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DNA: The Genetic Material. Identifying the Genetic Material. Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944). Hershey & Chase used the bacteriophage T2 and radioactive labels to show that virus genes are made of DNA, not protein (1952).
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Identifying the Genetic Material • Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944)
Hershey & Chase used the bacteriophage T2 and radioactive labels to show that virus genes are made of DNA, not protein (1952)
DNA stores information that tells cells which proteins to make and when to make them
The Structure of DNA • Discovered by Watson & Crick in 1953 & received Nobel Prize in 1962 along with Maurice Wilkins
DNA Polymer : Nucleotide Monomer • Each Nucleotide has 3 parts: • 1) 5 carbon sugar Deoxyribose • 2) Phosphate group PO4 • 3) Nitrogen Base
DNA forms a spiral ladder Double Helix • Double helix is held together by weak Hydrogen bonds • Erwin Chargaff Discovery Chargaff’s Rule A=T, G=C
DNA Replication • Phase of Cell Cycle? Why replicate? • Step 1: DNA Helicase unzips DNA by breaking weak Hydrogen bonds. • Step 2: DNA polymerase adds nucleotides to exposed nitrogen bases. • Step 3: Two DNA molecules form that are identical to original.
DNA is referred to as “Semi-conservative”, Each DNA molecule 1 template & 1 new strand • DNA polymerase proofreads DNA during its replication so that very few errors occur
500/sec bacteria • 50/sec human
