Intro to Molecular Biology the study of DNA, RNA and Proteins

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Intro to Molecular Biology the study ofDNA,
RNA and Proteins
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A Brief History

• 1860s Mendel factors
• 1920s Chromosomes discovered
• Chromosomes composed of DNA and protein
• Griffith Bacteria Transformation
• Hershey Chase - discover DNA via bacteriophage.
  
• Chargaff
• Base pairing rule (C-G, A-T)
• Ratio of bases is species specific

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A Brief History

• Watson Crick structure of DNA
• Meselson Stahl - DNA replication is
  semiconservative.
• Beadle and Tatum - One gene one
  enzyme/polypeptide

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Nucleotides

• Nucleotides Nitrogenous base 5C sugar P

• Pentoses
• 5 carbon sugars
• ribose
• deoxyribose (1 less O atom)
• the pentose forms the central group of the
  nucleotide

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Nitrogenous Bases

• Pyrimidines
• (single ring bases)
• Cytosine
• Uracil
• Thymine
• (CUT a piece of PY)
• Purines
• (double ring bases)
• Adenine
• Guanine

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• Pentose is central molecule
• Nitrogenous base bonds to C1 by dehydration
  synthesis
• P group bonds to C5 by dehydration synthesis

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Nucleic Acids

• chains of nucleotides
• 2 types
• DNA made of DNA nucleotides (A-G, C-T)
  
• RNA made of RNA nucleotides (A-G, C-U)

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Replication

• DNA making new DNA

Step 1 Unwinding DNAStep 2 Unzipping DNAStep
3 Copying the DNA strandsStep 4 Sewing the
Fragments togetherStep 5 The 2 DNAs
separateStep 6 Proofreading Excision Repair