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Freddrick Griffith
Freddrick Griffith- 1928
Known as Griffith's Experiment, the first widely accepted
demonstrations of bacterial transformation, whereby a bacterium
distinctly changes it's form and function. He did this by testing
cases of lobar pneumonia could transform from one strain into a
different strain. This is connected to Oswald Avery discovered that
these strands were DNA and is what makes up genes and chromosomes. -
Oswald Avery
Discovered that DNA is the material of which genes and chromosomes are
made of. Here is a exact explanation of the experiment "Techniques
were available to remove various organic compounds from bacteria, and
if the remaining organic compounds were still able to cause R strain
bacteria to transform then the substances removed could not be the
carrier of genes. S strain bacteria first had the large cellular
structures removed. Then they were treated with protease enzymes,
which removed the protein -
Ewrin Chargaff
Erwin Chargoff was credited for two rules. The first rule
proposed the number of Cytosine bases there will be guanine bases and
Thymine biases will be the same as adenine bases. The second rule said
that the number of the A and T bases and G and C bases the different
numbers of the create more diversity. -
Rosland Franklin
Rosland Franklin studied the DNA molecule by a method called
X-ray diffraction. -
Alfred Hershey and Martha Chase
Alfred Hershey and Martha Chase discovered that only DNA is needed for
viral replication. Using radioactive isotopes 35S to track protein and
32P to track DNA, they show that progeny T2 bacteriophage isolated
from lysed bacterial cells have the labeled nucleic acid. Further,
most of the labeled protein doesn’t enter the cells but remains
attached to the bacterial cell membrane. -
Watson and Crick
Watson and Crick made the first DNA double helix model of DNA structure.
