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Introductory Biology

  • This collage contains original images taken by the course instructor. The images show a microscopic view of stomata on the underside of a Brassica rapa leaf (A), B. rapa plants in their growth trays (B), a flowering B. rapa plant (C), and different concentrations of foliar protein (D). Photos edited via Microsoft Windows Photo Editor and Phototastic Collage Maker.

    A flexible, multi-week approach to plant biology - How will plants respond to higher levels of CO2?

    Learning Objectives
    Students will be able to:
    • Apply findings from each week's lesson to make predictions and informed hypotheses about the next week's lesson.
    • Keep a detailed laboratory notebook.
    • Write and peer-edit the sections of a scientific paper, and collaboratively write an entire lab report in the form of a scientific research paper.
    • Search for, find, and read scientific research papers.
    • Work together as a team to conduct experiments.
    • Connect findings and ideas from each week's lesson to get a broader understanding of how plants will respond to higher levels of CO2 (e.g., stomatal density, photosynthetic/respiratory rates, foliar protein concentrations, growth, and resource allocation).
    Note: Additional, more specific objectives are included with each of the four lessons (Supporting Files S1-S4)
  • Enzymatic avocado browning is driven by polyphenol oxidase. Mashed avocado pulp is bright green but turns dark brown over the course of two hours at room temperature in the presence of air and salt. This reaction can be accelerated or inhibited by more than 20 different testable reagents, allowing students to explore experimental design.

    The Avocado Lab: An Inquiry-Driven Exploration of an Enzymatic Browning Reaction

    Learning Objectives
    Students will be able to:
    • develop a testable research question and supportive hypothesis regarding the browning of damaged avocado flesh caused by the activity of avocado polyphenol oxidase (aPPO).
    • design and execute a well-controlled experiment to test aPPO hypotheses.
    • evaluate qualitative enzyme activity data.
    • create a figure and legend to present qualitative data that tests multiple hypotheses and variables.
    • search for and correctly cite primary literature to support or refute hypotheses.
    • know the role of reducing reagents, pH, chelators, and temperature in reactions catalyzed by aPPO.
    • explain why the effects of salt and detergent differ for aPPO experiments conducted in situ
    • (in mashed avocado flesh) as compared to in vitro (on purified protein).
    • discuss how substrate and cofactor availability affect aPPO reactions.
    • describe how endogenous subcellular organization restricts aPPO reactions in a healthy avocado.
    • evaluate food handling practices for fruits expressing PPO.