Concerced cells
Cytological development
Judging from the research cell biology can be divided into three levels: micro level, micro level and molecular level.
Vertical axis from the time history of cell biology point of view can be roughly divided into four main phases:
Phase I: from the late 16th century to the 1830s, is found in cells and cell stage of the accumulation of knowledge.
Phase II:by observing a large number of plants and animals, people gradually realized that different kinds of biological cells are formed by the different materials.
Phase III: From the 1930s to the 1970s, the emergence of electron microscopy, to bring the third-largest cellular development period, which just 40 years, not only found in cells of various types of ultrastructure, but also understanding the cell membrane, mitochondria, chloroplasts of different structural features that make the development of cell biology cytology.De Robertis et al published in the 1924 general cytology (General Cytology), when the fourth edition in 1965, named Cell Biology (Cell Biology), which is one of the earliest cell biology textbook.
Phase IV: From the 1970s the emergence of recombinant DNA technology to the current, cell biology and molecular biology combined with more and more closely study the molecular structure of cells and their role in life activities as a major task, gene regulation, signal transduction, cancer biology, cell differentiation and apoptosis of contemporary research focus.
Biology understanding
Cell biology is not so much a discipline, rather it is a field. This can be understood in two ways: first, it is the core issue of the nature of the developmental and genetic ─ ─ put together at the cellular level, this is not confined to a range of disciplines. Second, it has cross many disciplines, even hard to limit. For example, the study material, the single-cell protozoan is the simplest animals, the most complex cells, because they set a number of functions in one;
In particular, is one of the ciliates, not only for the study of certain issues, such as cilia and flagella movement, particularly beneficial for developmental and genetic studies have accumulated a wealth of valuable information.
However, such studies can also be included in the scope of Protozoology.
Second, the research question, the immunity is one of the important functions of cells, cell-mediated immunity should be the scope of cell biology, immunology but also the basic problem.
Because a wide range of interdisciplinary, although the broad range of cell biology, but some subjects did not like some of the branches divide ─ ─ such as cytology, as, according to the perspective from which is divided into cells, cell morphology, cell chemistry.
If its content should be properly classified, can first be divided into two aspects: First, the various components of cell structure and function (according to the specific object of study), this should be the basis for further research, to which have set out, for example, genomic and gene expression, chromatin and chromosomes, organelles, cell surface film and the film system, cytoskeleton, extracellular matrix, and so on.
Second, it is based on the life of the cell activity, such as cell division, growth, movement, excitability, differentiation, aging and disease, etc., of cells in the course of these changes, resulting in the mechanism of these processes.
Of course this is only an artificial division, each of these areas are not isolated, but are related.
About the various components from the cells, such as the surface film and the extracellular matrix is closely related to the surface film and not simply covered with a layer of cytoplasm membrane, but by some of the fine structure ─ ─ knew one of which is actin molecules, which in turn linked to the cytoskeleton of the cytoplasm is closely linked with the ─ ─. This surface film is closely related to and within cells. On the other hand, starting from the research problem, research division, differentiation and other biological phenomena, is inseparable from the structure foundation.
For example, research on cell division involves dressing how chromatin into chromosomes, chromosome division and movement, cytoskeletal changes, including tubulin polymerization and depolymerization, and surface film formation on the cleavage furrow, as well as the regulation of cell division and control. Another example is to understand the removal of cells during the differentiation of certain cell organelles in the changes in their characteristic structure of the protein changes, mainly to understand the cause but also the material basis of differentiation and how these substances act on the level of gene regulation, leading to related genes are activated.
Although the focus of the study can be seen artificially divided, but must take a holistic view of cells, must take the life processes and cellular components of the structure and function of link.
Cell differentiation
Since the cell biology of the main task is linked to developmental and genetic, cell differentiation, the importance of this issue is self-evident.
Because the whole organism, the genetic characteristics of not only appear in the grown individuals, but in the whole course of life displayed continuously.
At the cellular level, cell differentiation is shown the process of genetic characteristics, such as birds, reptiles of the lens, which contains crystal protein is α, β, δ three, unlike mammals, which contain α, β , γ three. Crystal differentiation in birds in a large number of the first δ crystal protein, but the crystal differentiation in mammals but can not find this protein.
Visible characteristics of a cell differentiation occurs, is the emergence of their genetic characteristics.
But this is only at the cellular level on a biochemical traits (specific proteins) in a specialized cell in terms of appearance, of course, is still relatively simple, if related to a cell formed by a number of morphological traits, the situation will much more complex, but the process is still occurring traits genetic performance of the process.
As an example of such a crystal cell differentiation, cell biology, termed terminal differentiation, which is the mature differentiation, the differentiation of these cells is the product of end products.
As easily obtained, easy to analyze relatively simple product and other reasons, the study of cell differentiation studies on terminal differentiation accounts for a large proportion of research is more than red blood cells, muscle cells, pancreas cells, crystal cells, melanocytes, cartilage cells.
A frequently cited example is the conversion of hemoglobin in red blood cells.
Red blood cells of human embryos first appeared in the early stage embryo hemoglobin, fetal hemoglobin was gradually replaced by three months after the fetus, which in turn was replaced by hemoglobin into the body. Hemoglobin has a lot of these studies.
For example, they are each composed of those peptides, these peptides interact in the developing individual case, and their respective composition and sequence of amino acids, each peptide chain loci, as well as gene structure have been more clear, the work can be said is very deeply.
However, the trace in the end some issue has not been a clear answer, not even the answer ─ ─ This also applies to the terminal differentiation of other cell research.
For example, why hemoglobin in red blood cell stage embryos but not in other cells appear?
Why does the conversion of hemoglobin?
About the previous question, some people have, respectively, from chicken oviduct cells (no heme) and red blood cells (hemoglobin produced) to extract chromatin, enzymes to cut, observed two sources of chromatin resistance to the different enzyme . Globin gene of red blood cells containing nuclear body paragraphs more relaxed configuration, thus easy to be affected; Configuration is also more relaxed RNA polymerase transcription of messenger RNA in the above provided the conditions.
But if pressed down, why only in red blood cells in the nucleosome configuration is loose?
How RNA polymerase recognizes this paragraph? These issues need further study.
Secondly, with regard to the embryonic stage of fetal hemoglobin heme conversion. Secondly, with regard to the embryonic stage of fetal hemoglobin heme conversion.
Two kinds of two fluorescent dye labeled antibody was observed in the same red blood cells in the presence of two heme, indicating that conversion is not because there are different cells, but because of the same cells have to produce a different hemoglobin.
What makes blood cells to stop producing the original and produce new hemoglobin? May be said to be development of "procedures", but also answer the material growth process to achieve what is the basis.
All of these questions will allow us to understanding the selective expression of the gene have a great forward.
Cell sociology
Cell biology research is often happy to use cultured cells, it has the advantage of providing a sufficient amount of cells for biochemical analysis, and only one cell, relatively simple materials, facilitate the analysis results.
But for some aspects of the studies is inadequate, because the cells in any organism are in a society, and other cells are mixed with varying degrees in their life activities can not be adjacent the impact of other cells, and even adjacent cells of similar, their situation is much more complex than the cultured cells.
Therefore, some problems or difficult to culture cells, or the results only partially reflect the real situation, in order to study a group of cell-cell interaction between cells, cell sociology has been put forward.
Cell sociology quite extensive, including various cells or cells of the same mutual recognition, cell aggregation and adhesion, cell-cell communication and information exchange, cells and extracellular matrix interactions, and even including cell differentiation group pattern formation.
Some have accumulated some information from a sociological point of the destination cell depth will continue to provide a more systematic and useful information.
As the cell is a cell population as the object of sociology, and some problems also need to understand the developmental biology, it is likely to develop cell biology and developmental biology to become a bridge between.
Looking cell biology, to remove the above work on the cellular components ─ ─ structure and function, as well as a variety of biological phenomena will continue in-depth understanding ─ ─ outside, is what led to orderly selective gene expressed, may be focused on issues of the future; In addition, cell sociology will more and more attention.
Looking to the future
1950 people are still not clear how much of their chromosomes, but by 2000, "Human Genome Project," working draft completed, marking to study gene function-based post-genome era.
Subsequently proteomics (proteomics), RNA genomics (RNomics), glycomics (glycomics), metabolomics (metabolomics) and other "omics" research have been on stage as well as computational biology, nano-biology, into a period of rapid development of systems biology can be expected in the near future, biological science of human society will bring a new stage of development.
Human experience of the hunter-gatherer civilization long after, about 10,000 years ago to enter the agricultural economy, the 1760s, the British took the lead into the industrial economy, the 20th century, 50 the United States completed the first course of the industrial economy into the information age.
Experts estimate the economic form of "life" of 75 to 80 years to 20 years of this century, will gradually lose its vitality, when the world welcomed the next economic era, the bio-economy era, the economic resources for the biological gene, its core technology for the establishment of the cell and molecular biology based on the types of bio-technology.
