An extract on #taekookfanart
In mammals, light controls the sense of sight and the circadian clock by activating light-sensitive proteins in photoreceptor cells in the eye's retina. In the case of vision, light is detected by rhodopsin in rod and cone cells. In the case of the circadian clock, a different photopigment, melanopsin, is responsible for detecting light in intrinsically photosensitive retinal ganglion cells.
The release of calcium ions from the endoplasmic reticulum into the cytosol results in its binding to signaling proteins that are then activated; it is then sequestered in the smooth endoplasmic reticulum and the mitochondria. Two combined receptor/ion channel proteins control the transport of calcium: the InsP3-receptor that transports calcium upon interaction with inositol triphosphate on its cytosolic side; and the ryanodine receptor named after the alkaloid ryanodine, similar to the InsP3 receptor but having a feedback mechanism that releases more calcium upon binding with it. The nature of calcium in the cytosol means that it is active for only a very short time, meaning its free state concentration is very low and is mostly bound to organelle molecules like calreticulin when inactive.
Calcium is used in many processes including muscle contraction, neurotransmitter release from nerve endings, and cell migration. The three main pathways that lead to its activation are GPCR pathways, RTK pathways, and gated ion channels; it regulates proteins either directly or by binding to an enzyme.
The sea takes its name from the island of Marmara, which is rich in sources of marble, from the Greek (marmaron), "marble".
The sea's ancient Greek name Propontis derives from pro- (before) and pontos (sea), deriving from the fact that the Greeks sailed through it to reach the Black Sea, Pontos. In Greek mythology, a storm on Propontis brought the Argonauts back to an island they had left, precipitating a battle where either Jason or Heracles killed King Cyzicus, who mistook them for his Pelasgian enemies.
The central peninsula on the east side of the harbour and the area immediately opposite on the west side are the sites of the original city, which resulted from the merger of Parrtown and Carleton. The western side of the central peninsula subsequently saw increased development and currently includes the central business district (CBD) and the Trinity Royal Heritage Conservation Area, which together are referred to as "Uptown" by residents throughout the city. The term "Uptown" comes from the time when the city was an active port and people at the slips would go up the hill to the city. In addition, most of the central peninsula is situated on a hill. This central area of Saint John is only rarely called "Downtown." The south end of the central peninsula, south of Duke Street, is appropriately called the South End.