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Atrazine is a chlorinated herbicide of the triazine class. [2] It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), [3] soybean [3] and sugarcane and on turf, such as golf courses and residential lawns.
Tyrone B. Hayes (born July 29, 1967) is an American biologist and professor of integrative biology at the University of California, Berkeley. He is known for his research in frogs, concluding that the herbicide atrazine is an endocrine disruptor that demasculinizes male frogs, causing them to display female characteristics. Hayes is an advocate ...
Photobiology is the scientific study of the beneficial and harmful interactions of light (technically, non-ionizing radiation) in living organisms. [1] The field includes the study of photophysics, photochemistry, photosynthesis, photomorphogenesis, visual processing, circadian rhythms, photomovement, bioluminescence, and ultraviolet radiation effects.
Cyanobacteria photosystem II, dimer, PDB 2AXT. Photoinhibition occurs in all organisms capable of oxygenic photosynthesis, from vascular plants to cyanobacteria. [14] [15] In both plants and cyanobacteria, blue light causes photoinhibition more efficiently than other wavelengths of visible light, and all wavelengths of ultraviolet light are more efficient than wavelengths of visible light. [14]
Photosynthesis usually refers to oxygenic photosynthesis, a process that produces oxygen. Photosynthetic organisms store the chemical energy so produced within intracellular organic compounds (compounds containing carbon) like sugars, glycogen , cellulose and starches .
Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
In oxygenic photosynthesis, water (H 2 O) serves as a substrate for photolysis resulting in the generation of diatomic oxygen (O 2). This is the process which returns oxygen to Earth's atmosphere. Photolysis of water occurs in the thylakoids of cyanobacteria and the chloroplasts of green algae and plants. [3]
The phytochrome chromophore is usually phytochromobilin, and is closely related to phycocyanobilin (the chromophore of the phycobiliproteins used by cyanobacteria and red algae to capture light for photosynthesis) and to the bile pigment bilirubin (whose structure is also affected by light exposure, a fact exploited in the phototherapy of ...