Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. How to Use This Presentation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter Presentation Transparencies Image and Math Focus Bank Bellringers Standardized Test Prep Visual Concepts Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Table of Contents Section 1 What Does DNA Look Like? Section 2 How DNA Works Chapter 6 Genes and DNA

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? The Pieces of the Puzzle DNA stands for deoxyribonucleic acid. DNA is *. Chapter 6 Nucleotides: The Subunits of DNA DNA is made of subunits called nucleotides. A nucleotide consists of a sugar, a phosphate, and a base.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? The Pieces of the Puzzle, continued Chargaff’s Rule Erwin Chargaff found that the amount of *. Franklin’s Discovery Chemist Rosalind Franklin was able to make images of DNA molecules by using *. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? DNA’s Double Structure The Double Helix The shape of DNA is *. 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? Making Copies of DNA, continued Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 What Does DNA Look Like? DNA Replication Chapter 6 Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Genes and Proteins Chapter 6 Proteins and Traits Proteins act as *. Help from RNA Another type of molecule that helps make proteins is called *.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Genes and Proteins, continued Chapter 6 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 *. A ribosome is a cell organelle composed of RNA and protein. A ribosome uses *. You can see the steps of protein production on the following two slides.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Changes in Genes Mutations *. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Changes in Genes, continued Do Mutations Matter? There are three possible consequences to changes in DNA: *. How Do Mutations Happen? Mutations happen regularly because of random errors when DNA is copied. * is called a mutagen. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Carcinogens and Mutagens Chapter 6 Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 How DNA Works Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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 *. Chapter 6

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Interpreting Graphics The diagram below shows an original sequence of DNA and three possible mutations. Use the diagram to answer the questions that follow. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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. Chapter 6 Standardized Test Preparation