring of the transformed bacteria, so the transforming factor had to be a gene.  |
HERSHEY-CHASE EXPERIMENT: This experiment used different radioactive markers to label the DNA and proteins of bacteriophages. They found that bacteriophages injected only DNA, not proteins, into bacterial cells. Their experiment convinced many scientists that DNA was the genetic material found in genes, in all living cells, and not just in viruses and bacteria.  |
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MILLER-UREY EXPERIMENT: 1. Water is heated creating water vapor. 2. Methane, ammonia, and hydrogen are mixed and added to the water vapor. 3. The swirling gases are shot with sparks of electricity. 4. Droplets form, after cold water cools the chamber. 5. A week of sitting shows liquid is collected that has amino acids and other organic compounds. This experiment how shows mixtures of the organic compounds are necessary for life and that life could have arisen from simpler compounds on Earth, such as with DNA.  |
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