DNA Structure and Function Study Guide AP Biology 1. Match each scientist listed below with their contribution to the study of DNA. A. Frederick Griffith B. Hershey and Chase C. Rosalind Franklin D. Watson and Crick E. Erwin Chargaff Discovered that there were equal amounts of the nitrogen bases A T and C G in a human body cell; concluded that A paired with T and C paired with G. Did experiments with viruses to determine that DNA, not protein, is the genetic material of a cell. Did experiments with S and R strain pneumonia bacteria to determine that DNA is the genetic material of a cell Took x-ray crystallography images of a DNA molecule.

E. Erwin Chargaff >>  Discovered that there were equal amounts of the nitrogen bases A T and C G in a human body cell; concluded that A paired with T and C paired with G

B. Hershey and Chase>> Did experiments with viruses to determine that DNA, not protein, is the genetic material of a cell

A. Frederick Griffith>> Did experiments with S and R strain pneumonia bacteria to determine that DNA is the genetic material of a cell

C. Rosalind Franklin >> Took x-ray crystallography images of a DNA molecule.

Explanation:

Chargaff rules helped to determine the double helix structure of the Deoxyribonucleic acid (DNA), i.e., the genetic material of prokaryotic and eukaryotic organisms. Chargaff indicated that DNA from any species contains a 1:1 ratio of purine bases (Adenine and Guanine) and pyrimidine bases (Cytosine and Thymine). Hershey and Chase provided evidence that the DNA, instead of protein, is the hereditary material. Hershey and Chase used radioactive phosphorus-32 in order to label the DNA of specific bacteriophages (T2), and they discovered that the DNA was responsible to generate progeny inside infected bacteria (i.e., DNA was hereditary material). Frederick Griffith observed that DNA molecule was the transforming factor that could be transferred to innocuous Streptococcus pneumoniae bacteria in order to convert them into deadly bacteria. Finally, Rosalind Franklin obtained the first X-ray image that showed the diffraction pattern of a crystallized DNA molecule, which was used by Watson and Crick to propose that DNA had a double helix structure.

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