Synthesis
Hemoglobin (Hb) is synthesized in a complex series of steps. The heme part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow. At this point, the nucleus is lost in mammalian red blood cells, but not in birds and many other species. Even after the loss of the nucleus in mammals, residual ribosomal RNA allows further synthesis of Hb until the reticulocyte loses its RNA soon after entering the vasculature (this hemoglobin-synthetic RNA in fact gives the reticulocyte its reticulated appearance and name).
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Famous quotes containing the word synthesis:
“The invention of photography provided a radically new picture-making process—a process based not on synthesis but on selection. The difference was a basic one. Paintings were made—constructed from a storehouse of traditional schemes and skills and attitudes—but photographs, as the man on the street put, were taken.”
—Jean Szarkowski (b. 1925)
“The spider-mind acquires a faculty of memory, and, with it, a singular skill of analysis and synthesis, taking apart and putting together in different relations the meshes of its trap. Man had in the beginning no power of analysis or synthesis approaching that of the spider, or even of the honey-bee; but he had acute sensibility to the higher forces.”
—Henry Brooks Adams (1838–1918)
“If in the opinion of the Tsars authors were to be the servants of the state, in the opinion of the radical critics writers were to be the servants of the masses. The two lines of thought were bound to meet and join forces when at last, in our times, a new kind of regime the synthesis of a Hegelian triad, combined the idea of the masses with the idea of the state.”
—Vladimir Nabokov (1899–1977)