生理名词解释（Physiological noun interpretation）.doc

生理名词解释（Physiological noun interpretation） The different periods of cell cycle and their main events are briefly described Answer: cell cycle is divided into interphase (phase G1, phase S, G2 phase) and division phase (phase M) The main events during each period: (1) G1: correlation with DNA promoter, for cell growth, the decision to split and copy preparation; (2) S: DNA synthesis, chromatin assembly and centriole duplication; (3) G2: copy check and split preparation; (4): M chromosome separation and cytokinesis. The proliferation status of G1 phase cells is briefly described Answer: just split into sub cells only half of the mother cell in the volume, so the cells usually grow to doubling before they split again, the main phase of cell growth is early G1 period, then a large number of cell nutrition, encoding mRNA, tRNA, rRNA gene and ribosomal protein are active therefore, transcription, protein synthesis and metabolism activity is very strong, the cell volume increased rapidly in the early G1 period, there is a decision whether the key period of future cell division, called the restriction point, over the limit point cells after entering the late G1 phase, S phase to start filtering, some of the key ingredients in late G1 phase cells initiate replication the starting point in DNA replication before assembling the replication complexes, attract DNA polymerase comes when DNA synthesis begins when cells enter the S phase. The different stages and stages of the first prophase of meiosis Answer: the meiosis prophase is complex, can be divided into 5 stages: (1): leptotene interphase chromatin in the unwinding state began to agglutinate, become slender spiral linear chromosomes, in fine local, visible small beads round, called karyotin, leptotene chromosome has copy, but still a single chromosome string, not recognize two chromatids; (2): also known as zygotene zygotene, in this period, a form from the maternal side of the same size to 22 pairs of homologous chromosome