Wild—type photosynthetic organisms all contain carotenoids. These photosynthetic carotenoids are mainly packaged (together with the chlorophylls or bacteriochlorophylls) into specific pigment-protein complexes. This review lecture summarises the main types of photochemical reactions which carotenoids undergo in vitro and emphasises the organising role of the apoproteins, of these pigment—protei...

Photosynthetic organisms are capable of harvesting solar energy with near unity quantum efficiency. Even more impressively, this efficiency can be regulated in response to the demands of photosynthetic reactions and the fluctuating light-levels of natural environments. We discuss the distinctive design principles through which photosynthetic light-harvesting functions. These emergent properties...

Several groups of chlorophyll-bearing photosynthetic organisms often coexist in anoxic waters. Because of the close similarity between the absorbance spectra of chlorophyll a (in cyanobacteria and algae) and the chlorophylls of green sulfur bacteria (Chl-GSB) it is difficult to distinguish these two groups of organisms where they co-occur. We have developed a simple method to measure both chlor...

The effect of carotenoids on stability of model photosynthetic pigment-protein complexes subjected to chemical oxidation with hydrogen peroxide or potassium ferricyanide was investigated. The oxidation of carotenoid-less and carotenoid-containing complexes was conducted in the presence or absence of ascorbic acid. The progress of the reactions was monitored by use of absorption and fluorescence...

Photosystem II is a specialized protein complex that uses light energy to oxidize water, resulting in the release of molecular oxygen into the atmosphere, and to reduce plastoquinone, which is released into the hydrophobic core of the photosynthetic membrane. All oxygenic photosynthetic organisms, which include plants, algae and some bacteria, depend on photosystem II to extract electrons from ...