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Interphase is the phase of the cell cycle in which a typical cell spends most of its life. Interphase is the 'daily living' or metabolic phase of the cell, in which the cell obtains nutrients and metabolizes them, grows, reads its DNA, and conducts other "normal" cell functions.〔 The majority of eukaryotic cells spend most of their time in interphase. This phase was formerly called the resting phase. However, interphase does not describe a cell that is merely resting; rather, the cell is actively living, and preparing for later cell division, so the name was changed. A common misconception is that interphase is the first stage of mitosis. However, since mitosis is the division of the nucleus, prophase is actually the first stage.〔(The Cell Cycle & Mitosis Tutorial ) The Biology Project – Cell Biology. University of Arizona.〕 In interphase, the cell gets itself ready for mitosis or meiosis. Somatic cells, or normal diploid cells of the body, go through mitosis in order to reproduce themselves through cell division, whereas diploid germ cells (i.e., primary spermatocytes and primary oocytes) go through meiosis in order to create haploid gametes (i.e., sperm and ova) for the purpose of sexual reproduction. Chromosomes are copied. ==Stages of interphase== There are three stages of interphase, with each phase ending when a cellular checkpoint checks the accuracy of the stage's completion before proceeding to the next. The stages of interphase are: * G1 (Gap 1), in which the cell grows and functions normally. During this time, a high amount of protein synthesis occurs and the cell grows (to about double its original size) - more organelles are produced, the volume of cytoplasm increases and mitochondria and chloroplasts divide. If the cell is not to divide again, it will enter G0.〔Cummings, M. R. (2014). Human Heredity: Principles and Issues (10th ed., pp. 28-29). Belmont, CA: Brooks/Cole.〕 * Synthesis (S), in which the cell duplicates its DNA (via semiconservative replication). * G2 (Gap 2), in which the cell resumes its growth in preparation for division. * In addition, some cells that do not divide often or ever, enter a stage called G0 (Gap zero), which is either a stage separate from interphase or an extended G1. The duration of time spent in interphase and in each stage of interphase is variable and depends on both the type of cell and the species of organism it belongs to. Most cells of adult mammals spend about 20 hours in interphase; this accounts for about 90% of the total time involved in cell division.〔Mader, S. S. 2007. Biology 9th Ed. McGraw Hill Higher Education, Boston, MA, USA. ISBN 978-0-07-325839-3〕 Interphase includes G1, S, and G2 phases. Mitosis and cytokinesis, however, are separate from interphase. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「interphase」の詳細全文を読む スポンサード リンク
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