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DNA "The Blueprint of Life"
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Hershey-Chase Experiment
1952 experiment that determined that DNA was the genetic material. Alfred Hershey ( ) and Martha Chase ( ) showed that the DNA, not the protein, of the phage virus contains the phage genes. After a phage particle attaches to a bacterium, its DNA enters through a tiny hole while its protein coat remains outside. Key to the success of the experiment was showing that viral infection was unaffected by violent agitation in a kitchen blender (a Waring Blendor) which removed the empty viral protein shells from the bacterial surface. The Hershey-Chase experiment became known as the "blender experiment."
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DNA stands for... DeoxyriboNucleic Acid
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DNA FACTS Discovery of DNA and Nobel Prize to James Watson and Francis Crick Described specifics of the double helix structure
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DNA FACTS Francis and Crick built on the research of:
Rosalind Franklin determined double-helix shape using x-ray crystallography Erwin Chargraff determined that the number of pyrimidines= purines (complementary base pairing)
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DNA Facts: (cont’d) codes for your genes (traits)
made of repeating subunits called nucleotides two anti-parallel strands
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What is a nucleotide? Has three parts: PHOSPHATE DEOXYRIBOSE (sugar)
BASE : Purines: (hex plus pent structure) Adenine, Guanine Pyrimidines: (hex structure) Cytosine, Thymine, Uracil
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Base-Pair Rule Adenine <==> Thymine Guanine <==> Cytosine
The sides of the DNA ladder are phosphate & sugar held together by hydrogen bonds
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Base Pair Rule One side: A T A T C A T G C G G G Other side:
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How the Code Works The combination of A,T,G,C determines what traits you might have..... C A T C A T = purple hair T A C T A C = yellow hair
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Think of the bases of DNA like letters.
Letters form words.... Words form sentences.... *endless combinations
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Let's Review What We Know About DNA
1. DNA stands for: De _____ ribo ______ acid 2. What is the shape of DNA? _______________ 3. Who established the structure of DNA? ____________ 4. Adenine always pairs with _______________ 5. The sides of the DNA ladder are deoxyribose and _____ 6. Guanine always pairs with _____________ 7. What is the complimentary sequence: A A T G C A 8. The two sides of DNA are held together by _______ bonds. 9. DNA is composed of repeating subunits called ______________________ 10. What are the 4 bases that make up the rungs of the DNA ladder? _______________________________________
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DNA REPLICATION the process by which DNA makes a copy of itself (cell division) SEMI-CONSERVATIVE - half of the old strand is saved
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RNA - the messenger *single strand *ribose sugar *contains no thymine, uracil instead *follows base pair rule DNA: A T A G C G RNA:
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RNA carries the "message" to the ribosomes, where proteins are made
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DNA --> RNA --> Protein
Proteins are the building blocks of the organism (traits)
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Transcription - process where RNA is made from DNA
Translation - process where proteins are made from RNA
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