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The process of origin of cytology and cell biology

The origin process of cytology: The word cell (derived from the Latin cella, originally meaning gap, small chamber) was discovered in 1667 by R. Hooke when he observed slices of cork and saw that the cork contained a A small room named after it. It was not until K.M. Bell discovered the mammalian egg in 1827 that serious observation of the cells themselves began. M.J. Schleiden described in 1838 that cells were produced from a mucus-like matrix through a crystal-like process, and that the nucleus was first produced (nucleoli were also discovered). German pathologist R.C. Virchow (1855) put forward the famous saying "all cells come from cells" based on the study of connective tissue, and founded cytopathology. German zoologist M. Schulze defined a cell in 1861: "A cell is a mass of protoplasm with all the characteristics of life, in which the nucleus is located."

German botanist E.A. Straw In 1875, Sburger first described the colored objects in plant cells and concluded that plants of the same species each have a certain number of colored objects; in 1885, the German scholar C. Rabour proposed the law that the number of colored objects is constant. In 1880, Baraniecki described the spiral structure of colored objects. The next year, Pfitzner discovered chromatin. It was not until 1888 that W. Walder officially named the colored objects in the nucleus chromosomes. German scholar H. Henkin observed the X chromosome in insect sperm cells in 1891, and in 1902 W.L. Stevens, E.B. Wilson and others discovered the Y chromosome. The phenomenon of cell division had already been taken seriously at that time and analyzed carefully. The German botanist W. Hofmeister described indirect division in detail in plants in 1867 and A. Schneider in animals in 1873; the German cytologist W. Fleming discovered chromosomes in 1882. After longitudinal division, the name mitosis was proposed to replace indirect division, and E. Heuser described the chromosome distribution during indirect division; after him, E. A. Strassburger divided mitosis into two divisions that are still in common use today. Prophase, metaphase, anaphase, and telophase; he and other scholars also observed meiosis in plants, and after further research, they finally distinguished the haploid and diploid chromosome numbers. German histologist R. Altmann even believed in 1886 that certain small particles are the simplest, living, "basic organisms of cells" and constitute cells due to their special way of aggregation; this may also be due to misunderstanding Mitochondria and secretory and storage granules. The one that is more easily accepted is the honeycomb or foam theory of the German zoologist O. Beachley in 1888: The cytoplasm is composed of a fine honeycomb structure formed by a relatively viscous substance (hyalopla-sm), which is filled with Another substance called enchylema. This structure was also discovered in 1934 by T.S. Painter in Drosophila and by R.L. King and H.W. Beams in Chironomid. Polytene chromosomes are giant chromosomes found in some gland cells of Diptera larvae. In Drosophila, their length is about 100 times longer than normal chromosomes. Each chromosome consists of many (up to 400) chromosomes. It is composed of stained fibers, showing darkly stained band areas and lightly stained interband areas on the entire chromosome.

The origin process of cell biology: The development of cell biology can be divided into three levels, namely: microscopic level, ultramicroscopic level and molecular level. From the vertical axis of time, the history of cell biology can be roughly divided into four main stages: The first stage: from the late 16th century to the 1830s, is the stage of cell discovery and accumulation of cell knowledge. Through the observation of a large number of animals and plants, people gradually realized that different organisms are composed of various cells. The second stage: from the 1830s to the early 20th century, after the formation of the cell theory, a new research field was opened up. Studying the structure and function of cells at the microscopic level was the main feature of this period. The accumulation of knowledge on morphology, embryology and chromosomes has enabled people to understand the important role of cells in life activities. The publication of Hertwig's monograph "Cells and Tissues" (Die Zelle und die Gewebe) in 1893 marked the birth of cytology.

Later, The Cell in Development and Heredity, edited by Wilson of Columbia University in 1896, and Cytology, edited by Agar of Melbourne University in 1920, were the earliest textbooks in this field. The third stage: From the 1930s to the 1970s, the emergence of electron microscopy technology brought cytology into the third period of development. In just 40 years, not only did various ultrastructures of cells be discovered, but also the understanding of The functions of different structures such as cell membranes, mitochondria, and chloroplasts were understood, allowing cytology to develop into cell biology. General Cytology published by De Robertis et al. in 1924 was named Cell Biology in the fourth edition in 1965. This was one of the earliest cell biology textbooks. The fourth stage: From the emergence of gene recombination technology in the 1970s to the present, cell biology and molecular biology have become more and more closely integrated. Studying the molecular structure of cells and their role in life activities has become the main task. Gene regulation , signal transduction, tumor biology, cell differentiation and apoptosis are contemporary research hotspots.