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DNA: The Genetic Material
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Identifying the Genetic Material Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944) Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944)
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Hershey & Chase used the bacteriophage T2 and radioactive labels to show that virus genes are made of DNA, not protein (1952) 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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DNA stores information that tells cells which proteins to make and when to make them DNA stores information that tells cells which proteins to make and when to make them
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The Structure of DNA Discovered by Watson & Crick in 1953 & received Nobel Prize in 1962 along with Maurice Wilkins Discovered by Watson & Crick in 1953 & received Nobel Prize in 1962 along with Maurice Wilkins http://www.youtube.com/watch?v =sf0YXnAFBs8&feature=autoplay& list=PL4900A106005340D0&lf=res ults_video&playnext=2
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DNA Polymer : Nucleotide Monomer DNA Polymer : Nucleotide Monomer Each Nucleotide has 3 parts: Each Nucleotide has 3 parts: 1) 5 carbon sugar Deoxyribose 1) 5 carbon sugar Deoxyribose 2) Phosphate group PO 4 2) Phosphate group PO 4 3) Nitrogen Base 3) Nitrogen Base
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Nitrogen Bases Purines Adenine Guanine Pyrimidines Thymine Cytosine
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DNA forms a spiral ladder Double Helix DNA forms a spiral ladder Double Helix Double helix is held together by weak Hydrogen bonds Double helix is held together by weak Hydrogen bonds Erwin Chargaff Discovery Chargaff’s Rule A=T, G=C Erwin Chargaff Discovery Chargaff’s Rule A=T, G=C ATGC Human30301919 Plant27272222 Virus21222827
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DNA Replication Phase of Cell Cycle? Why replicate? Phase of Cell Cycle? Why replicate? Step 1: DNA Helicase unzips DNA by breaking weak Hydrogen bonds. Step 1: DNA Helicase unzips DNA by breaking weak Hydrogen bonds. Step 2: DNA polymerase adds nucleotides to exposed nitrogen bases. Step 2: DNA polymerase adds nucleotides to exposed nitrogen bases. Step 3: Two DNA molecules form that are identical to original. Step 3: Two DNA molecules form that are identical to original.
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DNA is referred to as “Semi-conservative”, Each DNA molecule 1 template & 1 new strand 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 DNA polymerase proofreads DNA during its replication so that very few errors occur http://www.youtube.com/ watch?v=zdDkiRw1PdU
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500/sec bacteria 500/sec bacteria 50/sec human 50/sec human
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Eukaryotes Eukaryotes
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http://www.bing.com/videos/search?q=d na+replication+animation&mid=E308470 BDBE4EA7925E3E308470BDBE4EA7925E 3&view=detail&FORM=VIRE3&adlt=strict
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http://student.ccbcmd.edu/biotutorials/ dna/lag.html
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