Chlorophyll, chloroplasts, and leaves
How is chlorophyll released from the chloroplasts? Why is chlorophyll
green? Why do leaves on trees change color?
I'm not sure that I understand your first question. Chlorophyll is produced within
the chloroplast and stays in the chloroplasts to function in collecting light energy
for the plant to use for growth. Chlorophyll is a pigment, which means it absorbs
visible light. Because of its particular molecular structure, it absorbs mostly red
and blue light. Therefore, if you shine white light (which contains all of the colors),
red and blue light will be absorbed and the other colors will be transmitted or
reflected. The colors that are left over are perceived by the human eye as green.
Leaves on trees change colors as pigments (including chlorophyll) begin to break down.
Leaves typically contain chlorophyll, anthocyanins (red and blue), and carotenoid
pigments (yellow and orange). As chlorophyll breaks down, the leaf color will reflect
the pigments that are still present in the leaf.
Click here to return to the Biology Archives
Update: June 2012