Ch. 10 DNA (Deoxyribonucleic acid) Mr. D

A. People and History 1. Frederick Griffith Demonstrated the transformation and transfer of genetic material from one organism to another.

2. Oswald Avery Tested whether Griffith’s transforming agent was protein, RNA, or DNA. Found that DNA was the transforming material.

3. Hershey and Chase Martha Chase and Alfred Hershey tested whether DNA or protein was the hereditary material viruses transfer when they enter a bacteria. They found it to be DNA.

4. James Watson and Francis Crick Discovered the structure of DNA in 1953. Found to be a double helix (twisted ladder) Confirmed by X-ray crystallization done by Rosalind Franklin and Maurice Wilkins

B. DNA is a nucleotide 3 parts 5-carbon sugar Phosphate 1 of 4 nitrogen bases Adenine (A) Guanine (G) Cytosine (C) Thymine (T)

Bases Adenine and guanine are purines Cytosine and thymine are pyrimidines C. Base Pairing Erwin Chargaff found that the number of adenine bases equals the number of thymine bases and the number of guanine equals the number of cytosine (Chargaff’s Rules)

The phenomenon of Chargaff’s rules shows that DNA has complimentary base pairs. Base pairs are held together by hydrogen bonds. Match the following DNA chain with it’s complimentary base chain: Strand 1->T A C G G C T A A T C G A Strand 2->