Light-harvesting complexA light-harvesting complex consists of a number of chromophores which are complex subunit proteins that may be part of a larger super complex of a photosystem, the functional unit in photosynthesis. It is used by plants and photosynthetic bacteria to collect more of the incoming light than would be captured by the photosynthetic reaction center alone. The light which is captured by the chromophores is capable of exciting molecules from their ground state to a higher energy state, known as the excited state.
PheophytinPheophytin or phaeophytin is a chemical compound that serves as the first electron carrier intermediate in the electron transfer pathway of Photosystem II (PS II) in plants, and the type II photosynthetic reaction center (RC P870) found in purple bacteria. In both PS II and RC P870, light drives electrons from the reaction center through pheophytin, which then passes the electrons to a quinone (QA) in RC P870 and RC P680. The overall mechanisms, roles, and purposes of the pheophytin molecules in the two transport chains are analogous to each other.
Green sulfur bacteriaThe green sulfur bacteria, Chlorobiota, are a phylum of obligately anaerobic photoautotrophic bacteria that metabolize sulfur. Green sulfur bacteria are nonmotile (except Chloroherpeton thalassium, which may glide) and capable of anoxygenic photosynthesis. They live in anaerobic aquatic environments. In contrast to plants, green sulfur bacteria mainly use sulfide ions as electron donors. They are autotrophs that utilize the reverse tricarboxylic acid cycle to perform carbon fixation. They are also mixotrophs and reduce nitrogen.
PseudomonadotaPseudomonadota (synonym Proteobacteria) is a major phylum of Gram-negative bacteria. The renaming of several prokaryote phyla in 2021, including Pseudomonadota, remains controversial among microbiologists, many of whom continue to use the earlier name Proteobacteria, of long standing in the literature. The phylum Proteobacteria includes a wide variety of pathogenic genera, such as Escherichia, Salmonella, Vibrio, Yersinia, Legionella, and many others. Others are free-living (non-parasitic) and include many of the bacteria responsible for nitrogen fixation.
ThermophileA thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though some of them are bacteria and fungi. Thermophilic eubacteria are suggested to have been among the earliest bacteria. Thermophiles are found in various geothermally heated regions of the Earth, such as hot springs like those in Yellowstone National Park (see image) and deep sea hydrothermal vents, as well as decaying plant matter, such as peat bogs and compost.
PhotosynthesisPhotosynthesis (ˌfoʊtəˈsɪnθəsɪs ) is a biological process used by many cellular organisms to convert light energy into chemical energy, which is stored in organic compounds that can later be metabolized through cellular respiration to fuel the organism's activities. The term usually refers to oxygenic photosynthesis, where oxygen is produced as a byproduct, and some of the chemical energy produced is stored in carbohydrate molecules such as sugars, starch and cellulose, which are synthesized from endergonic reaction of carbon dioxide with water.