 |
Inhaltsübersicht | Nanomaschinen | Moleküle | Programme | Kurse | Fun | Links |
 |
| > |
Photosystem II
Harvesting Light
Of course, this whole process wouldn't be very efficient if plants had to wait for photons to hit that one special chlorophyll in the reaction center. Fortunately, the energy from a light-excited electron is easily transferred through the process of resonance energy transfer. Thanks to the mysteries of quantum mechanics, the energy can jump from molecule to molecule, as long they are close enough to each other. To take advantage of this property, photosystems have large antennas of light-absorbing molecules that harvest light and transfer their energy inwards to the reaction center. Plants even build special light-harvesting proteins that sit next to the photosystems and assist with light collection. The picture shows a top view of photosystem II (PDB entry 1s5l), showing all of the light-absorbing molecules inside. The central chlorophyll molecule of the reaction center is shown with the arrow (notice the second reaction center in the bottom half--photosystem II is composed of two identical halves). The little triangular molecules at top and bottom, stuffed full of chlorophyll and carotenoids, are light-harvesting proteins (PDB entry 1rwt).Next: Exploring the Structure
Previous: The Reaction Center
Last changed by: A.Honegger,