Antenna Complexes for Photosynthesis - HyperPhysics …
The light absorption processes associated with take place in large protein complexes known as photosystems. The one known as Photosystem II contains the same kind of as but in a different protein environment with an absorption peak at 680 nm. (It is designated P680). The binding protein for PSII is much smaller than that for PSI, about 47,000 compared to 110,000. It resonates from energy transmitted by about 250 chlorophyll a and b in equal numbers. Its core contains xanthophylls but no beta carotene (Moore).
31/12/2017 · Antenna Complexes for Photosynthesis ..
Algae are a very diverse group of predominantly aquatic photosynthetic organisms that account for almost 50% of the photosynthesis that takes place on Earth. Algae have a wide range of antenna pigments to harvest light energy for photosynthesis giving different types of algae their characteristic colour. Early work done with algae contributed much to what is presently known about the carbon dioxide fixation pathway and the light harvesting reactions. The processes of photosynthesis in algae and higher plants are very similar. From among the three types of carbon dioxide‐concentrating mechanisms known in photosynthetic organisms, two types are found in different types of algae. Algae are proposed to play a role in the global carbon cycle by helping remove excess carbon dioxide from the environment. Recently, algae are recognized as a promising biodiesel source due to its efficient absorption and conversion of solar energy into chemical energy.
The major antenna pigments in algae include chlorophylls, phycobiliproteins and carotenoids and the variation in the composition and relative abundance of these pigments give algae their distinctive colour.
Photosynthesis: Reaction and Antenna Complexes - …
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!
in the Antenna Complexes of Photosynthetic Organisms
The capture of light energy for is enhanced by networks of in the arranged in aggregates on the thylakoids. These aggregates are called antennae complexes. Evidence for this kind of picture came from research by Robert Emerson and William Arnold in 1932 when they measured the oxygen released in response to extremely bright flashes of light. They found that some 2500 molecules of was required to produce one molecule of oxygen, and that a minimum of eight photons of light must be absorbed in the process.
Light-Harvesting Antenna Complex.
Moroney JV and Somanchi A (1999) How do algae concentrate CO2 to increase the efficiency of photosynthetic carbon fixation? Plant Physiology 119: 9–16.
as excitation energy via light-harvesting antenna ..
Higher temperatures reduce the efficiency of photosynthesis resulting in a loss of agricultural productivity (biologists estimate a 10% drop for every degree increase).