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Since man first started raising crops, we have quested for stable varieties with high yield, no matter what the conditions may be. Our early ancestors developed many techniques such as cross breeding to develop some of our earliest crops. Humans have been seeking out plants that produced high yield fruit and grains, and nurturing specific varieties through selective breeding, until we developed the very crops we know today. Corn was once a small plant, which is today considered a weed, teosinte. Teosinte had very few grains on each fruiting body, and all grains had very hard outer seed cases that would protect the nutrition to be found inside. Through humans selecting varieties from the wild and cross breeding them by hand, we developed the many maize varieties we have built our civilization on. Today, we face an ever increasing challenge of producing more and more food for a growing human population. We must go back to our roots and continue to develop varieties, just as our ancestors before us, to meet this demand. Through the expanded biological understandings of genetics and new techniques of genetic modification we have to create varieties that increase yield, decrease herbicide and pesticide use, and ultimately grow more food. In this exercise students will learn more about the origins of plant varieties, and how we continue to develop new varieties by utilizing new technologies.
Science
Math
Ag Competencies: 018.Agriscience in Our World
Materials for each lab group:
Materials for assessment:
The E. coli strain used in this lab is non-pathogenic, meaning it will not directly cause illness in humans, but it is important to teach the students good sterile technique and safe disposal of bacteria or anything that could be contaminated.
To dispose of contaminated material Immerse all disposable pipettes, tubes, and loops that have come in contact with bacteria in 10% bleach solution for at least 20 minutes before draining, rinsing, and disposing of in the trash. Immediately after use of the pipette or loop, place it directly into the waste beaker. Remind them that these items are designed to be used one time only.
When you are finished with the lab, collect all petri dishes, open, and immerse in a 10% bleach solution to kill all bacteria. This can be easily accomplished by flooding all the plates with a few ml of the bleach solution. Allow materials to stand in bleach solution for 20 minutes or more. Drain excess solution, seal materials in a plastic bag, a large zip lock bag works well to contain any liquid that may seep from the plates. Place all bags containing the materials and double bag in trash bags then simply place in the trash for final disposal.
Length of Time for Preparation: 3-5 days
Day 1: Pour plates Day 2: Cure plates (room temp.) Day 3: Inoculate starter plates with E. coli and incubate Day 4: Complete transformation; begin incubation (overnight in incubator, or 2 days on lab table) Day 5: Review lab results
Length of Time for Classroom Teaching: 2-3 days
Day 1: Complete transformation; begin incubation (overnight in incubator, or 2 days on lab table) Day 2: Review lab results Part 1: Activating Prior Knowledge and Anticipatory Discussion
It is recommended to complete the Paper Plasmid Lab as an introductory activity. Also visit the lab for classroom discussion suggestions.
(Pre-Lab: 20-30 minutes and Lab: 45-60 minutes )
Complete the Bacterial Transformation Lab as outlined with the instructions from the Bio-Rad Laboratories, Inc. Transformation Kit – Quick Guide. Below, on (pg. S1-S2, you will find the pGLO Quick Guide for students. This visual reference should be utilized in the pre-lab with students.
Procedure for Pre-lab Each student should have a printed copy of the pGLO Quick Guide.
Procedure for Lab Follow the instructions on the pGLO Quick Guide that you have highlighted. It is important to make sure all students have done the pre-lab before you complete the actual lab, as there are time sensitive elements that must be followed correctly for the best results. Refer to the pGLO Quick Guide handout from Bio-Rad for lab instructions.
Refer to the pGLO Student Sheet (pg. S3-S4) for post-lab activity. After the incubation of the transformed plates, you will have 4 observations to make. There are guiding assessment questions to answer on the following document as well as a place to record data. This can be printed or can be sketched into a science journal.
Do not forget to use this as an opportunity to expand student ideas about how we would then use these genes. In corn, one of the first transgenic varieties contained a gene from the bacteria, Bacillus thuringiensis (Bt), which causes the plant to create a toxin which stops insects from eating the plant and killed any insect that ingested the plant. This allowed the newly transformed plant to be less susceptible to damage from insects; thus increasing yield overall and decreasing the use of additional pesticides. As an extension activity, pose the following questions:
Bacterial Transformation Lab In order for students to achieve transformation it is critical that they work through the lab using the precise steps and times outlined in the pGLO Quick Guide. If they have completed the lab correctly, one plate and one plate only should have glowing bacteria, the + LB/Amp/Ara. If their results do not show this, allow students the opportunity to analyze where their mistake may have taken place and determine what they would do differently if they could complete the procedure again.
Overall Assessment Written or oral assessments on how and why this transformation lab is considered genetic modification is a fantastic way to assess the overall understanding of the students’ knowledge. This can be done via a presentation or through a paper explaining each step in the process, the creation of plasmids, the transformation process, and how it relates to the overall goals of food stability. While performing assessments, refer to NSTA’s Lab Report Rubric (pg. T8).
Almost all new seed varieties being created today have some level of biotechnology involved in their development. From plant tissue culturing to genomic analysis and alteration, all rely on the primary skills of sterile technique and basic understanding of the genetic code. Several different careers in agriculture are fundamental in the development of new varieties of crops: botanists, horticulturalists, biochemists, biological engineers, climatologist, ecologists, food scientists, geneticist, microbiologists, plant pathologist, and an army of lab technicians are all involved in the development of each and every variety.
Any educator electing to perform demonstrations is expected to follow NSTA Minimum Safety Practices and Regulations for Demonstrations, Experiments, and Workshops, which are available at https://static.nsta.org/pdfs/MinimumSafetyPracticesAndRegulations.pdf, as well as all school policies and rules and all state and federal laws, regulations, codes and professional standards. Educators are responsible for abiding appropriate legal standards and better professional practices under a duty of care to make laboratories and demonstrations in and out of the classroom as safe as possible. If in doubt, do not perform the demonstrations.
This lesson is the work product of the Kansas Corn Commission. Our lessons are written in collaboration with Kansas teachers for use in the classroom. Teachers may copy and share this curriculum. Use of this product for commercial or promotional use is prohibited without express permission of Kansas Corn.
As the need to produce more food with less resources grows, it is important that future generations have a better understanding of agriculture and how corn farming and agriculture fit into our daily lives. That’s why the Kansas Corn STEM program provides lessons to teach science through the lens of corn. We are committed to providing free materials and training to support educators.
