在学习细胞分裂的有丝分裂和减数分裂的知识内容时,对先后出现的染色体、染色单体(姐妹染色单体)、同源染色体、四分体这四个名词,不少学生由于没有真正弄清它们的来龙去脉,因此,它们之间的关系如何即无法明确,显得莫名奇妙.要解决与此有关的问题无所适从,乱答一通.我以为,要切实解决好这些问题,首先必须理解这四个概念——染色体:在细胞核中分布的容易被碱性染料染成深色的物质称为染色质,主要是由DNA和蛋白质组成.这些物质呈细长的丝状,交织成网状,出现在细胞分裂间期.随后,在细胞分裂期,这些长丝状的染色质高度螺旋化、缩短变粗,就形成了在光学显微镜下可以看见的染色体.由此可知,染色体和染色质是同一 When learning the knowledge of mitosis and meiosis in cell division, many students have not really grasped the four nouns: chromosomes, chromatids (sister chromatids), homologous chromosomes, and tetrads. To understand their ins and outs, therefore, the relationship between them is unclear, and it seems strange. To solve the problems related to this, there is nothing for them to answer. I believe that to effectively solve these problems, we must first understand these four issues. Concept - Chromosome: Chromosome that is distributed in the nucleus and easily stained with basic dyes is called chromatin. It is mainly composed of DNA and protein. These materials are filamentous, intertwined and appear in The interphase of cell division. Subsequently, during the cell division period, these filamentous chromatin are highly spiralized, shortened and thickened to form a chromosome that can be seen under the light microscope. Therefore, it is known that chromosome and chromatin are the same.