Picture Essay: Recombinant DNA
Lesson 3 of 6
Objective: Students will be able to explain (make sense of) the technical process leading to the creation of GMOs (via “recombinant DNA”).
Note: I recommend that you first check out this resource in order to get the most out of this lesson!
In high school I took several drafting classes and, for a while, I had hoped to become an architect. With respect to planning instruction and teaching, I feel that I can still live out the detailed approach to building something intricate and complex even though the product is a lesson rather than a certain "built environment".
The lesson-planning document that I uploaded to this section is a comprehensive overview of how I approach lesson planning. This template includes the "Big Three" aspects of the NGSS standards: Disciplinary Core Ideas, Crosscutting Concepts, and Science Practices. Of course, there are many other worthy learning goals, skills, instructional strategies, and assessments that can be integrated into a class session. I don't feel compelled to check every box but, rather, use it as a guide to consider various options and tailor the lesson in light of these.
Generally speaking students will...
1. understand that genetic material can be transferred from one organism to another by the tools of biotechnology.
2. know that only small parts of the DNA molecule need to be transferred to make large (phenotypic) effects.
Specifically students will…
1. understand that, through genetic engineering, foreign DNA can be introduced into a (host) organism. Furthermore, this foreign gene is then transcribed and translated as part of the host’s genome (DNA code) that can then produce the foreign protein.
2. describe a gene as a segment of DNA that codes for a certain protein (amino acid chain).
3. explain (make sense of) the process leading to the creation of “recombinant DNA” in a visual and verbal format.
I hope you get some value from my work!
Direct students to review Enduring Understanding #1 and 2 found in their unit map. This document is very important to the progression of instruction in my class. It really serves as the skeleton for a given unit and it is meant to be a guide for what students will be learning (formatively speaking) as well as a look in the proverbial "rear view mirror" when the unit is wrapping up. I use it as a study guide as well in preparation for the summative assessment at the end of the unit.
Then prompt students to self-assess their understanding of Goal 5.1.4 & 5 from the Unit Map. Note that this is an extension and deepening of the Recombinant DNA Foldable lesson.
Teaching Challenge: How do I support students to persevere and grapple with complex tasks? In a word: Scaffolding. Over. Multiple. Days.
Teaching Challenge: How do I increase/improve my students' use of appropriate and precise science vocabulary?
Clearly, the business of creating GMOs is heady stuff. To make sense of it (either through discussion or writing) requires a slow-down approach to make sure students don't get left at the proverbial bus stop as the bus rumbles down the street.
Step #1 occurred with wrapping our collective minds around the notion of blending traits from separate organisms into a single being, as it were. (TC #1)
Next, students worked to describe the nature of recombinant DNA. (TC#2)
Then, students were challenged to dive more deeply into the process as new vocabulary has been added such as plasmid, vector, chromosome, desired gene, etc. This lesson requires students to put together the various pieces in order to explain the technical process in a more sophisticated manner. (TC #1 & 2)
This is about as complicated as things will get so this activity serves as a benchmark for checking for understanding.
Here is how I facilitate things. Present the assignment and discuss the stages of the task: label features of diagram (using the word bank and yellow speech bubbles), identify each part of the diagram using the labeled speech bubbles, and then explain the sequence of steps in as coherent manner as possible.
Note that there are three distinct challenges (steps) to creating a GMO. See graphic.
- Splicing the DNA of two separate species. In this case, human and bacterial.
- Inserting the recombinant DNA into a separate (recipient) organism (a different bacterium in this case).
- Coaxing the bacteria to produce the human protein product.
All steps require precise and technical knowledge, skill, and technology to be successful in an actual lab setting despite the seeming complexity of it all.
Here is my version of the answer key. Note that the placement of some of the labels can differ from this key and still be accurate.
Parking Lot: Prompt students to jot down a question or unclear idea on a Post-It note and place it on the Parking Lot space (essentially a blank bulletin board space clearly visible and accessible to all). Using this feedback, I can distill the main ideas that need rework and further explanation the next day.