1. Slide 1 of 37 Copyright Pearson Prentice Hall Biology

2. Slide 2 of 37 Griffith and Transformation p287 *What was Griffith trying to learn when he set up this experiment? **What was the control he used? ***How did Griffith show that the disease- causing bacteria were killed by heat? ****What result was Griffith expecting when he injected the mixture of live harmless bacteria and Heat Killed disease causing bacteria? *****Biologists inferred what ? Copyright Pearson Prentice Hall

3. 12–1 DNA Slide 3 of 37 Avery and DNA What was the variable in the experiment? ** How did this experiment show that it was DNA and not any other molecule? Copyright Pearson Prentice Hall

4. 12–1 DNA Slide 4 of 37 Hershey-Chase experiment How were Hershey and Chase able to determine whether bacteriophages injected DNA or protein into bacteria? What would you expect if a bacteriophage injected protein into a bacterial cell? Copyright Pearson Prentice Hall

5. Slide 5 of 37 Copyright Pearson Prentice Hall 12–1 DNA

6. Slide 6 of 37 Copyright Pearson Prentice Hall Griffith and Transformation In 1928, British scientist Fredrick Griffith was trying to learn how certain types of bacteria caused pneumonia. He isolated two different strains of pneumonia bacteria from mice and grew them in his lab.

7. 12–1 DNA Slide 7 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Griffith made two observations: (1) The disease-causing strain of bacteria grew into smooth colonies on culture plates. (2) The harmless strain grew into colonies with rough edges.

8. 12–1 DNA Slide 8 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Griffith's Experiments Griffith set up four individual experiments. Experiment 1: Mice were injected with the disease-causing strain of bacteria. The mice developed pneumonia and died.

9. 12–1 DNA Slide 9 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Experiment 2: Mice were injected with the harmless strain of bacteria. These mice didn’t get sick. Harmless bacteria (rough colonies) Lives

10. 12–1 DNA Slide 10 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Experiment 3: Griffith heated the disease- causing bacteria. He then injected the heat-killed bacteria into the mice. The mice survived. Heat-killed disease- causing bacteria (smooth colonies) Lives

11. 12–1 DNA Slide 11 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Experiment 4: Griffith mixed his heat-killed, disease-causing bacteria with live, harmless bacteria and injected the mixture into the mice. The mice developed pneumonia and died. Live disease- causing bacteria (smooth colonies) Dies of pneumonia Heat-killed disease- causing bacteria (smooth colonies) Harmless bacteria (rough colonies)

12. 12–1 DNA Slide 12 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Griffith concluded that the heat-killed bacteria passed their disease- causing ability to the harmless strain. Live disease- causing bacteria (smooth colonies) Heat-killed disease- causing bacteria (smooth colonies) Harmless bacteria (rough colonies) Dies of pneumonia

13. 12–1 DNA Slide 13 of 37 Copyright Pearson Prentice Hall Griffith and Transformation Transformation Griffith called this process transformation because one strain of bacteria (the harmless strain) had changed permanently into another (the disease-causing strain). Griffith hypothesized that a factor must contain information that could change harmless bacteria into disease-causing ones.

14. 12–1 DNA Slide 14 of 37 Copyright Pearson Prentice Hall Avery and DNA Oswald Avery repeated Griffith’s work to determine which molecule was most important for transformation. Avery and his colleagues made an extract from the heat-killed bacteria that they treated with enzymes.

15. 12–1 DNA Slide 15 of 37 Copyright Pearson Prentice Hall Avery and DNA The enzymes destroyed proteins, lipids, carbohydrates, and other molecules, including the nucleic acid RNA. Transformation still occurred.

16. 12–1 DNA Slide 16 of 37 Copyright Pearson Prentice Hall Avery and DNA Avery and other scientists repeated the experiment using enzymes that would break down DNA. When DNA was destroyed, transformation did not occur. Therefore, they concluded that DNA was the transforming factor.

17. 12–1 DNA Slide 17 of 37 Copyright Pearson Prentice Hall Avery and DNA What did scientists discover about the relationship between genes and DNA?

18. 12–1 DNA Slide 18 of 37 Copyright Pearson Prentice Hall Avery and DNA Avery and other scientists discovered that the nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next.

19. 12–1 DNA Slide 19 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment Alfred Hershey and Martha Chase studied viruses—nonliving particles smaller than a cell that can infect living organisms.

20. 12–1 DNA Slide 20 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment Bacteriophages A virus that infects bacteria is known as a bacteriophage. Bacteriophages are composed of a DNA or RNA core and a protein coat.

21. 12–1 DNA Slide 21 of 37 Copyright Pearson Prentice Hall

22. 12–1 DNA Slide 22 of 37 Copyright Pearson Prentice Hall

23. 12–1 DNA Slide 23 of 37 Copyright Pearson Prentice Hall

24. 12–1 DNA Slide 24 of 37 Copyright Pearson Prentice Hall

25. 12–1 DNA Slide 25 of 37 Copyright Pearson Prentice Hall

26. 12–1 DNA Slide 26 of 37 Copyright Pearson Prentice Hall

27. 12–1 DNA Slide 27 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment When a bacteriophage enters a bacterium, the virus attaches to the surface of the cell and injects its genetic information into it. The viral genes produce many new bacteriophages, which eventually destroy the bacterium. When the cell splits open, hundreds of new viruses burst out.

28. 12–1 DNA Slide 28 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment If Hershey and Chase could determine which part of the virus entered an infected cell, they would learn whether genes were made of protein or DNA. They grew viruses in cultures containing radioactive isotopes of phosphorus-32 ( 32 P) and sulfur-35 ( 35 S).

29. 12–1 DNA Slide 29 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment If 35 S was found in the bacteria, it would mean that the viruses’ protein had been injected into the bacteria. Bacteriophage with sulfur-35 in protein coat Phage infects bacterium No radioactivity inside bacterium

30. 12–1 DNA Slide 30 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment If 32 P was found in the bacteria, then it was the DNA that had been injected. Bacteriophage with phosphorus-32 in DNA Phage infects bacterium Radioactivity inside bacterium

31. 12–1 DNA Slide 31 of 37 Copyright Pearson Prentice Hall The Hershey-Chase Experiment Nearly all the radioactivity in the bacteria was from phosphorus ( 32 P). Hershey and Chase concluded that the genetic material of the bacteriophage was DNA, not protein.

32. 12–1 DNA Slide 32 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA What is the overall structure of the DNA molecule?

33. 12–1 DNA Slide 33 of 37 Copyright Pearson Prentice Hall

34. 12–1 DNA Slide 34 of 37 P291: answer the following: 1-what is a nucleotide? Draw and label 2-what is difference between purines & pyrimidines? 3- what 2 things make up “backbone” of DNA? 4-what bond joins bases together to form double helix? Copyright Pearson Prentice Hall

35. 12–1 DNA Slide 35 of 37 EOC objective: Investigate how genetic information is encoded in nucleic acids. Identify the structure and function of DNA. Copyright Pearson Prentice Hall

36. 12–1 DNA Slide 36 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA DNA is made up of nucleotides. A nucleotide is a monomer of nucleic acids made up of a five-carbon sugar called deoxyribose, a phosphate group, and a nitrogenous base.

37. 12–1 DNA Slide 37 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA There are four kinds of bases in in DNA: adenine guanine cytosine thymine

38. 12–1 DNA Slide 38 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA The backbone of a DNA chain is formed by sugar and phosphate groups of each nucleotide. The nucleotides can be joined together in any order.

39. 12–1 DNA Slide 39 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA Chargaff's Rules Erwin Chargaff discovered that: The percentages of guanine [G] and cytosine [C] bases are almost equal in any sample of DNA. The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA.

40. 12–1 DNA Slide 40 of 37 If DNA analysis has 24% A, what is amt. of T? What is amt. of C and G? Copyright Pearson Prentice Hall

41. 12–1 DNA Slide 41 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA X-Ray Evidence Rosalind Franklin used X-ray diffraction to get information about the structure of DNA. She aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film.

42. 12–1 DNA Slide 42 of 37 Copyright Pearson Prentice Hall

43. 12–1 DNA Slide 43 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA The Double Helix Using clues from Franklin’s pattern, James Watson and Francis Crick built a model that explained how DNA carried information and could be copied. Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other.

44. 12–1 DNA Slide 44 of 37 Copyright Pearson Prentice Hall

45. 12–1 DNA Slide 45 of 37 Copyright Pearson Prentice Hall

46. 12–1 DNA Slide 46 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA DNA Double Helix

47. 12–1 DNA Slide 47 of 37 Copyright Pearson Prentice Hall

48. 12–1 DNA Slide 48 of 37 Copyright Pearson Prentice Hall The Components and Structure of DNA Watson and Crick discovered that hydrogen bonds can form only between certain base pairs—adenine and thymine, and guanine and cytosine. This principle is called base pairing.

49. - or - Continue to: Click to Launch: Slide 49 of 37 Copyright Pearson Prentice Hall 12–1

50. Slide 50 of 37 Copyright Pearson Prentice Hall 12–1 Avery and other scientists discovered that a.DNA is found in a protein coat. b.DNA stores and transmits genetic information from one generation to the next. c.transformation does not affect bacteria. d.proteins transmit genetic information from one generation to the next.

51. Slide 51 of 37 Copyright Pearson Prentice Hall 12–1 The Hershey-Chase experiment was based on the fact that a.DNA has both sulfur and phosphorus in its structure. b.protein has both sulfur and phosphorus in its structure. c.both DNA and protein have no phosphorus or sulfur in their structure. d.DNA has only phosphorus, while protein has only sulfur in its structure.

52. Slide 52 of 37 Copyright Pearson Prentice Hall 12–1 DNA is a long molecule made of monomers called a.nucleotides. b.purines. c.pyrimidines. d.sugars.

53. Slide 53 of 37 Copyright Pearson Prentice Hall 12–1 Chargaff's rules state that the number of guanine nucleotides must equal the number of a.cytosine nucleotides. b.adenine nucleotides. c.thymine nucleotides. d.thymine plus adenine nucleotides.

54. Slide 54 of 37 Copyright Pearson Prentice Hall 12–1 In DNA, the following base pairs occur: a.A with C, and G with T. b.A with T, and C with G. c.A with G, and C with T. d.A with T, and C with T.

55. END OF SECTION