Weeks 34-35 – Toxin LD50 Calculations

For the final research part of the Toxin Research Project, it’s time to answer the question: how much is too much?  To answer that question, you need to research how much of your toxin is in a “standard dose” of your toxin.  “Standard dose” can be hard to find, and is often provided as a range.  For example, a “standard dose” of caffeine might be 100-200 mg per “dose” with a dose being an 8 ounce cup of coffee or a 12 ounce can of soda.  In that case, split the difference and use 150 mg as the standard dose for caffeine.  Buckle up – this is often the hardest part of this project.  Be persistent!  If “standard dose” doesn’t work as a search term, try “amount per serving” and see if that works.

Instructions for Slide 3:

  • Add Slide 3 to your Google Slides deck and title it “Toxin LD50 Calculations”
  • On Slide 3, answer the following:
    • Click the PubChem link to your toxin from Slide 1
    • Locate the molecular weight (synonym for molar mass) in PubChem and enter it on Slide 3
    • Using the molar mass and the LD50 (from Slide 1), calculate the lethal dose of the toxin for humans of three different masses and show your calculation work on the slide:
      • 10 kg
      • 30 kg
      • 75 kg
    • How many “standard doses” of the toxin does it take to reach the lethal dose for a person of mass 10 kg?  30 kg?  75 kg?

Here’s a video of my efforts to determine the “standard dose” of capsaicin per jalapeno pepper:

Need help bring these concepts together?  From the video above, we learned that the average jalapeño contains 2.24 mg of capsaicin.  Here is an example calculation for how many jalapeños a 75 kg person would have to eat to reach the lethal dose for capsaicin (identified in Slide 1 as 47.2 mg/kg):

75 kg x (47.2 mg capsaicin / 1 kg) x (1 jalapeños / 2.24 mg capcaisin) = 1580 jalapeños

When finished with Slide 4, return to Weeks 34-35 – How Much Is Too Much? and continue working.

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