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 paper- to 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 / Cellulose / Cell wallDNA / Enzyme / Ethanol / Fermentation / Gene
Genetics / Hemicellulose / Lignin / Modification / 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) Gasification
(Heat)
Pyrolysis
(Upgrade)
Enzymes
Electricity Catalyst
Sugars for
fermentation
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+dna+in+wheat+germ+extraction+lab&hl=en&gl=us&pid=bl&srcid=ADGEESjwrxqoDztIVagMgynEd4EgpG67MRY5sZuZLNumVnbjjo1UQEEn6Q-gyta8VdQYs4JFJeiDY-Q6Vca1iQHStBE0pWKgU3OcJ-RxDFcpghGKjROeUH5KbEY-5TZyUgadLsiEwaET&sig=AHIEtbQJ6cywRUrFxE-wYNWHyd1EGnH2gA&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.