Monday, September 8, 2014

Chloroplasts

Image taken from: https://benchprep.com/blog/wp-content/uploads/2012/08/chloroplast2.jpg

Image taken from: http://blog.canacad.ac.jp/bio/BiologyIBHL1/files/1477622.jpg


Chloroplasts
  • found in mesophyll cells
  • site for photosynthesis
  • surrounded by double membrane called chloroplast envelope
  • thylakoids are fluid-filled sacs
  • a stack of thylakoids is called a granum
  • stroma is a gel-like fluid that surrounds the grana
  • stroma contains soluble enzymes of the Calvin cycle, sugars, organic acids, etc.
  • excess carbohydrates from photosynthesis is stored as starch grains in the chloroplast
  • the two main photosynthetic pigments, chlorophyll and carotenoids, are embedded at the surface of thylakoid membranes
Chlorophyll
  • converts light energy to chemical energy
  • absorb mainly red and blue-violet light 
  • reflects green light which gives leaves their green colour
Carotenoids
  • yellow, orange, red or brown pigments
  • absorb strongly in blue-violet light

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