Plant cell internal structure can be divided into: cell wall, cell membrane, cytoplasm and nucleus。Compared to animal cells and plant cells, there is no cell wall, structure and function of each part and other similar plant cells。
In all parts of cell structure function is introduced:A, cell wall: fixed on cell morphology, support and protect the internal structure:1, to maintain cell shape, control cell growth cell wall increased mechanical strength, and under internal protoplast because of vacuoles absorb water and produce turgor pressure, so that the cell has a certain shape, it's not only protect the protoplast, and maintain the organs with the inherent form of the plant。
In addition, the wall control the cell growth, because cells to expand and elongation of the premise is to make the cell walls of relaxation and irreversible stretching。
2, the cell walls of material transportation and information transmission allows, polysaccharide and other small molecules and ions by low molecular weight protein, and large molecules or microorganisms such as resistance to the outside。
Therefore, cell wall are involved in the material transportation, reduce transpiration, prevent moisture loss (secondary wax on the surface of the wall, etc。
), plant water potential adjustment and a series of physiological activities。 Pit on the cell wall or plasmodesmata size affected by the intensity of cell physiological age and metabolic activity, so the cell walls of transport has a regulatory role of intercellular substance。
In addition, the cell wall is also a chemical signal (hormone, growth regulator, etc。), physical signals (wave, pressure, etc。
) transmission medium and pathways。3, the cell walls of defense and resistance in some segments of oligosaccharides can induce the formation of plant protection element (phytoalexin), they also have a regulatory role on other physiological processes, with the fragments of regulating the activity of oligosaccharides called oligosaccharides (oligosaccharin)。
Will a heptyl glycosidase applying soy oligosaccharides element cell, can make responsible for synthetic gene activation of antimicrobial inhibited the growth of the mold and produce antibiotics。
The function of a variety of oligosaccharide, complex and diverse, such as some factor known as protease inhibitors, play a role in plant resistance to plant diseases and insect pests; Some oligosaccharides can make plants produce allergic death, which kept the pathogens from further proliferation; And oligosaccharides element involved in the regulation of plant morphogenesis。
Stretch of cell wall proteins except as structural components, and preventing the function of art。 Such as resistance of cucumber varieties infection after a mold, its cell wall of hydroxyproline content in the sensitive varieties increase faster than。
4, other function: in the cell wall enzymes are widely involved in the synthesis of cell wall polymer, transfer, hydrolysis, extracellular material conveying and defensive role within the cell。
Second, the cell membrane, material in and out of the cell channel; Biological information communication, the basis of material exchange; Cell membrane has important physiological functions, it even the stability of the cell metabolism of intracellular environment, can adjust again and select material in and out of the cell。
The cell membrane by pinocytosis (pinocytosis), phagocytosis (phagocytosis) or cell function (exocytosis) vomit, absorption, digestion and discharge of the cell membrane outside material。
In the cell recognition, signal transmission, cellulose synthesis and microfibril assembly, etc。, plasma membrane also play an important role。
Some intercellular communication is not accomplished by receptors on the cell membrane, such as certain cells secrete sterols substances, these substances can be used as a signal, exchange of information with other cells, but the material is not and receptors on the cell membrane, but through the cell membrane, and the nucleus or certain receptors in the cytoplasm, thus mediated exchange of information between two cells。
So the physiological function of cell membrane is not very great。 Is only used to protect the cells。Three, the cytoplasm: provide cells with water, inorganic salt and other nutrients, Cytoplasmic matrix is also called the cytoplasmic sol (cytosol) is homogeneous in the cytoplasm and translucent colloidal part, filling between other physical structure。
Four, the nucleus: control cell growth and reproduction。 The nucleus is the genetic information database, is the control center of the cell metabolism and genetic。
1。 Storage and genetic material is copied。 Can be seen from the structure of the nucleus, the nucleus of chromatin, is the most important structure of the components of chromatin is protein and DNA molecules, and DNA molecules is the main genetic material。
When the genetic material to transfer must be replicated in the nucleus。 So, the nucleus is the genetic material storage and replication。
2。 The cell genetic and metabolic activity of control center。 Through genetic material is copied onto their offspring after, at the same time, the genetic material must also will show the biological traits of its control, the vast majority of these genetic material exists in the nucleus。
So, the nucleus and cells, genetic and cellular metabolic activity control center。
