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Enzyme Kinetics Explorer

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About This MicroSim

This simulation plots the Michaelis-Menten relationship between substrate concentration [S] and reaction velocity v. Students can change Vmax, adjust Km, drag or autoplay the on-curve probe to read precise coordinates, and visualize how competitive versus noncompetitive inhibitors reshape the curve. Stage prompts in the right panel guide learners from interpreting the labeled asymptotes to comparing overlay curves.

How to Use

  1. Set Vmax and Km with the sliders while watching the dashed Vmax and Km references shift on the graph.
  2. Drag the blue probe dot along the curve (or let playback run) to read [S], v, and percentage of Vmax in real time.
  3. Turn on the inhibitor toggles and raise [Inhibitor] concentration to see competitive inhibitors shift Km right and noncompetitive inhibitors pull Vmax downward. Use Reset to return to the default kinetic profile.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

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<iframe src="https://dmccreary.github.io/biology/sims/enzyme-kinetics-explorer/main.html"
        height="450px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Grade Level

11-12 (AP/IB Biology)

Duration

15-20 minutes

Prerequisites

  • Ability to interpret coordinate graphs and read asymptotes
  • Prior exposure to enzyme function, Vmax, and Km
  • Basic algebra skills for ratios and percentage change

Activities

  1. Stage 1 - Baseline curve (5 min): Move the Vmax slider to see the horizontal asymptote rise, then adjust Km to watch the dashed Km line shift right and discuss what these changes mean for affinity.
  2. Stage 2 - Probe investigation (5 min): Drag the probe to several [S] values, record the matching velocities, and calculate when the reaction is operating at 50% Vmax or greater.
  3. Stage 3 - Inhibitor comparison (5-10 min): Activate each inhibitor, increase [Inhibitor], and explain why the competitive overlay shifts horizontally while the noncompetitive overlay lowers only Vmax.

Assessment

  • Students correctly state how changing Km or Vmax reshapes the Michaelis-Menten curve.
  • Learners use probe data to justify whether the reaction is saturated at a given [S].
  • Students compare screenshots or notes from inhibitor runs to explain how therapeutic inhibitors would alter enzyme behavior.

References

  1. Michaelis, L., & Menten, M. L. (1913). Die Kinetik der Invertinwirkung. Biochemische Zeitschrift.
  2. Campbell, N. A., & Reece, J. B. (2019). Campbell Biology (12th ed.). Pearson.