biology people and expiraments

Griffith

Griffith

“transformation”  when he mixed heat-killed remains of the pathogenic strain with living cells of the nonpathogenic strain, some of these living cells became pathogenic.

Avery, Mcleod and McCarty (1930s-40s)

• performed subsequent experiments in which they extracted and analyzed the “transforming principle”, which showed that it was DNA.

• Viruses that infect bacteria, bacteriophages, are widely used as tools by researchers in molecular genetics.

Erwin Chargaff

analyzed the base composition of DNA from a number of different organisms, and found that the amount of adenine bases (A) matched the amount of thymine (T). It wad the same for guanine and cytosine, which was Chargaff’s rule.

Maurice WIlkins and Rosalind Franklin

were using a technique called X-Ray crystallography to study molecular structure. They produced a picture of the DNA molecule

Hershey and Chase

proved that DNA is made of transformative material.

rosalind franklin

DNA was composed of two antiparallel sugar-phosphate backbones, with the nitrogenous bases paired in the molecule’s interior.

• The nitrogenous bases are paired in specific combinations: adenine with thymine, and cytosine with guanine.