| Abstract from DBPedia | The cell is the basic structural and functional unit of life forms. Every cell consists of a cytoplasm enclosed within a membrane, and contains many biomolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites. The term comes from the Latin word cellula meaning 'small room'. Cells can acquire specified function and carry out various tasks within the cell such as replication, DNA repair, protein synthesis, and motility. Cells are capable of specialization and mobility within the cell. Most cells are measured in micrometers due to their small size. Most plant and animal cells are only visible under a light microscope, with dimensions between 1 and 100 micrometres. Electron microscopy gives a much higher resolution showing greatly detailed cell structure. Organisms can be classified as unicellular (consisting of a single cell such as bacteria) or multicellular (including plants and animals). Most unicellular organisms are classed as microorganisms. The number of cells in plants and animals varies from species to species; it has been approximated that the human body contains an estimated 37 trillion (3.72×1013) cells. The brain accounts for around 80 billion of these cells. The study of cells and how they work has led to many other studies in related areas of biology, including: discovery of DNA, cancer systems biology, aging and developmental biology. Cell biology is the study of cells, which were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells. Cells emerged on Earth about 4 billion years ago.細胞（さいぼう、英: cell）とは、全ての生物が持つ、微小な部屋状の下部構造のこと。生物体の構造上・機能上の基本単位。そして同時にそれ自体を生命体と言うこともできる。 細胞を意味する英語の「cell」の語源はギリシャ語で「小さな部屋」を意味する語である。ロバート・フックが1665年に刊行した自著『ミクログラフィア図版集ー微小世界図絵』(仮説社)の中で、「コルクガシの樹皮を観察したら多数の小部屋(cell)が並んでいた」と報告し、これが細胞がcellと呼ばれるようになった起源である。 (Source: http://dbpedia.org/resource/Cell_(biology)) |
