Journal Entry• We often see diagrams and models of DNA in
electronic and print media. How do you think scientists determined the structure of DNA?
Introduction to DNA
• DNA: deoxyribonucleic acid
•http://www.khanacademy.org/science/biology/v/dna
History of DNA
• 1871 - Friedrich Miescher isolated nucleic acids from the nuclei of white blood cells.
• 1888 -Walter Sutton and Theodor Boveri suggested that the genetic material of the cell is contained in chromosomes (chromosomal theory of inheritance).
• Chromosome: strand of genes that carry hereditary information (DNA)
• Centromere joins two identical copies of DNA called sister chromatids
• Found in the nucleus of our cells
• 1910 -Phoebus Levene showed that DNA and RNA are distinct nucleic acids, but both are composed of long chains of nucleotides.
• 1928 - Frederick Griffith performed experiments indicating that DNA is probably the genetic material of the cell.
• 1952 -Alfred Hershey and Martha Chase clearly showed that DNA is the genetic material of the cell.
• 1952 - Edwin Chargaff demonstrated that the number of adenines always equals the numberof thymines, and the number of cytosines always equals the number of guanines.
• Rosalind Franklin and Maurice Wilkins used X-ray crystallography to show the helical structure of DNA.
DNA Model
• http://www.pbs.org/wnet/dna/dna_explorer/index2.html
• Quiz on these scientists Monday!• Matching format
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