Engelmann, Theodore Wilhelm

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Prof. Th. W. Engelmann (This image is in the public domain because its copyright has expired, via Wikimedia Commons)


Theodore Wilhelm Engelmann (1843 - 1909), a German physiologist, showed that the light reactions of photosynthesis, which capture solar energy and convert it into chemical energy, occur within the chloroplasts and respond only to the red and blue hues of natural light. His experiments involved a modified microscope condenser that allowed him to expose parts of photosynthetically active cells of the green alga Spirogyra to a thin ray of light. His aim was to discover which components of the cell functioned as light receptors.

Further Reading
Energy Luminaries: Theodore Engelmann (National Science Teachers Association)
Photosynthesis: The Light Reactions (Massachusetts Institute of Technology)
Photosynthesis: The Dark Reactions (Massachusetts Institute of Technology)



Cleveland, C. (2014). Engelmann, Theodore Wilhelm. Retrieved from


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