|Property of Light Wave||Perceived by Humans as||Units of Measure||Range Perceived|
|Wavelength||Color||nanometers (nm)||400-700 nm|
|Amplitude||Brightness/Intensity||footcandles (fc)||0 - 10,000 fc|
|What is white light?||All visible wavelengths of light together|
|In white light a leaf appears green because:|
|it reflects||Green light|
|and absorbs||All other wavelengths of light|
Compare and contrast etiolated growth in darkness and normal growth in light (hint: your lab exercise should assist you!)
Preserving Cotyledon Reserves
Light Green Stem
Using Up Cotyledon Reserves
|Color of light perceived||Blue|
|Where light is perceived||Tip (apex)|
|Hormone produced at perception site||IAA (auxin)|
|Side of plant accumulating the hormone||Shaded|
|Side of plant with accelerated growth||Shaded|
|Direction of curvature growth||Toward Light|
Provide the 4th grade (one-step) reaction diagram for photosynthesis:
Now dissect this into the 8th grade (two-step) reaction diagrams for photosynthesis:
Light Independent Reactions
Sketch a graph of how the rate of photosynthesis relates to the color of light. Be sure to label your axes with both name and some measurement scale with units.
Sketch another graph, this time showing how the rate of photosynthesis and respiration relate to the intensity of light. Be sure to label your axes with both name and some measurement scale with units.
The intensity of light where the two curves cross is called the _____________________________.
What is happening when a plant is kept at an intensity...
higher than this point?____________________________________
lower than this point?____________________________________
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