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Structure and Function

Structure and Function. 1) Choose an item. Explain - How does the structure of this item support its function ?. 2) What should be the functions of DNA ? What would you expect this molecule to do ?. Journal: Anticipation Guide handout. Answer on your own.

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Structure and Function

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  1. Structure and Function 1) Choose an item. Explain - How does the structure of this item support its function? 2) What should be the functions of DNA? What would you expect this molecule to do?

  2. Journal: Anticipation Guide handout. • Answer on your own. • Share afterwards with your neighbor • Turn it in. • Will be answered again, later in the unit.

  3. James Watson and Francis Crick 1953.

  4. 1940’s: DNA is the genetic material * A chemical from dead harmful bacteria can transform nearby ‘naive’ cells to become harmful. * Not a protein: No Sulfur, lots of phosphate, breaking down proteins does not prevent it action.

  5. The Structure of DNA was discovered based on it’s predicted functions as the genetic material: 1. DNA contains specific genetic information. 2. DNA carries information to the next generation: by accurate replicating.

  6. Early information about DNA structure: • Monomers: Nucleotides • A, C, G, T • 2) Chargaff’s Rules: The amount of each nucleotide show a universal behavior: A=T, C=G. • 3) Three dimensional data: Twisted Ladder

  7. DNA is a chain of nucleotides: Pyrimidines Purines Thymine Guanine Adenine Cytosine

  8. James Watson and Francis Crick 1953.

  9. Try and Figure it out! Use the materials you have in hand and the clues from ‘previous knowledge’ to build a DNA model.

  10. Powernotes: DNA Fill in the handouts, then color the back side, according to directions.

  11. Considering the two models of DNA. A. Compare: Which parts are similar? Which parts are different? (ignore ribbon color) B. Where in the moleculemight the specific information be? C. How might DNA replicate? 07.20.11 Journal 2

  12. View the animation of replication. Describe what you see in at least three bullets – You can add a drawing for support, but this is not mandatory. 07.21.11 J3

  13. Detailed but clear! Animation of Replication Lewport NOBEL PRIZE RePLICATION Replication – Animation: Fast DNA Replication - Calsszone

  14. Building DNA from models: • Pipes: pick up • 20 black parts,10 connectors • 20 white pipes • 8 blue, yellow • 10 orange , green • Beads: - 20 red, 20 white • 10 orange, green, blue, yellow, • 10 connectors

  15. Copy the following DNA strand: A G G T C C T A T G -- -- -- -- -- -- -- -- -- -- A. What would be the order of nucleotides in the opposite strand (blanks)? B. How many nucleotides are in each strand? C. How many phosphates and sugars are on each side of this DNA? 07.21.11 J4

  16. Animation of Replication Lewport Movie of DNA Replication (DNAi) * Speed of replication: ~50 base-pairs / second. * Human DNA contains about 150x106 (150 million) base-pairs. How long would it take to replicate? * It actually takes about an hour. Why?

  17. Animation

  18. DNA is a chain of nucleotides: Pyrimidines Purines Thymine Guanine Adenine Cytosine nucleotide Phosphate group Deoxyribose

  19. Adenosine Tri Phosphate Adenine (ATP) Phosphates Ribose (sugar) A-Nucleotide!

  20. 2. Chargaff rules: In all organisms, A=T C=G Source of DNA A T G C Streptococcus 29.8 31.6 20.5 18.0 Yeast 31.3 32.9 18.7 17.1 Herring 27.8 27.5 22.2 22.6 Human 30.9 29.4 19.9 19.8

  21. 3. Rosaline Franklin, X-Ray Crystallography: DNA is made like a double twisted ladder

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