Inquiry Lesson Plan Topic: DNA Grade Level: 6-8 Time Allotment: three-four 30-45 minute sessions Objectives: The students will be able to understand that chromosomes are structures in the nucleus of a cell that carry genes. Also, students will understand that genes are smaller units that contain the heredity code, DNA. Students will understand that the genetic code is transmitted biochemically through molecules called deoxyribonucleic acid. Finally, students will understand the structure of the DNA molecule. Standards: Illinois Learning Standards 11.B.2 Plan and construct technological design, incorporating the safety and procedural guidelines into the construction plan, or maximizing resource capabilities. 11.B.5 Communicate the results of design investigation presenting an oral and/or written report, explaining the test of the scientific principle, using available technologies, relating anecdotal and quantitative observations, or generating additional design modifications which can be tested later. 12.A.2 Apply scientific inquiries or technological designs to explore the basic roles of genes and chromosomes in transmitting traits over generations, describing how physical traits are transmitted through sexual or asexual reproductive processes, charting pedigree probabilities for transmissions, identifying examples of selective breeding for particular traits, or analyzing how familiar human diseases are related to genetic mutations. 13.A.1a Use basic safety practices. 13.A.1c Explain how knowledge can be gained by careful observation. Materials: For this activity you will need: Day 1: White Board, Markers, Pencils, Handout for Notes on DNA, Notebook Paper Day 2: • Two 24-inch pieces of fishing line • Eight 2-inch pieces of blue chenille stems (pipe cleaners) • Eight 2-inch pieces of green chenille stems • Eight 2-inch pieces of purple chenille stems • Eight 2-inch pieces of orange chenille stems • Eighteen pieces of dried pinwheel pasta • Sixteen pieces of dried ziti cut pasta Day 3-4: DNA activity sheet, white board, markers, Pencils, DNA notes Inquiry Lesson Plan Procedures: Day 1: STEP 1 Think About it – Engagement A) Check background knowledge of DNA. What are chromosomes? What are genes? What is DNA? How does DNA work? B) Expository Learning of DNA - Explain that organisms carry an elaborate blueprint containing the information necessary to develop and maintain life. This “manual of instructions” is located in a chemical molecule called DNA. DNA is found within a person’s genes. Genes are small structures found in chromosomes, structures within the nucleus of cells. -Tell students that DNA works something like the alphabet. While the alphabet has 26 letters, DNA’s “alphabet” has only four letters. These letters are guanine (G), adenine (A), cytosine (C), and thymine (T). Just as the 26 letters of the alphabet can be used to form millions of words for communication, DNA’s alphabet can be combined to form codes with more than five billion combinations of G’s, A’s, T’s, and C’s. The differences in these combinations result in differences among human beings. C) Inquiry Learning of DNA - Have children brainstorm some traits that are passed on from their parents. For example, eye color, hair color, facial characteristics, etc. Write these down on a piece of paper. - Partnering students up, have them discuss the traits that have been passed down to them from their parents. Then have them discuss how these traits are passed down from one generation to the next. The students should understand that genes are passed on from one generation to the next. What is the makeup of the DNA in the genes? How are traits passed on? Day 2: STEP 2 Investigate – Explore Part A. The DNA molecule consists of two strands that form a double helix, a spiraling shape much like a twisted ladder. The DNA molecule has a sugar component, a phosphate component, and four different bases—adenine, thymine, cytosine, and guanine. To help students understand how these components fit together to form DNA, have each student make a model of DNA with fishing line, dried pasta, and differentcolored pipe cleaners. Part B. Have student gather the material for their DNA • Two 24-inch pieces of fishing line • Eight 2-inch pieces of blue chenille stems (pipe cleaners) • Eight 2-inch pieces of green chenille stems • Eight 2-inch pieces of purple chenille stems Inquiry Lesson Plan • Eight 2-inch pieces of orange chenille stems • Eighteen pieces of dried pinwheel pasta • Sixteen pieces of dried ziti cut pasta Part C. 1. First, give each student 2 pieces of line, 18 pieces of pinwheel pasta, 16 pieces of ziti pasta, and different-colored chenille stems (pipe cleaners). Explain that the pinwheel pasta represents the sugar component, the ziti pasta the phosphate, and the chenille stems each of the bases. 2. Tell students to start with the pinwheel pasta and alternate with the ziti pasta as they thread the pasta on the line. On each line, they should string nine pieces of pinwheel pasta alternating with eight pieces of ziti. Wrap the line around the final piece of pasta at the end of each line so that the pasta does not fall off. After pasta has been strung on both lines, each line should have a total of 17 alternating pieces of pasta. Have students lay the two lines side by side. 3. Then give students the “code” for the chenille stems—the blue stem represents adenine; the green stem, thymine; the purple stem, cytosine; and the orange stem, guanine. Explain that the bases in DNA are found in pairs and that adenine always pairs with thymine and cytosine always pairs with guanine. 4. Have students represent these base pairs with twisted chenille stems. First, have them twist the eight blue stems and eight green stems together, making a total of eight bluegreen stems, about 2 inches long. Likewise, have them twist the eight purple and eight orange stems together, making a total of eight purple-orange stems, about 2 inches long. Students will find that the chenille stems twist together easily. 5. Now, have students create a “ladder” using the pasta lines as the sides and the twisted chenille stems as steps. Beginning at the top, students should connect the two ends of a twisted chenille stem to the top pasta pieces on the two lines. Then use a second chenille stem to connect the next two pasta pieces directly across from each other. They should continue building their ladder, one step at a time, until they have connected the bottom two pieces of pasta. Remind them that they can place the twisted chenille stems in any order. (The blue-green stems do not have to alternate with the orange-purple stems.) After all the stems have been woven, the DNA model is complete. Part D. -Have students discuss their model in front of the class, discussing the shape of the DNA molecule and reviewing the four bases of their model. Day 2: STEP 3 Reflecting upon the Activity and the Investigation Questions – Explain How do the bases pair up in a DNA molecule? How does your model help you figure this out? Inquiry Lesson Plan What differentiates one DNA molecule from another? How could you change your DNA model to reflect changes among DNA molecules? How do you think a DNA molecule makes an exact copy of itself? How does its structure help it do so? Day 3: STEP 4 Digging Deeper – Explain Basic Structure - Learning about basic characteristics of DNA we learned that DNA molecule consists of two strands that form a double helix, a spiraling shape much like a twisted ladder. The DNA molecule has a sugar component, a phosphate component, and four different bases—adenine, thymine, cytosine, and guanine - By making the DNA molecule with the pasta we learned that in DNA are found in pairs and that adenine always pairs with thymine and cytosine always pairs with guanine. More Understanding Chromosomes -The chromosome is a threadlike strand of DNA that is found in the nucleus of the cell. These chromosomes come in pairs and normally there are 23 pairs of chromosomes (46 total chromosomes. Of those, 1 pair is the sex chromosomes (determines whether you are Inquiry Lesson Plan male or female, plus some other body characteristics), and the other 22 pairs are autosomal chromosomes (determine the rest of the body’s makeup).Half of them come from mom and half of them come from dad. Genes - A gene is a distinct portion of a cell’s DNA. Genes are coded instructions for making everything the body needs, especially proteins. Human beings have about 25,000 genes. Other Useful terms in understanding DNA amino acids Definition: The essential building blocks of life. Context: Amino acids provide the structural components of cells and tissues. chromosome Definition: A structure found in the nucleus of cells. Context: Chromosomes carry genes, smaller units that contain DNA, the code of life cloning Definition: To create progeny asexually. Context: Dolly the sheep is recognized as the first mammal created through cloning DNA Definition: The genetic material contained in every cell and unique to each individual. Context: DNA is responsible for the enormous possibilities for variability in the living world. enzyme Definition: A complex protein that can catalyze biochemical reactions in the body. Context: In addition to determining heredity, genes also carry the information needed for constructing enzymes needed for essential biochemical reactions. genetics Inquiry Lesson Plan Definition: The study of what genes are made of, how they work, and how they are inherited. Context: The field of genetics includes understanding how living systems grow and are maintained during their life span and how they duplicate and pass on genetic material. heredity Definition: The transfer within a species of characteristics from one generation to another. Context: Heredity is responsible for how we look, what we are interested in, and in some cases, what diseases we may get during our lifetime. nucleotide Definition: The basic structural unit of DNA. Context: Each strand of a DNA molecule is a linear arrangement of nucleotides, which are each composed of one sugar, one phosphate, and one nitrogenous base. nucleus Definition: A body found in most plant and animal cells that contains the genetic material. Context: Scientists were able to break the genetic code within the nucleus of cells. polypeptide Definition: A molecular chain of amino acids. Context: Proteins are actually polypeptides, chains of more than two amino acids. protein Definition: A large, complex molecule made up of amino acids. Context: Human beings can synthesize at least 100,000 different kinds of proteins. Sum it up We now know that chromosomes are found in the nucleus of cells that carry genes, which hold DNA. DNA is the genetic material contained in every cell and unique to each individual. Yesterday I had you discuss some common traits you have with your parents and how these traits are passed down. Now you know that the chromosomes that are passed on from your parents (23 from mom, and 23 from dad) hold DNA which is that genetic material that carries the traits that you possess. DNA consists of two strands that form a double helix, a spiraling shape much like a twisted ladder. The DNA molecule has a sugar component, a phosphate component, and four different bases—adenine, thymine, cytosine, and guanine. Day 4: STEP 5 Understanding and Applying What You Have Learned Elaborate The following is a puzzle that you could solve using the terms you learned through this lesson. Inquiry Lesson Plan FUN WITH WORDS PUZZLE Reference: Puzzle Maker: http://puzzlemaker.school.discovery.com/CrissCrossSetupForum.html DNA Across 2. A complex protein that can catalyze biochemical reactions in the body. 3. A distinct portion of a cell’s DNA. 5. Genetic material contained in every cell and unique to each individual. 9. A molecular chain of amino acids. 11. Structure found in the nucleus of cells. 12. A body found in most plant and animal cells that contains the genetic material. Down 1. The transfer within a species of characteristics from one generation to another. 4. The basic structural unit of DNA. 6. Acid The essential building blocks of life. 7. To create progeny asexually. 8. The study of what genes are made of, how they work, and how they are inherited. 10. A large, complex molecule made up of amino acids. Inquiry Lesson Plan Day 4: STEP 6 Inquiring Further –Elaborate / Evaluate Understanding Further Design and create a DNA model using materials of your own choice. Suggested materials include stained glass, clay, beads, buttons, wood pieces, recycled materials, and food items. They should include a key that explains what each item represents. After students have completed their models, have them display the models in the classroom. This will help students further understand the structure of the DNA because they will be setting their own key for their items. Inquiring Further Genetic abnormalities occur quite frequently in newborn babies. For example, a child might be born with Down Syndrome. What occurs in the genetic makeup of the child to make them have this genetic disorder? Take the time to look up three genetic disorders and give an explanation of what occurs in these children. Day 4: STEP 7 Assessment –Evaluate Objectives Understand that chromosomes are structures in the nucleus of a cell that carry genes Location of Activity Investigate Digging Deeper Understanding & Applying Understand that genes are smaller units that contain the hereditary code, DNA Investigate Digging Deeper Understanding & Applying Understand that the genetic code is transmitted biochemically through molecules called deoxyribonucleic acid (DNA) Understand the structure of the DNA molecule Digging Deeper Investigate Digging Deeper Understanding & Applying Assessment Opportunity Discuss with students to check for understanding. Check for understanding through the application. Discuss with students to check for understanding. Check for understanding through the application. Discuss with students to check for understanding. Students will be graded on the structure of DNA that they make. Also, understanding will be checked through discussion. Inquiry Lesson Plan Rubric Delivery Participation Completeness 3 The student showed enthusiasm while presenting his/her DNA molecule in a clear and organized manor The student preformed well within their group. He/she also demonstrated his/her knowledge about previous vocabulary and presented creative brainstorming ideas The student’s DNA was neatly completed with all the correct pieces in place. This was done within an allotted time period. 2 The student presented his/her DNA molecule in a clear manor 1 The student demonstrated very little effort while presenting his/her DNA molecule. The student tried to work effectively within the groups and showed some understanding of the vocabulary The student showed lack of participation within the group and little class discussion. The student’s DNA was completed with all the correct pieces in place. The student’s DNA was incorrect and proper procedures were not followed. Reference: Goldfein, W. (2008). Building a model DNA. Retrieved February 4, 2010, From Discovery Education Web Site http://school.discoveryeducation.com/lessonplans/programs/modeldna/#eva