Learning Objectives

1. Students will be able to list the 4 nitrogenous bases associated with DNA.
2. Students will be able to “decode” a hypothetical strand of DNA.
3. Students will be able to list the 3 major building blocks of a cell wall.
4. Students will be able to articulate the structure of their cell walls.
5. Students will be able to create a flowchart illustrating ethanol production from planting through distillation in 5 steps.
6. Students will be able to improve their “cell wall” by making at least one genetic modification through collaboration with peers.
7. Students will be able to articulate 2 challenges facing scientists who are working on biofuels and 2 possible solutions.
8. Students will be able to articulate what a genetic modification is.

Teaching Process

Detailed instructions can be found in the attached lesson plan.

Teachers Notes

In this activity, 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. This activity is simple and, in my experience, has worked great in the 7th grade science classroom. 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.