1. April 27, 2010 Ms. Simon Regents Biology Introduction to Genetics

2. Do Now: 1) Identify some functions of proteins Muscle, enzymes catalyze reactions, channels, 2) What does DNA stand for? Deoxyribose nucleic acid 3) Why is DNA important? Determines our traits “Hereditary material”

3. AIM: Does our hereditary material come from DNA or proteins?

4. Meischer (1869) Treated pus (white blood cells) with pepsin enzyme breaks down proteins (protease) Isolated the nuclei, precipitate is formed (DNA) nitrogen and phosphorous found in nuclein= material of the nucleus

5. Characteristics of hereditary material (DNA) Found in the nucleus Controls heredity (inherited traits) Self-replicating Change should result in change in organism

6. Griffiths Experiments Studies pneumonococcus, bacteria that causes pneumonia Two strains of the bacteria: 1) R-strain 2) S-strain

7. R-strain bacteria: rough, nonpathogenic, non-capsulated S-strain: carbohydrate capsule that avoids the immune system and is pathogenic

8. 1) Griffiths innoculates mice with S strain Result: Mice dies (Koch’s postulate)

9. 2.Griffiths injects mice with R-strain bacteria Results: Mice live

10. 3) Heated the S strain and injected into the mice Results: Mouse lives Why? Material is denatured

11. 4. Injected a mixture of heated S strain and normal R strain Results: Mice died Blood shows live S strain

12. Genetic material was released from the S strain and taken up by the R strain to produce S strain bacteria The R strain had transformed into S strain

13. Pneumoniae cell extracts contain protein, DNA, and RNA. How did scientists show that the transforming material was DNA?

14. Avery, MacLeod and McCarthy 1)Mix dead S and Live R bacteria 2) Add protease 3) Add RNA-ase 4) Add DNA-ase

15. Transformation Assimilation of foreign DNA into own DNA

16. Conclusion: DNA is the hereditary material! http://www.youtube.com/watch?v=9hzUjx_oD8E Techno http://www.youtube.com/watch?v=xXbyJNRwjlg