Metabolism is the set of chemical reactions that happen in living organisms to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy and will not occur by themselves, by coupling them to spontaneous reactions that release energy. As enzymes act as catalysts they allow these reactions to proceed quickly and efficiently. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells. The metabolism of an organism determines which substances it will find nutritious and which it will find poisonous. The speed of metabolism, the metabolic rate, also influences how much food an organism will require. (more...)
... that in 1854, Charles S. Drew(pictured) was appointed quartermaster general of the Oregon territorial militia by Democratic governor John W. Davis, but was removed from office when he joined the Know-Nothing Party?
... that the Indonesian literary group Lekra was accused of having foreknowledge of the attempted coup d'état in 1965?
"Ancient documents" is a category of Japanese National Treasures that comprises documents from the Asuka period to the Meiji period, selected for especially high historical or artistic value. The documents consist of letters, diaries, records or catalogues, certificates, imperial decrees, testaments, and maps, housed in temples, museums, libraries, shrines, and private collections. They record early Japanese governance and Buddhism, including contact with China, the organization of the state, and life at the Japanese imperial court. The documents are significant examples of calligraphy. Lettering, in the form of inscribed artefacts, was brought to Japan from China c. 2000 years ago. From 5th-century Korea came classical Chinese books, probably written on paper. Soon after, scribes were appointed to the provinces to record events and report conditions. By the end of the 7th century, reading and writing became part of Japanese life, mostly because of the need for literate officials and the rise of Buddhism, which required the study of written sūtras. (more...)
This natural-colour image shows winter sea ice melting off the eastern coastline of Canada's Baffin Island in summer (the only clouds visible here are along the right edge). Eddies along the coast have fashioned the ice into interlocking swirls, especially near Cumberland Sound (centre). Farther north, the ice is not melting as much. The sea ice retreat captured in this image appears typical of seasonal melt. Since the turn of the 21st century, however, Arctic sea ice extent has declined sharply, experiencing a series of low summertime extents and poor wintertime recoveries.
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