Light-harvesting complexes of green plants - Wikipedia

This sketch shows some of the context of Photosystem II in the in the thylakoid membrane. It is part of the process of and providing the electrons to for further transport to the and then to .

Light-harvesting complexes of green plants ..

The light-harvesting complex (or antenna ..

Antenna Complexes for Photosynthesis - HyperPhysics …

A model photosynthetic antenna consisting of four covalently linked zinc tetraarylporphyrins, (P(ZP))3-P(ZC), has been joined to a free base porphyrin-fullerene artificial photosynthetic reaction center, P-C60, to form a (P(ZP))3-P(ZC)-PC60 hexad. As revealed by time-resolved absorption and emission studies, excitation of any peripheral zinc porphyrin moiety (P(ZP)) in 2-methyltetrahydrofuran solution is followed by singlet-singlet energy transfer to the central zinc porphyrin to give (P(ZP))3-1P(ZC)-P- C60 with a time constant of ~50 ps. The excitation is passed on to the free base porphyrin in 240 ps to produce (P(ZP))3-P(ZC)-1P-C60, which decays by electron transfer to the fullerene with a time constant of 3 ps. The (P(ZP))3-P(ZC)-P(·)+-C60(·)- charge-separated state thus formed has a lifetime of 1330 ps, and is generated with a quantum yield of 0.70 based on light absorbed by the zinc porphyrin antenna. The complex thus mimics the basic functions of natural photosynthetic antenna systems and reaction center complexes.

31/12/2017 · Antenna Complexes for Photosynthesis ..

Rienk van Grondelle studied physics at VU University Amsterdam. He obtained his Ph.D. under the supervision of Prof. Dr. Lou Duysens. In 1982, he returned to VU University, and in 1987, he was appointed full professor. At VU University, he has built a large research group studying the early events in photosynthesis. R.v.G. has made major contributions to elucidating the fundamental physical mechanisms that underlie light harvesting and charge separation. He has developed theoretical tools for understanding complex spectroscopic data. Using multidimensional electronic spectroscopy, he recently showed that ultrafast charge separation is driven by specific molecular vibrations that allow electronic coherences to stay alive. He proposed a molecular model for photoprotection and demonstrated that the major plant light-harvesting complex operates as a nanoswitch, controlled by its biological environment. These results, of utmost importance for understanding photosynthesis, have inspired technological solutions for artificial and/or redesigned photosynthesis, as a route toward sustainable energy production.

The process of photosynthesis is initiated by the capture ..

N2 - A model photosynthetic antenna consisting of four covalently linked zinc tetraarylporphyrins, (P(ZP))3-P(ZC), has been joined to a free base porphyrin-fullerene artificial photosynthetic reaction center, P-C60, to form a (P(ZP))3-P(ZC)-PC60 hexad. As revealed by time-resolved absorption and emission studies, excitation of any peripheral zinc porphyrin moiety (P(ZP)) in 2-methyltetrahydrofuran solution is followed by singlet-singlet energy transfer to the central zinc porphyrin to give (P(ZP))3-1P(ZC)-P- C60 with a time constant of ~50 ps. The excitation is passed on to the free base porphyrin in 240 ps to produce (P(ZP))3-P(ZC)-1P-C60, which decays by electron transfer to the fullerene with a time constant of 3 ps. The (P(ZP))3-P(ZC)-P(·)+-C60(·)- charge-separated state thus formed has a lifetime of 1330 ps, and is generated with a quantum yield of 0.70 based on light absorbed by the zinc porphyrin antenna. The complex thus mimics the basic functions of natural photosynthetic antenna systems and reaction center complexes.

Light-Harvesting Antenna Complex.

Yes, it's not an easy topic.
Visible light has wavelengths from 400nm (violet-blue) to 700nm (red), and chlorophyll can absorb at all these wavelengths (just not so efficiently at green wavelengths, which is why plants appear green). Other pigments used by photosynthetic organisms often absorb optimally at the wavelengths that chlorophyll is not so efficient at using, but they will also tend to have a broad spectrum.
Energy transfer through the antenna complex is not as simple as the transfer of photons, as you rightly suggest. Unfortunately, it is also not as simple as the transfer of electrons. It happens by a process called radiationless energy transfer, whereby an excited electron drops back to its ground state and the released energy is immediately absorbed by an electron in the next molecule, without any photon being emitted. Transfers are very fast (picoseconds) and the molecules have to be within a certain distance of each other (Wikipedia suggests less than 10nm).
I've only given a very brief overview so please re-post if you have more questions, and maybe some other people on this site will have more to add. However, this whole area is at the very borderline of biology and physics, so if you can find a site called 'askaphysicist', you might get a more thorough answer!

Photosynthesis: The Role of Light - Biology Pages

The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment−pigment and pigment−protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.