How to Use This Presentation

1. How to Use This Presentation How to Use This Presentation • To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show”, or simply press F5 on the top row of your keyboard. • To advance to the next slide click the left mouse button once. • From the Chapter screen you can click on any section to go directly to that section’s presentation. • Blank or “missing” areas of a slide will remain hidden until the left mouse button is clicked. • You may exit the slide show at any time by pressing the Esc key.

2. Resources Bellringers Chapter Presentation Transparencies Standardized Test Prep Image and Math Focus Bank CNN Videos Visual Concepts

3. Genes and DNA Chapter 6 Table of Contents Section 1 What Does DNA Look Like? Section 2 How DNA Work

4. Chapter 6 Section1 What Does DNA Look Like? Bellringer • Can you explain the difference between traits and characteristics? Which is more closely associated with DNA and genes? Do you know where DNA and genes are found in the body? In specific cells? • Write your answers in your science journal.

5. Chapter 6 Section1 What Does DNA Look Like? Objectives • List three important events that led to understanding the structure of DNA. • Describe the basic structure of a DNA molecule. • Explain how DNA molecules can be copied.

6. Chapter 6 Section1 What Does DNA Look Like? The Pieces of the Puzzle • DNAstands for deoxyribonucleic acid. DNA is the genetic material that determines inherited characteristics. • Nucleotides: The Subunits of DNADNA is made of subunits called nucleotides. A nucleotide consists of a sugar, a phosphate, and a base.

7. Chapter 6 Section1 What Does DNA Look Like? The Pieces of the Puzzle, continued • Chargaff’s RuleErwin Chargaff found that the amount of adenine in DNA always equals the amount of thymine, and the amount of guanine always equals the amount of cytosine. • Franklin’s DiscoveryChemist Rosalind Franklin was able to make images of DNA molecules by using X-ray diffraction.

8. Chapter 6 Section1 What Does DNA Look Like? The Pieces of the Puzzle, continued • Watson and Crick’s ModelJames Watson and Francis Crick used Chargaff’s and Franklin’s research to build a model of DNA. • The model, which looked like a long, twisted ladder, eventually helped explain how DNA is copied and how it functions in the cell.

9. Chapter 6 Section1 What Does DNA Look Like? DNA’s Double Structure • The Double HelixThe shape of DNA is known as a double helix. • The two sides of the ladder are made of alternating sugar parts and phosphate parts. • The rungs of the ladder are made of a pair of bases.

10. Chapter 6 Section1 What Does DNA Look Like?

11. Section1 What Does DNA Look Like? Chapter 6 Making Copies of DNA • How Copies Are MadeDuring replication,a DNA molecule is split down the middle, where the bases meet. The bases on each side of the molecule are used as a pattern for a new strand. • When Copies Are MadeDNA is copied every time a cell divides. Each new cell gets a complete copy of all the DNA.

12. Section1 What Does DNA Look Like? Chapter 6 Making Copies of DNA, continued

13. Section1 What Does DNA Look Like? Chapter 6 DNA Replication Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

14. Section2 How DNA Works Chapter 6 Bellringer • Unscramble the following words: • tpsoneir • neesg • Now think of three words you associate with each of the above words and use them all in a paragraph that highlights what you know about DNA. • Write your paragraph in your science journal.

15. Section2 How DNA Works Chapter 6 Objectives • Explainthe relationship between DNA, genes, and proteins. • Outline the basic steps in making a protein. • Describe three types of mutations, and provide an example of a gene mutation. • Describe two examples of uses of genetic knowledge.

16. Section2 How DNA Works Chapter 6 Unraveling DNA • DNA is often wound around proteins, coiled into strands, and then bundled up even more. In a cell that has a nucleus, the strands of DNA and proteins are bundled into chromosomes. • A gene consists of a string of nucleotides that give the cell information about how to make a specific trait.

17. Chapter 6 Section2 How DNA Works

18. Section2 How DNA Works Chapter 6 Genes and Proteins • Proteins and Traits Proteins act as chemical triggers for many of the processes within cells. Proteins help determine traits. • Help from RNAAnother type of molecule that helps make proteins is called RNA, or ribonucleic acid. RNA is so similar to DNA that RNA can serve as a temporary copy of a DNA sequence.

19. Section2 How DNA Works Chapter 6 Genes and Proteins, continued • The Making of a ProteinThe first step in making a protein is to copy one side of the segment of DNA containing a gene. This copy is called messenger RNA (mRNA). • A ribosome is a cell organelle composed of RNA and protein. A ribosome uses mRNA, transfer RNA (tRNA), and amino acids to make proteins. • You can see the steps of protein production on the following two slides.

20. Section2 How DNA Works Chapter 6

21. Section2 How DNA Works Chapter 6

22. Section2 How DNA Works Chapter 6 Changes in Genes • Mutations Changes in the number, type, or order of bases on a piece of DNA are known as mutations.

23. Section2 How DNA Works Chapter 6 Changes in Genes, continued • Do Mutations Matter?There are three possible consequences to changes in DNA: an improved trait, no change, or a harmful trait. • How Do Mutations Happen?Mutations happen regularly because of random errors when DNA is copied. Any physical or chemical agent that can cause a mutation in DNA is called a mutagen.

24. Section2 How DNA Works Chapter 6 Carcinogens and Mutagens Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

25. Section2 How DNA Works Chapter 6 An Example of Substitution • A mutation, such as a substitution, can be harmful because it may cause a gene to produce the wrong protein. • A simple change in an amino acid can cause a disease such as sickle cell anemia, as shown on the next slide.

26. Section2 How DNA Works Chapter 6

27. Chapter 6 Section2 How DNA Works Uses of Genetic Knowledge • Genetic Engineering Scientists can manipulate individual genes within organisms. This kind of manipulation is called genetic engineering. • Genetic IdentificationYour DNA is unique, so it can be used like a fingerprint to identify you. DNA fingerprinting identifies the unique patterns in an individual’s DNA.

28. Chapter 6 Genes and DNA Concept Map Use the terms below to complete the concept map on the next slide.

29. Concept Map Chapter 6

30. Chapter 6 Concept Map

31. End of Chapter 6 Show

32. Standardized Test Preparation Chapter 6 Reading Read each of the passages. Then, answer the questions that follow each passage.

33. Standardized Test Preparation Chapter 6 Passage 1The tension in the courtroom was so thick that you could cut it with a knife. The prosecuting attorney presented this evidence: “DNA analysis indicates that blood found on the defendant’s shoes matches the blood of the victim. The odds of this match happening by chance are 1 in 20 million.” The jury members were stunned by these figures. Can there be any doubt that the defendant is guilty? Continued on the next slide

34. Standardized Test Preparation Chapter 6 Passage 1, continued DNA is increasingly used as evidence in court cases. Traditional fingerprinting has been used for more than 100 years, and it has been an extremely important identification tool. Recently, DNA fingerprinting, also called DNA profiling, has started to replace traditional techniques. DNA profiling has been used to clear thousands of wrongly accused or convicted individuals. However, there is some controversy over whether DNA evidence should be used to prove a suspect’s guilt.

35. Standardized Test Preparation Chapter 6 1. What does the first sentence in this passage describe? Athe air pollution in a particular place Bthe feeling that a person might experience during an event Cthe motion of an object Dthe reason that a person was probably guilty of a crime

36. Standardized Test Preparation Chapter 6 1. What does the first sentence in this passage describe? Athe air pollution in a particular place Bthe feeling that a person might experience during an event Cthe motion of an object Dthe reason that a person was probably guilty of a crime

37. Standardized Test Preparation Chapter 6 2. Which of the following best describes the main idea of the second paragraph of this passage? FA defendant was proven guilty by DNA analysis. GCourt battles involving DNA fingerprinting are very exciting. HThe technique of DNA profiling is increasingly used in court cases. IThe technique of DNA profiling is controversial.

38. Standardized Test Preparation Chapter 6 2. Which of the following best describes the main idea of the second paragraph of this passage? FA defendant was proven guilty by DNA analysis. GCourt battles involving DNA fingerprinting are very exciting. HThe technique of DNA profiling is increasingly used in court cases. IThe technique of DNA profiling is controversial.

39. Standardized Test Preparation Chapter 6 Passage 2Most of the biochemicals found in living things are proteins. In fact, other than water, proteins are the most abundant molecules in your cells. Proteins have many functions, including regulating chemical activities, transporting and storing materials, and providing structural support. Every protein is composed of small “building blocks” called amino acids. Amino acids are molecules that are composed of carbon, hydrogen, oxygen, and nitrogen atoms. Continued on the next slide

40. Standardized Test Preparation Chapter 6 Passage 2, continuedSome amino acids also include sulfur atoms. Amino acids chemically bond to form proteins of many shapes and sizes. The function of a protein depends on the shape of the bonded amino acids. If even a single amino acid is missing or out of place, the protein may not function correctly or may not function. Foods such as meat, fish, cheese, and beans contain proteins, which are broken down into amino acids as the foods are digested. Your body can then use these amino acids to make new proteins.

41. Standardized Test Preparation Chapter 6 1. In the passage, what does biochemical mean? Aa chemical found in nonliving things Ba chemical found in living things Ca pair of chemicals Da protein

42. Standardized Test Preparation Chapter 6 1. In the passage, what does biochemical mean? Aa chemical found in nonliving things Ba chemical found in living things Ca pair of chemicals Da protein

43. Standardized Test Preparation Chapter 6 2. According to the passage, which of the following statements is true? FAmino acids contain carbon dioxide. GAmino acids contain proteins. HProteins are made of living things. IProteins are made of amino acids.

44. Standardized Test Preparation Chapter 6 2. According to the passage, which of the following statements is true? FAmino acids contain carbon dioxide. GAmino acids contain proteins. HProteins are made of living things. IProteins are made of amino acids.

45. Standardized Test Preparation Chapter 6 Interpreting Graphics The diagram below shows an original sequence of DNA and three possible mutations. Use the diagram to answer the questions that follow.

46. Standardized Test Preparation Chapter 6 1. In which mutation was an original base pair replaced? AMutation A BMutation B CMutation C DThere is not enough information to determine the answer.

47. Standardized Test Preparation Chapter 6 1. In which mutation was an original base pair replaced? AMutation A BMutation B CMutation C DThere is not enough information to determine the answer.

48. Standardized Test Preparation Chapter 6 2. In which mutation was anew base pair added? FMutation A GMutation B HMutation C IThere is not enough information to determine the answer.

49. Standardized Test Preparation Chapter 6 2. In which mutation was anew base pair added? FMutation A GMutation B HMutation C IThere is not enough information to determine the answer.

50. Standardized Test Preparation Chapter 6 3. In which mutation was an original base pair removed? AMutation A BMutation B CMutation C DThere is not enough information to determine the answer.