How to Use This Presentation

Transcription

1 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 Chapter Presentation Bellringers Transparencies Standardized Test Prep Image and Math Focus Bank Visual Concepts

3 Genes and DNA Table of Contents Section 1 What Does DNA Look Like? Section 2 How DNA Works

4 Section 1 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 Section 1 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 Section 1 What Does DNA Look Like? The Pieces of the Puzzle DNA stands for deoxyribonucleic acid. DNA is the genetic material that determines inherited characteristics. Nucleotides: The Subunits of DNA DNA is made of subunits called nucleotides. A nucleotide consists of a sugar, a phosphate, and a base.

7 Section 1 What Does DNA Look Like? The Pieces of the Puzzle, continued Chargaff s Rule Erwin 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 Discovery Chemist Rosalind Franklin was able to make images of DNA molecules by using X-ray diffraction.

8 Section 1 What Does DNA Look Like? The Pieces of the Puzzle, continued Watson and Crick s Model James 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 Section 1 What Does DNA Look Like? DNA s Double Structure The Double Helix The 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 Section 1 What Does DNA Look Like?

11 Section 1 What Does DNA Look Like? Making Copies of DNA How Copies Are Made During 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 Made DNA is copied every time a cell divides. Each new cell gets a complete copy of all the DNA.

12 Section 1 What Does DNA Look Like? Making Copies of DNA, continued

13 Section 1 What Does DNA Look Like? DNA Replication Click below to watch the Visual Concept. Visual Concept You may stop the video at any time by pressing the Esc key.

14 Section 2 How DNA Works 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 Section 2 How DNA Works Objectives Explain the 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 Section 2 How DNA Works 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 Section 2 How DNA Works

18 Section 2 How DNA Works Genes and Proteins Proteins and Traits Proteins act as chemical triggers for many of the processes within cells. Proteins help determine traits. Help from RNA Another 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 Section 2 How DNA Works Genes and Proteins, continued The Making of a Protein The 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 Section 2 How DNA Works

21 Section 2 How DNA Works

22 Section 2 How DNA Works Changes in Genes Mutations Changes in the number, type, or order of bases on a piece of DNA are known as mutations.

23 Section 2 How DNA Works 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 Section 2 How DNA Works Carcinogens and Mutagens Click below to watch the Visual Concept. Visual Concept You may stop the video at any time by pressing the Esc key.

25 Section 2 How DNA Works 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 Section 2 How DNA Works

27 Section 2 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 Identification Your 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 Genes and DNA Concept Map Use the terms below to complete the concept map on the next slide. mutation amino acid nucleotide DNA adenine genes guanine proteins chromosomes cytosine

29 Genes and DNA

30 Genes and DNA

31 End of Chapter C4 Show

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

33 Standardized Test Preparation Passage 1 The 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 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 1. What does the first sentence in this passage describe? A the air pollution in a particular place B the feeling that a person might experience during an event C the motion of an object D the reason that a person was probably guilty of a crime

36 Standardized Test Preparation 1. What does the first sentence in this passage describe? A the air pollution in a particular place B the feeling that a person might experience during an event C the motion of an object D the reason that a person was probably guilty of a crime

37 Standardized Test Preparation 2. Which of the following best describes the main idea of the second paragraph of this passage? F A defendant was proven guilty by DNA analysis. G Court battles involving DNA fingerprinting are very exciting. H The technique of DNA profiling is increasingly used in court cases. I The technique of DNA profiling is controversial.

38 Standardized Test Preparation 2. Which of the following best describes the main idea of the second paragraph of this passage? F A defendant was proven guilty by DNA analysis. G Court battles involving DNA fingerprinting are very exciting. H The technique of DNA profiling is increasingly used in court cases. I The technique of DNA profiling is controversial.

39 Standardized Test Preparation Passage 2 Most 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 Passage 2, continued Some 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 1. In the passage, what does biochemical mean? A a chemical found in nonliving things B a chemical found in living things C a pair of chemicals D a protein

42 Standardized Test Preparation 1. In the passage, what does biochemical mean? A a chemical found in nonliving things B a chemical found in living things C a pair of chemicals D a protein

43 Standardized Test Preparation 2. According to the passage, which of the following statements is true? F Amino acids contain carbon dioxide. G Amino acids contain proteins. H Proteins are made of living things. I Proteins are made of amino acids.

44 Standardized Test Preparation 2. According to the passage, which of the following statements is true? F Amino acids contain carbon dioxide. G Amino acids contain proteins. H Proteins are made of living things. I Proteins are made of amino acids.

45 Standardized Test Preparation 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 1. In which mutation was an original base pair replaced? A Mutation A B Mutation B C Mutation C D There is not enough information to determine the answer.

47 Standardized Test Preparation 1. In which mutation was an original base pair replaced? A Mutation A B Mutation B C Mutation C D There is not enough information to determine the answer.

48 Standardized Test Preparation 2. In which mutation was a new base pair added? F Mutation A G Mutation B H Mutation C I There is not enough information to determine the answer.

49 Standardized Test Preparation 2. In which mutation was a new base pair added? F Mutation A G Mutation B H Mutation C I There is not enough information to determine the answer.

50 Standardized Test Preparation 3. In which mutation was an original base pair removed? A Mutation A B Mutation B C Mutation C D There is not enough information to determine the answer.

51 Standardized Test Preparation 3. In which mutation was an original base pair removed? A Mutation A B Mutation B C Mutation C D There is not enough information to determine the answer.

52 Standardized Test Preparation Math Read each question, and choose the best answer.

53 Standardized Test Preparation 1. Mary was making a design on top of her desk with marbles. She put 3 marbles in the first row, 7 marbles in the second row, 15 marbles in the third row, and 31 marbles in the fourth row. If Mary continues this pattern, how many marbles will she put in the seventh row? A 46 B 63 C 127 D 25500

54 Standardized Test Preparation 1. Mary was making a design on top of her desk with marbles. She put 3 marbles in the first row, 7 marbles in the second row, 15 marbles in the third row, and 31 marbles in the fourth row. If Mary continues this pattern, how many marbles will she put in the seventh row? A 46 B 63 C 127 D 25500

55 Standardized Test Preparation 2. Bobby walked 3 1/2 km on Saturday, 2 1/3 km on Sunday, and 1 km on Monday. How many kilometers did Bobby walk on those 3 days? F 5 1/6 G 5 5/6 H 6 1/6 I 6 5/6

56 Standardized Test Preparation 2. Bobby walked 3 1/2 km on Saturday, 2 1/3 km on Sunday, and 1 km on Monday. How many kilometers did Bobby walk on those 3 days? F 5 1/6 G 5 5/6 H 6 1/6 I 6 5/6

57 Standardized Test Preparation 3. Marie bought a new aquarium for her goldfish. The aquarium is 60 cm long, 20 cm wide, and 30 cm high. Which equation could be used to find the volume of water needed to fill the aquarium to 25 cm deep? A V B V C V D V

58 Standardized Test Preparation 3. Marie bought a new aquarium for her goldfish. The aquarium is 60 cm long, 20 cm wide, and 30 cm high. Which equation could be used to find the volume of water needed to fill the aquarium to 25 cm deep? A V B V C V D V

59 Standardized Test Preparation 4. How is the product of expressed in scientific notation? F G H I 24 6

60 Standardized Test Preparation 4. How is the product of expressed in scientific notation? F G H I 24 6

61 Section 1 What Does DNA Look Like?

62 Section 1 What Does DNA Look Like?

63 Section 2 How DNA Works

64 Standardized Test Preparation

65 Standardized Test Preparation