Christopher Chirdon Project 1 – Selecting and Using Multiple Modes of Instruction Project Introduction The following project stems from a niche I identified while trying to teach students about enzyme activity and kinetics. The topic seems straightforward to me but is clearly alien to my students; a recipe for disaster. After designing an inquiry based lab, several presentations, discussions, and some conceptual models, I determined that the intricacies were beyond many of the students. My solution is technological. The background should be discussed ahead of time and some the basic theories hashed out. Technology comes into play in the form of a virtual lab experience. After the groundbreaking into enzymatic activity they will use ZymeTime to observe at a molecular level the activity of enzymes and substrates. ZymeTime software requires a beefy computer and 3D rendering card to work properly. Minimum system requirements would be in the P4 1400 AMD Athlon XP 1800 Range and require an NVidia GeForce 5800 series card to run. The ZubSub is the vehicle students use to navigate the worlds. They will witness enzymatic activity in this manner: · Choice of “worlds” to explore reactions in o CellWorld – Thicker medium enhances ‘diffusive’ characteristics. The horizon is a pinkish space implying the inside of a cell. Cell organelles are present but cannot be interacted with. o TubeWorld – All takes place inside the bottom 1/3 of a test tube. Has a bluish hue to it. Ceiling is the surface of the liquid. · Enzymes and substrates are rendered in 3D hardware accelerated form · All particles are space-filled spheres with muted color schemes · Students can control the view of their camera to take a wide-angle shot and see all the bits whizzing around. · They can also click on any particle and “follow” it or “track it” in real time. · They can move around objects. · They can speed up or slow down time in increments of 2x · Bumping can be turned on or off. Default is off. When substrates or enzymes hit the ZubSub (the vehicle students explore the worlds in) students hear a thud in 3D stereo. · ZubSub Controls: o Usually the mouse is simply a mouse and can be used to click buttons on the ZubSub dashboard to change the external environment’s factors. On the dashboard: § Temperature § enzyme concentration § substrate concentration § allosteric inhibitor concentration (and on/off) § competitive inhibitor concentration § feedback inhibition on/off § The Graph-O-Matic button. A transparent HUD graph can be brought up on the viewing window that shows some factor or factors as a function of time. The vertical axis may be selected to be one (or several) of many factors. o ZubSub movement is controlled by using the mouse and the now standard video game evolved asdw & mouse: § Keyboard · A = strafe left · S = slow down · D = strafe left · W = acc forward § Mouse · Left is turn left · Right is turn right · Mouse up = pitch up · Mouse Down = pitch down § Hold SHIFT key (pinkie) to use mouse to press buttons on the dashboard. o The ZubSub comes to a stop on its own due to the fact that the atmosphere is fluid (it does so exponentially, though)
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The ZubSub has a characteristic rocking motion while in
motion. Part 1, Lesson plan
Big Idea Students historically grapple with the concepts involved with enzyme kinetics and dynamics. Because we cannot see enzymes, their action is very foreign, and seeing conformational changes during binding, action, and release is impossible. I think that I could have turned the entire chapter, a 3 week course on enzymes, into a one-week exploration and had all students at high levels of comprehension.
Objectives SWBAT
Standards Addressed
Procedure
Solicit ideas: “What is an enzyme?”
Develop ideas: “What do they do?” “How do they work?” “What do they look like”
Reassure students that they’ve probably never seen an enzyme itself, but they have interacted with them before. Anyone with contact lenses here? Discuss the role of enzymes at breaking down protein deposits on contacts. Who likes cheese? Discuss the role of rennet in cheesemaking. What are you taking notes on right now? Discuss the role of cellulase in the paper-making process. Define/discuss: Enzyme – Shape Active Site – Specificity Substrate Reactant Product Rate of reaction
Now, explain the ZubSub and the missions. Explain that there will be a series of missions. Each mission should be completed in its entirety before continuing onto the next mission.
Explain to students that they will work in groups of 3 for this activity. One will be the Pilot and the other the Recorder.
Mission 1: TubeWorld Simplicity Record the environmental variables of mission 1.
Press Play to begin the simulation.
Describe the enzyme molecule. Compare it to the substrate molecule.
Wait until all substrate has been converted into
Mission 2: TubeWorld Contemplating Concentration Start the level. This time, increase the starting concentration of enzyme. Note the difference between the graph from t=0 to t=30 seconds.
Now, reset the simulation to start point.
Increase the starting concentration of substrate by a factor of 10, restart the simulation, press play, and note the progression of the experiment.
Increase the starting concentration of substrate by a factor of 10 (so, 100 times the original), restart the simulation, press play, and note the progression of the experiment.
Mission 3: CellWorld Now we will explore the cellular matrix.
We will examine the activity of an enzyme present in the cellular matrix. However, this enzyme is inhibited by its end product. Watch what happens as the reaction progresses.
Press start and notice the rate of reaction.
How many molecules of enzyme are free to act on substrate at the beginning and at the end?
Will the reaction ever go to absolute completion? Explain.
Mission 4: CellWorld Danger! The cell has been injected with cyanide! Just like in spy movies cyanide is deadly. Press start and observe why it is deadly then explain.
Mission 5: Destroy the stain You are commander of the enzyme armada. A large protein-based grass stain has invaded your favorite t-shirt. Figure out how to get rid of this nasty blot on humanity.
The culmination of the mission will be to construct a report that describes how each of the factors affects the rate of reaction and to discuss it at a molecular level.
Assessment Have each team present a mission summary from the game. They must explain the important concepts involved in each level. Presentations need not be formal, but students should present an adequate amount of information.
Project 1 Reflection The more I designed this activity the more I became convinced that this is the way to teach enzyme concentrations. Though I think it would be great to follow up with a good lab, or possibly lead off with a good lab. This activity could lead to learners with highly intuitive concepts of enzyme reactions.
I chose to activate prior knowledge initially. Through discussing examples of enzyme activity I hoped to build a foundation of familiarity with the students. The students add experience to the information and I orchestrate it into a coherent picture. I then expand it in context of enzymes.
Next, I wanted to allow students to explore the software. It should be noted that much of the inquiry comes from the ZymeTime virtual lab. The fact that students get to do anything they want in the world helps them to try a great many experiments in a short amount of time. It’s through this interaction that they can figure out how enzymes work and what they’re used for. I envision that there would be a lesson generation portion of the software so that instructors could make their own explorations. In this way, new missions could be made, much the way DOOM and Quake have level generator mods that can be used to create new missions. The more I think about it the more I think that the “Descent” engine, with its naturally bobbing nature could be used to design most of the worlds.
As for responsibilities, students are responsible for, in many ways, making meaning out of the information on their own. Teachers would only be used to give nudges in the right direction playing classical constructivist “guide on the side” role.
Ultimately this entire lesson could be done without the technology, but it would take a heck of a lot longer, be relatively boring, and not allow students to visualize what is going on. I believe that in a 30 minute period, students could do 10 – 15 different experiments using the ZymeTime engine, whereas they could only do 2-5 runs of actual physical enzyme experiments such as H2O2 catalase labs. |