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Ch. 11.1: Genes are made of DNA

Ch. 11.1: Genes are made of DNA. Objectives: Describe historic discoveries that lead to the understanding that DNA is responsible for heredity. Scientists: Griffith, Avery, Hershey & Chase Vocab.: virus, bacteriophage Bill Nye’s Greatest Discoveries:

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Ch. 11.1: Genes are made of DNA

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  1. Ch. 11.1: Genes are made of DNA Objectives: Describe historic discoveries that lead to the understanding that DNA is responsible for heredity Scientists: Griffith, Avery, Hershey & Chase Vocab.: virus, bacteriophage Bill Nye’s Greatest Discoveries: http://www.youtube.com/watch?v=vP_h08cT5jw http://www.youtube.com/watch?v=p9M5xJTs-zY&feature=related http://www.youtube.com/watch?v=x-0P_DIeHBs&feature=related

  2. 1928s • Result: Genetic material can be transformed! • What molecule controls genes: Protein or DNA? http://www.youtube.com/watch?v=9R2Zp7IHNZo http://www.youtube.com/watch?v=vQOdDGM5vSg&feature=related

  3. AVERY: Determines identity of “Transforming Factor” (Not Protein!) (enzyme that denatures proteins) (enzyme that denatures DNA)

  4. 1952: Experiments using BACTERIOPHAGE (virus that attacks bacteria) Virus: Nucleic acid inside a protein coat (no cells) Virus: injects its DNA into living organisms; viral DNA hijacks cells to make more viruses Radioactively label protein coat or DNA; ONLY radioactive DNA is INSIDE DAUGHTER CELLS. Hershey & Chase: Prove DNA = Genetic material http://www.youtube.com/watch?v=YG3d77SRWZI

  5. 11.2: Structure of DNA Objectives: • Identify the building blocks of DNA. • Describe DNA’s structure and the rules for base pairing in DNA. Vocab: Deoxyribonucleic acid (DNA), nucleotide, Nitrogenous base, pyrimidine, purine, double helix

  6. DNA: Deoxyribonucleic Acid DNA molecule: polymer made of thousands of nucleotides. Nucleotide: Building block (monomer) 5-C sugar: Deoxyribose Phosphate group Nitrogen base DNA structure: http://www.youtube.com/watch?v=ZGHkHMoyC5I Bill Nye: http://www.youtube.com/watch?v=V9BZ3zx8b8I&feature=related

  7. Bases • Types • 1. Pyrimidines: single ring • Thymine (T) • Cytosine (C) • 2. Purines: Double ring • Adenine (A) • Guanine (G) Base Pairing Rules: A = T; C = G (Chargaff discovery). H-bonds attract pairs together.

  8. DNA Structure Backbone (Sides of “Ladder”) Sugar Phosphates Rungs of Ladder Complementary Bases DNA Function • Store genetic info. • Self-duplication • Expression of genes (inherited traits) DNA’s major function = CODE FOR PROTEINS

  9. Double Helix • Rosalind Franklin & Maurice Wilkins (1950s) • DNA = Helix • X-ray crystallography to “see” structure • James Watson & Francis Crick (1950s) • “Crack Code” …determine specifics of DNA structure. • DOUBLE HELIX

  10. Watson & Crick Double Helix • 2 chains of nucleotides • 2 strands are anti-parallel • Backbone: sugar + phosphate • Base pairs = rungs

  11. Prokaryotes Circular Very small 1 chromo. per cell Some enzymes & proteins are associated w/ DNA Not housed in nucleus Eukaryotes Linear Fairly long Several per. Cell Nucleosome: Loops of DNA wrapped around histone proteins In nucleus DNA & Chromosomes

  12. DNA is coiled around protein histones; those coils are coiled into chromosomes. DNA Organization

  13. 11.3: DNA Replication Objectives: • Explain how the template mechanism is important in DNA replication. • Describe the process of DNA replication. Vocab: DNA Replication, DNA polymerase, semi-conservative

  14. Template Mechanism • DNA replication is SEMI-CONSERVATIVE • New copies of DNA contain: • 1 original strand • 1 new strand Each strand serves as a TEMPLATE to make a complementary copy (due to base-pairing rules)

  15. DNA Replication:Making copies of DNA Enzymes Involved: Helicase: unwinds double helix DNA Polymerase: Attaches new nucleotides; can only add to the 3’Carbon Ligase: join fragmented copies on “lagging” strand.

  16. Leading Strand: continuous growingLagging Strand: Fragmented; ligase joinsNEW STRANDS GROW in 5’ --> 3’ direction! http://www.youtube.com/watch?v=AGUuX4PGlCc&feature=related http://www.youtube.com/watch?v=4jtmOZaIvS0

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