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Wood to Wheels- Inquiry Lesson Plan Lesson Introduction Title: Bioenergy in the Classroom Subject/ target grade: 9-11 Duration: approximately 6 days (55 minute class periods) o Greener Diet Article: ½ day – follow with powerpoint (55 minute class period) o Growing Fuel Powerpoint:: 2-3 days (55 minute class period) o Wheat Germ DNA Extraction Lab: 1 day (55-70 minute class period) o DNA Decoder activity: 1 day (55-70 minute class period) Setting: classroom Learning Objectives: Students will be able to…. o Describe how food and food production affect global warming o Identify the 4 nitrogenous bases associated with DNA o “Decode” a hypothetical strand of DNA o Describe the structure and components of cell walls o Improve a hypothetical “cell wall” by creating genetic modifications through peer collaboration o Articulate 2 challenges facing scientists who are working on biofuels and 2 possible solutions Michigan Content Expectations: Inquiry, Reflection and Social Implications B1.1C: Generate questions from investigations B1.1E: Give evidence to support conclusions B1.2B: Apply science to social issues B1.2E: Be aware of careers in science B1.2i: Explain progressions of ideas B1.2k: Analyze how science and society interact Chemistry and Biochemistry B2.2f: Explain the role of enzymes and other proteins in biochemical functions B2.5A: Recognize and explain that macromolecules such as lipids contain high energy bonds Cell Structure and Function B2.5i: Relate cell parts/organelles to their function Homeostasis and Health B2.3A: Describe how cells function in a narrow range pf physical conditions, such as temperature and pH to perform life functions Human impact of ecosystems B3.4C: Examine the negative impacts of human activities B3.4d: Describe the greenhouse effect and list possible causes B3.4e: List the possible causes and consequences of global warming DNA/RNA and Protein Synthesis B4.1B: Explain that information is passed by genes that code for DNA, these genes produce proteins B4.2B: Recognize that every species has its own characteristic DNA sequence B4.2C: describe the structure and function of DNA B4.2D: Predict the consequences that changes in DNA composition of a particular gene may have on an organism B4.2f: Demonstrate how genetic information in DNA molecules provide instructions for assembling proteins B4.2g: Describe the process of replication, transcription and translation and how they relate to each other in molecular biology B4.4c: Explain how mutations in the DNA sequence of a gene may be silent or result in phenotypic change in an organisms and in its offspring Mendelian and Molecular Genetics: B4.2h: Recognize the genetic engineering techniques provide great potential and responsibilities B4.4a: Describe how inserting, deleting or substituting DNA segments can alter a gen Lesson Overview: Students will investigate how the food they eat and its production effect the global climate. They will be introduced to the importance of bioenergy, our energy issues, the impact of those issues, and possible solutions. Students will investigate how changes in DNA can aid in producing plants that have higher levels of cellulose, which is important in producing ethanol. Lesson Core The Guiding Question: Materials and Equipment Needed: 1. Day 1: Greener Diet Article “Greener Diet” article http:www.sciencenewsforkids.org/articles/20090225?Note2.asp 2. Day 2-3: Bioenergy in the classroom Powerpoint- to be revised and attached at a later date 3. Day 4: Wheat Germ DNA Extraction Lab wheat germ- I level teaspoon liquid detergen- 1 ml Ethyl Alcohol (95%)- 15 ml (COLD) on Ice 50o – 60o Celsius tap water – 20 ml Hot plate with Beaker of Tap Water Thermometer 2 - 50 ml beakers 1 - Graduated cylinder (large) Glass stirring rod for stirring mixture Paper towel or Eye dropper – may be needed to remove foam Paper clip hook or wooden stick or spaghetti for collecting DNA 4. Day 2-3: Cell Wall Recipe Strips of construction paper (3 different colors) DNA strips (included in handouts) Scissors Glue DNA decoder (included in handouts) Poster board or large paper Safety precautions: Ethyl and isopropyl alcohol, 95%, are flammable and dangerous fire risks; keep from flame and sources of ignition. Both alcohols are also toxic by ingestion. Chemical splash goggles are advised whenever heat and glassware are used. Advanced Preparation Obtain wheat germ from health food store or many supermarkets Background Information for Teachers: Lesson adapted from: US Department of Energy. “Cell Wall Recipe: A lesson in Biofuels”. Author: Daniel Steever. Owner: National Renewable Energy Laboratory In these activities, students will investigate how changes in the DNA sequence that codes for cell wall formation can have a favorable outcome in producing plants that have higher levels of cellulose than the parent plant. It is the yield of cellulose that is most important in the production of ethanol, and the greater the amount of cellulose there is within in the cell wall, the greater the amount of ethanol that can be produced. To engage students, the first part of this lesson has students participating in a discovery activity where they will extract DNA from wheat germ. Following this, students will be given 3 strips of paper at random with different symbols on them; these strips are the DNA strands. While each strip has four symbols, only three symbols represent a gene (a codon, to be specific) and students will read the strips from left to right. By having four symbols per strip, students will have a variety of possible combinations as they lay out their strips to be decoded. Students will look at the key provided and build their cell walls based on the genetic code they were given. Students can make adjustments in their code if they have a fatal mutation or they did not get a gene for cellulose, lignin, or hemicellulose. Once students have built their cell walls they will evaluate the codes that would be most favorable in producing cell walls with a high percentage of cellulose and low percentages of lignin and hemicellulose. This module can be used as part of a whole unit or as an activity in understanding cell wall structure and function, DNA and genetics, evolution, technology, or science and society. Engage: Students will begin by reading the article “Greener Diet”, by Stephen Ornes from Science News forKids Feb 25, 2009. The article reports on new studies by scientists attending the American Association for the Advancement of Science in Chicago, Illinois, which show how food and its production can affect the planet and its warming climate. Researchers have warned that too much eating of meat can help make the planet warmer and put off too much carbon dioxide which is considered as a greenhouse gas. It affirms that eating vegetables like potatoes can help in easing the release of carbon dioxide to the atmosphere. Students will use a Writing in Science strategy to write a scientific explanation that identifies the claim made by the author. Students will indicate whether the claim is valid or not and support their reasoning with at least 3 pieces of supporting evidence. Should people eat less meat to help the environment? Class discussion will follow- key points will be recorded on large post it chart paperto be posted around the room and referred to/added to throughout the unit. Building on prior knowledge: Questions that the teacher might ask to assess students’ prior knowledge. Pre-teaching: Students should be familiar with the following vocabulary: Biofuel Biomass Cell DNA Enzyme Ethanol Genetics Hemicellulose Lignin Cellulose Fermentation Modification Cell wall Gene Mutation Students will build on ideas from previous units such as Mendelian Genetics, DNA, RNA and Proteing synthesis as well as Cells. A powerpoint will be available (in the resource section) reviewing the above vocabulary, as well as reviewing some basic concepts and introducing students to biofuels Biomass referes to any organic substance and can range from vegetables or trees to solid wastes such as paper and food based trash. The biomass can be converted to fuel by 2 main processes: biological conversion and thermochemical conversion. Below is a diagram that highlights major steps to fuel conversion: Biomass Biological Conversion Thermochemical conversion Pretreatment (acid hydrolysis) Enzymes Sugars for fermentation Pyrolysis (Upgrade) Gasification (Heat) Electricity Catalyst Fuel In biological conversion, the biomass is first treated using acid hydrolysis. The purpose of this step is to break up the lignin and hemicellulose within the cell walls, which interfere with the enzymes' ability to work on the cellulose. The enzymes break up the cellulose into sugars that can be used in fermentation. After fermentation the ethanol produced is distilled and can be used as fuel. In a thermochemical conversion, the biomass can be gasified or used in pyrolysis. Gasification creates heat that can be used to generate electricity or heat a home. Pyrolysis requires burning at high temperatures and pressure in the absence of oxygen. The product then needs to be upgraded to a more useful fuel. This activity looks at ways scientists are trying to “improve” the biomass in organisms such as corn, switch grass and other plants. Scientists have mapped the genome of maize (corn plants) and are genetically modifying the maize such that the cell wall contains higher amounts of cellulose than they have in the past. The challenge that scientists face is figuring out what genes are involved in producing a cellulose-rich wall and how they can create a healthy plant with this high cellulose wall and a reduction in lignin and hemicellulose. Explore: Lesson adapted from: US Department of Energy. “Cell Wall Recipe: A lesson in Biofuels”. Author: Daniel Steever. Owner: National Renewable Energy Laboratory AND http://docs.google.com/viewer?a=v&q=cache:BSwC8mfmDCkJ:hs.hpisd.org/uploads/45/f100873.doc+d na+in+wheat+germ+extraction+lab&hl=en&gl=us&pid=bl&srcid=ADGEESjwrxqoDztIVagMgynEd4Eg pG67MRY5sZuZLNumVnbjjo1UQEEn6Q-gyta8VdQYs4JFJeiDY-Q6Vca1iQHStBE0pWKgU3OcJRxDFcpghGKjROeUH5KbEY-5TZyUgadLsiEwaET&sig=AHIEtbQJ6cywRUrFxEwYNWHyd1EGnH2gA&pli=1 Wheat Germ DNA Extraction Lab Background: Remember that the four basic biological molecules that make up cells are nucleic acids, proteins, carbohydrates, and lipids. We can actually separate these molecules using regular household products. Our task for today is to extract DNA from the nucleus of wheat germ cells. Sounds tricky, but in fact if we follow the procedure carefully we can do this. We will be using a combination of household products to accomplish this. We will be using hot water to speed up reactions and to assist in breaking up the biological molecules. We will also be using a mild soap (Dawn or Ivory) to break up membranes. Remember that membranes are made of lipids, commonly called fat, and Dawn “cuts grease out of your way.” Unfortunately, we do not have a centrifuge in the classroom to “spin down” heavy molecules such as proteins and carbohydrates so we will use a 70% mixture of rubbing alcohol to separate the nucleic acids from the solution. The alcohol will create a precipitate with the DNA and after about 5 minutes the precipitate will float on top bringing the DNA to the surface. The DNA will appear white and stringy. So why would we want to do such a thing? Well DNA extraction is the first step to DNA “finger printing” or just about anything else involving DNA experimentation. HOW DOES IT WORK? DNA is present in all living things from bacteria to plants to animals. In animals, it is found in almost all cell types: cheek, muscles, reproductive cells, hair roots, -- anything with a nucleus. DNA is NOT found in Red blood cells because they lack nuclei. White blood cells do have a nucleus. DNA in a cell is about 100,000 times as long as the cell itself. However, DNA only takes up about 10% of the cell's volume. How can this be? This is because the DNA molecules fold themselves many times to pack themselves in the cell's nucleus. Each chromosome contains a single immense molecule of DNA that, in humans, has a length of up to 12 centimeters when stretched out! (look at 12 cm on ruler) As a matter of fact, all the DNA in one human cell (on all 46 chromosomes) is about two meters long, yet fits into a cell nucleus which is 2-3 micrometers (that's .000002 meters wide!). Yet, the DNA must still be in such a state as to allow for enzymes to replicate the molecule or initiate the production of a protein. The 23 pairs of human chromosomes are estimated to include about 100,000 genes. WHEAT GERM Wheat germ comes from wheat seeds. The “germ” is the embryo, which is the part of the seed that can grow into a new wheat plant. When wheat seeds are milled into white flour, the wheat germ and wheat bran are removed, leaving only starch. Wheat germ contains many nutrients while wheat bran consists of fiber. Whole-wheat flour contains all parts of the wheat seed and is therefore more nutritious than white flour while also providing important fiber for digestion. CHEEK CELLS Cheek cells come from the inner lining of mouth or the check. These cells are routinely shed and replaced by new cells. As the old cells die, they accumulate in the saliva in the mouth and can easily be collected by using mouthwash. One might say “Spit Happens”. ONION CELLS An onion is used because it has a low starch content, which allows DNA to be seen. The walls of onion cells are made of cellulose, which is a polysaccharide made of glucose. Cellulose provides a tough barrier that protects the cell. In order to examine the contents of a plant cell,blending helps to burst open the cell's walls and release contents. Onion cells also have membranes that envelop their contents. Cell membranes are made of a double layer of lipids that allow the movement and transfer of certain ions and substances in and out of the cell. Breaking down a cell's membrane allows you examine the contents of the cell. Detergents contain chemical compounds that can break down cell membranes. Water temperature The heat softens the phospholipids (fats) in the membranes that surround the cell and the nucleus. It also inactivates (denatures) the deoxyribonuclease enzymes (Dnase) which, if present, would cut the DNA into such small fragments that it would not be visible. Denatured enzymes and DNA unravel, loose their shape, and thus become inactive. Enzymes denature at 60°C and DNA denatures at 80°C. Detergent Detergent contains sodium laurel sulfate, which cleans dishes by removing fats and proteins. It acts the same way in the DNA extraction, pulling apart the fats (lipids) and proteins that make up the membranes surrounding the cell and the nucleus. Once these membranes are broken apart, the DNA is released from the cell. Soap molecules and grease molecules are made of two parts: Hydrophilic heads: which LIKE water and Hydrophobic tails which HATE water Both soap and grease molecules organize themselves in bubbles (spheres) with heads outside to face the water and tails inside to hide from the water. When soap comes close to grease, it captures it, forming a greasy soapy ball: A cell’s membrane has two layers of lipid (fat) molecules with proteins between them: When detergent comes close to cell, it captures the lipids & proteins & releases DNA: Alcohol The DNA released from the cell nucleus is dissolved in the water/detergent/wheat germ solution and cannot be seen. DNA precipitates out of solution in alcohol, where it can be seen. Besides allowing us to see the DNA, the alcohol separates the DNA from the other cell components, which are left behind in the water solution. The alcohol also causes gases dissolved in the water to be released, which may be observed as small bubbles. Meat Tenderizer : acts as an enzyme to cut proteins just like a pair of scissors. The DNA in the nucleus of the cell is molded, folded, and protected by proteins. So, the enzyme (papain) cuts the proteins away from the DNA. Papain also helps break down DNAase, an enzyme that breaks down DNA) (Not used in all of the DNA extractions) DNA Extraction from Wheat Germ Materials Raw wheat germ – 1 level teaspoon Liquid detergent - 1 ml Ethyl Alcohol (95%) – 15 ml (COLD) on Ice 50o – 60o Celsius tap water – 20 ml Hot plate with Beaker of Tap Water Thermometer 2 - 50 ml beakers 1 - Graduated cylinder (large) Glass stirring rod for stirring mixture Paper towel or Eye dropper – may be needed to remove foam Paper clip hook or wooden stick or spaghetti for collecting DNA PROCEDURE: 1. Place 1 LEVEL teaspoon of raw wheat germ in a 50 ml beaker 2. Add 20 ml of hot (50-60 °C) tap water and mix constantly for 3 minutes. 3. Add 1 ml or (15 -18 drops) of detergent and mix gently for 5 minutes. DO NOT MAKE FOAM 4. Use a piece of paper towel or an eyedropper to remove any foam from the top of the solution. 5. BEFORE adding the alcohol, POUR the water/detergent solution into a clean beaker, leaving behind the wheat germ. 6. Tilt beaker with the water/detergent solution at an angle. SLOWLY pour 15 ml of COLD alcohol down the side so that it forms a layer on top of the water/wheat germ/detergent solution. Do not mix the two layers together. (DNA precipitates at The water-alcohol interface (the boundary between the water and the alcohol). Therefore, it is crucial to pour the alcohol very slowly so that it forms a layer on top of the water solution. If the alcohol mixes with the water, it will become too dilute and the DNA will not precipitate.) 7. Let the beaker sit for a few minutes. White, stringy, filmy DNA will begin to appear where the water and alcohol meet. You will usually see DNA precipitating from the solution at the water-alcohol interface as soon as you pour in the alcohol. If you let the preparation sit for 15 minutes or so, the DNA will float to the top of the alcohol. 8. You can usually get more DNA to precipitate from the solution by using one of the DNA-collecting tools (paper clip hook) OR spaghetti to gently lift the water solution up into the alcohol. This allows more DNA to come in contact with the alcohol and precipitate. Then use paper clip hook or a wooden stick or spaghetti to collect the DNA. 9. Place DNA on paper towel and air dry. FEEL IT. 0R 10. If time permits, place a small sample of DNA on a slide with coverslip; look at it with microscope. Be sure to share results with all lab partners!!! Explain: DNA EXTRACTION Group Names: ______________________ _____________________ ______________________ Name________________ Table#_____ Date________________ Per._____ Teach sign READ NOTES ON BACK 1. List three things available to you that you might use for a DNA source besides wheat germ, onion, cheek cells or split peas. 2. List three things that would not be a DNA source. 3. What is the role/purpose of DNA in a cell? 4. a. Explain how DNA is contained in a cell. b. Why does DNA extraction need to be performed in order to obtain DNA? 5. a. Describe what you saw happening in the beaker. b. Describe the product that was obtained. 6. What is an Enzyme? 7. Why did you use detergent in the procedure, and how does it work? (see notes on back) 8. What possible benefits might be obtained by the ability to isolate the DNA of any organism? 9. Which “ingredient” (besides wheat germ,cheek cells, onions, or peas) do you think might have the most effect on the amount of DNA you extract? __________________________________________ 10. How can you test your Hypothesis? Describe an experiment to test your hypothesis. Elaboration: Results Questions: 1. What does the salt do? (gatorade) (Salt provides the DNA with a favorable environment; it contributes positively charged atoms that neutralize the normal negative charge of DNA.) 2. What does the blender do? (help break down the cell walls) 3. When you mix the blended cell source with the soap, what is happening? (In the experiment, the enzymes in the soap are breaking down the lipid molecules of the cell and nuclear membranes, releasing the contents of the cell, including the DNA. These enzymes in the soap are what break down grease while washing dishes.) 4. What does the alcohol do? Why does the DNA rise to the top after adding alcohol? (DNA will not dissolve in this alcohol, so the DNA comes out of the solution, or precipitates. It is less dense than water or cell scum--which is what settles to the bottom of the glass--so it floats up into the alcohol layer, where you see it as a snotty, string-like substance, with small bubbles formed on it.) 5. If you try a seed food such as peas, there will be more protein residue in the liquid. Why? (Because protein is stored in them for the nutrition of the new plant.) 6. Why can’t you see the double helix? (It is too small to be seen with the naked eye. What you extracted is millions of strands of DNA.) 7. What part of the cell did the DNA come from? (99% is from the nucleus.) BONUS: 1. If you did the experiment with both plant and animal cells, how would their DNA compare? Evaluate: Material List: Strips of construction paper (3 different colors), glue, DNA strips (included below), poster board or butcher paper, DNA decoder (included), scissors DNA Strips: Main Activities: 1. Engage students on day 1 by doing the Wheat Germ DNA Extraction Lab. 2. Mini-lecture on biofuels and plant biology (Plant biology should be a review.) 3. Tell students that they are genetic engineers and that they will be constructing a cell wall based on a genetic code they have picked out with the DNA strips. 4. Distribute the DNA decoder sheet. 5. Have DNA strips cut out and placed in some sort of container and mix the strips up such that the strips will be picked buy students randomly. 6. Have students choose 3 DNA strips from the container at random. 7. Students will now arrange the 3 strips to form a chain such that the 3 strips give 12 symbols in a row. 8. Tell students that every 3 symbols represents a gene and to use the decoder to figure out what their DNA strand codes for. 9. Remind students what a genetic mutation is and review dominant and recessive genes. Example: Gene #1 Low lignin Gene #2 High Cellulose Gene #3 Gene #4 Medium Hemicellulose Low Lignin 10. Students can arrange their strips in anyway they wish. The target is to get low lignin and hemicellulose and high cellulose. The first time it is fine if the student does not get the desired combination, but students should work on arranging their DNA in the best possible combination. You may allow students to switch out strips as many times as they wish to get the desired outcome. However, the desired outcome is statistically based and the student may spend a great deal of time trying to get the “correct” combination. Issues: If the student can’t get three genes for the three components of a cell wall they must “throw out” one strip and replace it with something different from the DNA container and then find another combination. If the student gets a fatal mutation they must rearrange their strips or replace it with another. (Many mutations scientists create to improve cell walls are fatal.) If the student gets 2 genes for the same component (lignin, hemicellulose, or cellulose) the student uses the gene that is most desirable. 11. Have students “build” their cell walls using strips of construction paper. Students should glue the strips down in a way that cellulose is glued first, hemicellulose second, and lignin third. Students should use a crisscross pattern so that all three layers are visible. The number of strips for low, medium, and high are determined by the teacher. Suggestions: 3 strips = low, 6 = medium, 9 = high. 12. Now have students “improve” their cell wall buy changing the code. They can draw the new code or pick out the same strips as before, cut out individual symbols and glue them down as their new code. Repeat step 10 for the new code. 13. Students can display their work; do a write up, etc. Lesson Closure: Assessment: Students will be asked to present their “cell walls” to the teacher one on one as a “show and tell”. Students will be asked to articulate the following: 1. What are the 3 principle components of plant cell walls? 2. How did you read your genetic code? Did you have to manipulate anything? 3. What was the ideal composition of the cell wall? 4. Why are high amounts of cellulose desirable? 5. What genetic modifications did you make to improve your cell wall? 6. Describe the process of converting biomass into ethanol in 5 steps. 7. What is a genetically modified organism? 8. How can biofuels help our society and environment? Lesson Extension Assessment Options: Additional Resources: 1. Lesson adapted from: US Department of Energy. “Cell Wall Recipe: A lesson in Biofuels”. Author: Daniel Steever. Owner: National Renewable Energy Laboratory 2. http://docs.google.com/viewer?a=v&q=cache:BSwC8mfmDCkJ:hs.hpisd.org/uploads/45/f100 873.doc+dna+in+wheat+germ+extraction+lab&hl=en&gl=us&pid=bl&srcid=ADGEESjwrxq oDztIVagMgynEd4EgpG67MRY5sZuZLNumVnbjjo1UQEEn6Q-gyta8VdQYs4JFJeiDYQ6Vca1iQHStBE0pWKgU3OcJ-RxDFcpghGKjROeUH5KbEY5TZyUgadLsiEwaET&sig=AHIEtbQJ6cywRUrFxE-wYNWHyd1EGnH2gA&pli=1 ***How to insert powerpoint