1. B ELL R INGER 9-17-15 1. How is diffusion different from an ion pump? a. Diffusion takes place due to osmotic pressure b. Diffusion requires the cell to use energy for the transfer of molecules c. Diffusion does not transfer all of the ions across the cell membrane d. Diffusion transfers molecules from an area of high to low concentration 2. Most animal cell membranes have proteins that pump ________ ions out of the cell and potassium ions into the cell. a. Calcium b. Carbon c. Magnesium d. Sodium 3. Living cells use _______________ as their main source of energy. a. Carbohydrates b. Cellulose c. Lipids d. Proteins

2. A GENDA Standard Notes – A History Lesson Timeline Closing – Crossword Puzzle

3. S TANDARD SB2. Students will analyze how biological traits are passed on to successive generations. Distinguish between DNA and RNA. Explain the role of DNA in storing and transmitting cellular information

4. D ISCOVERING DNA 3 major experiments that led to the conclusion that DNA is the genetic material in cells: Griffith’s Discovery of Transformation Avery’s Experiments with Nucleic Acids Hershey-Chase Experiment

5. G RIFFITH ’ S D ISCOVERY OF T RANSFORMATION When: 1928 Who: Frederick Griffith What: He was working with two related strains of bacteria One strain, S, causes pneumonia and is covered by a capsule made of polysaccharides. The other strain, R, has no capsule and doesn’t cause pneumonia. What caused the pneumonia? The bacteria or the capsule?

6. H OW Griffith used mice to test the bacteria. S bacteria caused pneumonia. And, R bacteria is completely harmless.

7. H OW He decided to use heat to kill the bacteria (the capsule remained). When the mice were injected with the heat killed S strain they did not get sick and die. When they were injected with heat killed S strain and live R strain they got sick and died, and live S strain was withdrawn from the dead mice Conclusion: transformation – a change in the genotype that is caused when cells take up foreign material. Huh? The R strain that was not lethal took up foreign material from the S strain and transformed into the lethal S strain

8. W HAT CAN WE LEARN FROM G RIFFITH ’ S E XPERIMENTS ? Genetic material can be transferred between cells. Still, no one knew that this genetic material was DNA. (That’ll come later.)

9. A VERY ’ S E XPERIMENTS WITH N UCLEIC A CIDS When: 1940s Who: Oswald Avery What: He wanted to figure out if the transforming agent in Griffith’s experiment was protein, RNA, or, DNA.

10. H OW In trying to determine if the transforming agent was DNA, RNA, or protein Avery used enzymes to destroy each of these molecules in heat-killed S bacteria. S bacteria that were missing protein and RNA were able to transform R cells into S cells. S bacteria without DNA did not transform R cells.

11. W HAT CAN WE LEARN FROM A VERY ’ S EXPERIMENTS ? DNA is responsible for transformation in bacteria. No idea what it looks like though!

12. H ERSHEY -C HASE E XPERIMENT When: 1952 Who: Alfred Hershey and Martha Chase What: Wanted to determine how DNA affected other cells.

13. H OW Studied bacteriophages (viruses that infect bacterial cells and cause the cells to produce viruses) They knew that protein has sulfur but not phosphorous and DNA has phosphorous but not sulfur. http://highered.mcgraw- hill.com/olc/dl/120076/bio21.swf

14. W HAT CAN WE LEARN FROM THE H ERSHEY -C HASE E XPERIMENT ? DNA is the hereditary material.

15. D ISCOVERING DNA’ S S TRUCTURE How did Watson and Crick figure out that DNA has a double helical structure? They used information from experiments by Chargraff, Wilkins, and Franklin.

16. C HARGRAFF ’ S O BSERVATIONS When: 1950 Who: Erwin Chargraff What: For each organism he studied: Amount of A=T Amount of G=C

17. F RANKLIN AND W ILKINS – P HOTOGRAPHS OF DNA When: 1952 Who: Rosalind Franklin and Maurice Wilkins What: Developed high-quality x-ray diffraction images of DNA The images suggested that a DNA molecule resembled a tightly coiled helix made of two chains of nucleotides.

18. W ATSON & C RICK When: 1953 Who: James Watson and Francis Crick What: Set out to physically build a 3D model of DNA Took into account Chargraff’s data and Franklin’s x-ray diffraction studies Also used their knowledge of chemical bonding

19. H OW Used paper models of the bases to figure out the base pairs of pyrimidines with purines. Made a 3D model of a DNA double helix using tin, wire, and other materials.

20. T IMELINE Use the pictures, dates, and names provided to create an accurate timeline. Be sure to include a summary of the experiments and conclusions

21. Griffith Avery Chargraff Franklin