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| Notes: Plant Pigmentation |
ROY G BIV
Organisms that use light to synthesize large molecules to store energy are known as photoautotrophs.
Light is electromagnetic energy, which is radiation, which is electromagnetic waves, which are disturbances in electrical and magnetic fields.
Photosynthetic Pigments in Plants |
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| chlorophyll (reflect
greens)
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carotenoids
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phycos
(absorb greens)
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| a = primary pigment b, c, d = chlorophyll accessory pigments |
reflect yellows and oranges are accessory pigments to chlorophyll |
phycoerythrines reflect reds and violets phycobillins reflect blues found moreso in vacuoles |
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Accessory Pigments absorb slightly different wavelengths of visible light and send them to chlorophyll a.
Absorption
The only photons absorbed are those whose energy is exactly the same as the Energy Difference (varies from one atom/molecule to another) between the ground state and the excited state of the molecule's electron(s); thus a particular compound absorbs only photons of corresponding wavelengths.
Photons are intangible--energy--but act like objects or particles.
Chlorophyll is the most effectively absorbs blue and red light (the colors most useful as energy).
Specific color absorption by Chlorophyll -a (blue-green)
Indigo, Violet, light Red
Specific color absorption by Chlorophyll -b (yellow-green)
Blue, little bit of Orange
Specific color absorption by Carotenoids
Blue to Indigo with a smaller amount of Violet
Absorption spectrum is a graph of wavelength v. pigment's light absorption.
Action spectrum is profile of rate of photosynthesis (oxygen release or carbon dioxide consumption measurements) v. wavelength.
A spectrophotometer measures the transmittance or absorbancy of a pigment for a given wavelength.
Next: "Photoexcitation."
Energy
Decreases