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Anonymous users2024-02-15Categories: Education, Science, >> Science & Technology.
Problem description: I encountered several problems and wanted to get guidance.
Judgment 1, most animal cells can be migrated during ex vivo culture.
Short answer. 1 Some of the organs of some animals can be regenerated after resection, such as the forelimbs of salamanders. What cellular biological events do you think are involved in the regeneration process?
2 Factors secreted by bacteria (e.g., tripeptide f-met-leu-phe) can cause leukocyte chemotaxis. Briefly describe the basic cellular activities involved in this process.
3 Adhesion molecules are responsible for cell-to-cell adhesion to form tissues, but why do cells that perform physiological functions in the body in the form of single cells, such as lymphocytes or blood cells, also express various adhesion molecules? Give examples of the role that adhesion molecules play in these cells.
Analysis: Most cells grow adherently in culture, divided into fibroblasts and epithelioid cells, and only a few can move around.
Receptor recognition, signal transduction, selective expression of nuclear genes, synthesis of specific proteins, contractile movement of the cytoskeleton.
Although white blood cells and red blood cells usually complete their physiological activities in a single-cell state, they are in special states, such as the aggregation and adsorption of red blood cells in coagulation, the adhesion of white blood cells and the movement of white blood cells in tissues are completed by the adhesion and dissolution of adhesion molecules, for example, white blood cells are migrated on the blood vessel wall by continuous adhesion and dissociation with pseudopod-like movements.
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Anonymous users2024-02-14It should be that the cells lose water when the concentration of the reagent is higher than the concentration of the cell fluid, and when the concentration of the reagent is lower than the concentration of the cell fluid, they absorb water.
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Anonymous users2024-02-13**Intramembrane osmotic pressure, which is the intramembrane concentration when it neither loses or absorbs water.
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Anonymous users2024-02-12Cell membranes are selectively semipermeable membranes that allow some substances to pass through and others to not. The osmotic pressure on both sides of the membrane is not the same, so that the transmembrane penetration of some substances will occur. The osmotic pressure in the membrane is greater than that outside the membrane, and the permeable material flows into the membrane.
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Anonymous users2024-02-111。imitation of false roots; Stem; Leaf; Stem; dark and damp; Spore;
2。Climate; Fossil;
3。Absorbs water and inorganic salts for photosynthesis;
4。sporophyte, gametophyte; Seed; in a damp environment;
5。lichens or mosses;
6。roots, stems, leaves;
7。algae plants; Chlamydomonas and no source water are prepared for the gods;
8。baths; From the sea to the land.
First chromatin is compressed sevenfold to become nucleosomes, then sixfold to become solenoids, then fortyfold to become supersolenoids, and five times to become chromatids.
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Motherhood should be the earliest manifestation of emotion, after a long evolution, there are all kinds of complex feelings, especially social animals, generally have feelings, this evolution is conducive to the unity and cooperation of the whole group, better survival and development, and social animals are more intelligent than solitary animals of the same level, and intelligence can be rapid and infinite development, so emotions are also evolved for the sake of survival struggle.