Chloroplasts II

• Chlorophyll

  Photosynthetic pigments
• Accessory Pigments

  • absorbs wavelengths of light NOT absorbed by chlorophyll a
  • This energy is then passed onto chlorophyll a pigments
  • widens absorbable light spectrum
  • increase overall energy capture capability
  • Essentially, chlorophyll a cannot absorb ALL light , only light that is bright green, so this is a helper.
• Accessory pigment to chlorophyll a

  Chlorophyll b
• Chlorophyll b

  • has carbonyl group C=0
  • absorbs yellow, green light
• What does absorbing bright green light mean?


  chlorophyll a accepts everything except bright green. (Example: if something is red it will absorb everything except red, thats why it looks red)
• Carotenoids

  • accessory pigments
  • part of spectrum that allows yellow, orange light to be accessed (use this def instead of absorb)
• Measuring absorption

  • each pigment absorbs light energy @ some wavelengths better than others (eg: carotenoids have yellow-orange capabilities better/more than everyone else, everyone has job/ability they're good at in terms of accessory pigments)
  • Isolate and study specific abilities each is good at
  • use spectrophotometer (measures light intensity)
  • this means if it measures light intensity most at yellow/orange scale, you're looking at a carotenoid
• Plot absorption

  • after measuring absorption...
  • create an action spectrum (lab technique)
  • this determines which wavelengths are best for photosynthesis