Human or animal female germ cells and male germ cells combined. In addition to aquatic animals in the process of fertilization outside ^, the rest are females in vivo. In vivo fertilization, also known as Conception or fertilization.
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No. 2
Sexual reproduction of plants when the sperm and egg combine.
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No. 3
◎ fertilization shòujīng
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No. 4
Human or animal male germ cells and female reproductive cells combine
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No. 5
Plant sexual reproduction when sperm and egg combine
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No. 6
Fertilization (fertilization) 】 【Animals Fertilization is the fusion of egg and sperm into a zygote of the process. It is the basic characteristics of sexual reproduction is widespread in the animal sector. At the cellular level, the fertilized egg activation process, including adjustment and gender of the original fusion three main stages. Activation can be regarded as a starting point for individual development, mainly for the egg plasma membrane permeability changes in the efflux of cortical granules, fertilization membrane formation; adjustment occurred in the activated, is to ensure the normal fertilized eggs needed to split the first change; gender from the original fusion role to ensure that the genetic parents, and restore the diploid. At the molecular level, fertilization not only start the dna replication, and activated eggs of mrna, rrna and other genetic information to synthesize proteins required for embryonic development. Brief History of Research Since the 20th century, fertilization research to explore the mechanisms of gender gametes. American scholar f. r · Lilly under the Nereis and sea urchins on the research, first pointed out that the eggs secrete sperm-related substances and acceptance, he called fertilin. Before and after the age of 40, another American scholar a. Taylor to fertilin biological, chemical and immunological characteristics of a series of work carried out to further emphasize the process of egg maturation in the effluent of the importance of fertilization. At the same time, German scholars m. Hartmann believe that the sea urchin fertilization process, not only females with eggs can discharge factors, sperm can be discharged with male factor, the degree of match between the two determines the success or failure of fertilization. Soon, amphibians, found in the fertilization of eggs outside the film role. In 1956, China and other experimental cell scientist Zhu washing experiments in accordance gargarizans proposed secretion of eggs outside the film tube, as required for male and female gametes to achieve fertilization. In mammals, the feel and c. 1951, Zhang r. Austin sperm were also raised in the female reproductive tract must stay for some time, get the ability to penetrate eggs - were able to effectively to fertilize an egg. The discovery of sperm capacitation people to find the last egg in vitro fertilization is unsuccessful mammalian reason, so the higher mammals, and fertilization of human eggs to a new stage. Insemination ◆ vivo fertilization and in vitro fertilization Where male and female broodstock mating, sperm transfer from male to female reproductive tract, fertilization gradually arrived at location (such as the uterus or fallopian tubes), where the fusion of sperm-egg encounter, said in vivo fertilization. Where both sperm and eggs excreted, producing holes in the near or female fertilized in the water, said in vitro fertilization. The former occurred in higher animals such as reptiles, birds, mammals, some mollusks, insects and some fish and small amphibians. The latter is a common mode of reproduction of aquatic animals, such as some fish and some amphibians. Selfing and cross-fertilization is the most animals male and female allogeneic, male and female sexes are separate. Some animals are male and female with the body, the same individual produces both eggs and also produce sperm. In hermaphroditic animals, some of selfing, that is the same individual sperm and egg fused, such as tapeworm; there is still cross-fertilization, that is, individuals of two different sperm and egg combine, such as earthworms. ◆ Single-sperm fertilization and polyspermy Fertilization Unlike animal sperm sperm of lower plants such as bryophytes chemotaxis significantly, but by their active movement, or rely on reproductive tract epithelial cells of the ciliary movement arrived in the vicinity of the egg. Sperm capacitation and acrosome reaction After a number of known mammalian sperm through the female reproductive tract or the cumulus, the package of exogenous sperm proteins have been removed, the sperm plasma membrane changes in chemical and biological characteristics, so that sperm can take part in the process of fertilization. Mammalian sperm exposed to egg by the egg membrane week or transparent with time, specifically some sugar with the egg membrane protein binding, stimulate sperm acrosome reaction: the outer part of the acrosome membrane disappears, the top membrane in vitro trap, the vesicle of the top body with objects, including some enzymes to escape. Further contribute to the sperm acrosome reaction through the egg membrane. In sea urchin eggs, the sperm acrosome reaction stirred egg week is a film of polysaccharide. Most eggs are egg membrane of peripheral, a variety of different egg membrane thickness, mainly composed of mucin or glycosaminoglycan; only a few are naked eggs, such as the coelenterate eggs. When the sperm through the egg membrane, appears after the first adhesive bonding process. The former is loose attachment, free from outside interference temperature, non-species specific, adhesion period, the top body of the original membrane protein into the top of the top protein, sperm acrosomal protein through the egg membrane to accelerate the role; the latter is a strong combination of low temperature can be interference with the species specificity. In the sea urchin sperm plasma membrane has been isolated from an egg membrane glycoprotein with specific binding proteins, known as binding proteins, the molecular weight of about 30000. Egg activation Once contact with the sperm and egg, the egg itself is a series of activation change. In mammals, the eggs, then the performance of cortical reaction, zona pellucida egg membrane reaction and response, which play a blocking polyspermy and stimulate further development of the role of eggs. Cortical reaction in sperm egg fusion of the occasion, starting from the fusion point, breakdown of cortical granules, their contents outside the row, which affected the entire egg cortex. Egg quality and egg membrane response was the restructuring process of cortical granule envelope. Zona reaction of cortical granules with the efflux properties together with the transparent process of the formation of fertilization membrane, egg membrane and membrane separation, the sperm receptor in the disappearance of the zona pellucida, zona pellucida hardening. Sperm-egg fusion Biochemical changes Fertilized eggs before the metabolism of the low level of activity without the synthesis of dna, rna and protein synthesis were minimal. Therefore, the egg discharge, if not fertilized, and soon died. When the surface of sperm and egg combine, the rapid increase in metabolic rate of eggs and begin synthesis of dna. For a detailed mechanism of egg activation is unclear, only knew the sperm only open the program switches to play the role. In addition to sperm, a number of other non-specific chemical or physical treatment, but also make the egg activation, such as acupuncture frog eggs, but also make the excitement. The initial excitement without any new protein synthesis. In the early stages of sea urchin egg activation, membrane permeability to sodium ions, a large number of sodium ions flow, leading to membrane depolarization in seconds; calcium ions released from the cells in stock, so that 20 to 30 seconds Within minutes of free calcium in eggs increased rapidly up to 100 times; with Na + influx, outflow of hydrogen ions, resulting in a minute eggs ph value increased significantly. Changes in these ions, induced cortical reaction, leading to block unwanted sperm into the egg, and stirred a further development of the egg. Eggs increase in intracellular calcium, activation of the eggs arrived the role of calmodulin, which further activate other proteins within the egg. Appears to increase the amount of protein synthesis, dna replication began. In sea urchin eggs, calcium may be through calmodulin, activated eggs of some specific plasma membrane transport proteins, so that the output of hydrogen ions outside the cell. Ph value of the increase in egg, may cause increased rates of protein synthesis and dna replication. The outflow of hydrogen ions depends on the flow of sodium ions. The synthesis of these proteins is not dependent on new synthesis of rna, but stored the eggs in the mrna and ribosomes to cover up the results of activation. Fertilization mechanism is effective to grasp and control of human sexual reproduction and breeding animals, one of the basic guarantee. Human "test-tube baby" was born only a few success stories. Because the normal fertilization and further development of mechanisms there are still many outstanding issues, many animals in vitro fertilization attempts ended in failure. These failures indicate that the importance of basic research. Posts】 【Plants Fertilization is the fusion of two gametes into zygotes process. With the zygote develops into a new individual genetic parents. Fertilization is the central link of sexual reproduction. Higher plants and animals of the male and female parent (ie, male and female) of the genetic characteristics of chromosomes from a haploid sperm and egg fertilization and spread through the offspring. By the sperm and egg fusion produces a new individual, restoring as parent the same as twice the number of chromosomes, inherited the parent of both inherited the same time, the parents both the genetic material of the reorganization, there are likely to exhibit new traits. Therefore, the offspring produced by fertilization, the genetic characteristics of both the parental generation, but also the performance of a specific individual. Thus, fertilization is not only a continuation of the species in the maintenance of great significance, but also the biological evolution of an important factor. Basic ways There are three: ① the same with reproduction (gametes with the same type); ② vary with reproductive (abnormal gametes with); ③ type of reproductive eggs (sperm-egg tie). Fertilization of the three forms reflect the fusion of two gametes from a few obvious differentiation to the evolutionary process of differentiation. ◆ the same with the reproductive ◆ vary with reproductive Fusion of two gametes in the difference between a fixed size, which is the further differentiation of cell performance. For example, pine green algae in the genus, in a repeat of individuals to generate two kinds of bifurcation asci with, in an ascus with two flagella arising from the shape of a large gametes, and the other with the former produced in asci morphology similar and much smaller form gametes, female gametes called large and small as male gametes. ◆ egg-type reproductive Multicellular algae in the individual groups can be formed simultaneously both male and female gametes. Primitive cells from a male after numerous slender vertical division creates a lot of sperm with two flagella; eggs is increased by a female from the original cells, mature spherical, non-flagellated, swimming sperm swim to be Sheath coated eggs, sperm and egg fusion by a complete fertilization. Algae and fungi and plants, the way of other sperm-egg fusion. For example, mold is a fungus in the water, the female organ - the end of oocysts in hyphal formation in the development of the oocysts from one or more eggs; sperm sperm-producing devices in the vicinity of oocyst production, sperm quantity, can not swim action. In fertilization, the fertilized by the sperm tube devices grow and sperm penetration of egg sac injection to be achieved next to fertilize eggs. No algae green algae are separated from the water mold sex organs are similar, but the sperm active, mature eggs of only one oocyst. Sperm from the sperm after the device is released through the opening into the oocyst oocysts beak and egg fusion. In the mosses and ferns, the sperm and egg cells are harbored in a multi-organ, the fertilization can not leave the water conditions. To money such as bottles shaped like the female organ, called the archegonium. Archegonia and antheridia were born in the leafy gametophyte of the care. To money is dioecious. In the archegonium produces only one egg, and antheridia produce many of the long-shape with two curly sperm flagella. When the device mature sperm, the sperm is released, if the water plant on the back of the sperm to swim to the archegonium and egg to achieve fertilization. Fern archegonium and antheridium in the same body under the surface of gametes, the sperm can swim through the water surface layer of gametes swim into the archegonium. Seed plant reproductive structures more complicated and in the process of sexual reproduction produced a pollen tube, with the pollen tube, fertilization is no longer dependent on water conditions, which is the seed plant adaptation to terrestrial life, an important factor. Produce female gametes in the female gametophyte is large ovule nucellar sporangia at the development. Most of the gymnosperm archegonium remains the structure of the egg in the archegonium to form. Sporangia in the development of small pollen grains, that is, the male gametophyte early. In the male gametophyte form two sperm. Many non-sperm flagellum, but in the cycads and Ginkgo head remain head swimming sperm. Angiosperm female gametophyte is called the embryo sac, which produce eggs directly; complete loss of sperm flagella. These characteristics determine the fertilization of seed plants are tried pollination. Gymnosperm ovules are exposed, after pollination, pollen was sent at the ovule micropyle, and in angiosperms, the ovule in the pistil of the child is living room, but the pollen can not fall directly to the stigma of the ovule, and then germination and growth of pollen tubes from the sperm to the female gamete transport nearby. In gymnosperms, the enter the archegonium is only one of two sperm and egg fusion. Enter the embryo sac in angiosperms, two sperm and eggs and were very fusion. This is the unique double fertilization of angiosperms. Recognition of the process of fertilization 20th century, 40 years have recognized the Chlamydomonas sexual reproduction is called by a controlled substance with pigment. Later testing of cultured cells to further clarify the status of gametes released into the medium relative to the material can cause agglutination of gametes of mating type; that is, from "+" Department of substances released by cells can "-" Department of Cell agglutination, whereas from the "-" cells release substance can be condensed "+" cells, in the same-sex aggregation after cell fusion does not occur. This substance is called the same lectin, which is a sugar protein substance found in the tiny bubbles on the surface flagella, it is not only sexual specificity, and a kind of specificity, is undoubtedly related to gamete adhesion and recognition reaction of the material. Moss and fern eggs concealed in the archegonium, the swimming sperm reaches the archegonium and egg combine to a certain distance of travel required, sperm can be "found" eggs, there is clearly some interaction of the material. In these two groups of plants, the resistance of sperm has been affirmed. Refers to the resistance of eggs or sperm archegonium tend to produce chemicals. w. f. p. Puffy Fair earliest of European fern (pteridium aquilinum) of the sperm to the resistance of the experiments show, produced by the archegonium l-malic acid is effective to attract agents. It will contain tap water (containing 10% agar) 10% l-malate in the dropper into the sperm suspension, malate ions immediately from the dropper to have differential spread to the surrounding medium, the sperm in a move within a matter of seconds, the mouth dropper, immediately move the source of malate. Malate in the absence of running water, the sperm is arbitrary action; if Apple salts in homogeneous solution, which does not exist in the steps of sperm in the solution also maintained a uniform distribution. Equi_set_um was tested in 12 kinds of organic acids, sperm only l-malic acid and tartaric acid sensitive. In angiosperms, the sperm transferred to the embryo sac by the pollen tube. Directional growth of pollen tubes through the style of the reason, there have been various interpretations. Some speculated that the resistance factor is the control of, that that calcium is to attract the pollen tube growth factor; Some believe that by the early growth of pollen tubes in the vegetative nucleus, the control of dna mrna transcription; there is the assumption that directional growth of pollen tubes determined stigma to the ovary potential difference and so on. This is an un_set_tled issue. Mutual Recognition of pollen and pistil to achieve fertilization of angiosperms play a decisive role. Because the choice is first of all male gamete pistil tissue, rather than eggs. In angiosperms, the stigma and style of "screening" of their own role in the most appropriate pollen. Most plants showed wide differences within the same fertilization, if large genetic differences (in the case from time to time the relationship between species) or genetic differences are too small (like a flower, the same individual from the cross between the different flower ) and between individuals are not compatible, this hybridization incompatibility and self-incompatibility phenomenon is the long-term evolution of angiosperms developed not only help maintain the stability of species while maintaining an adaptation of its life force characteristics. Fall pollen on stigma is "acceptable" or was "rejected" the decision on mutual recognition between them. If the affinity of the plant's pollen grains have germinated in the stigma out of a long tube into the stigma, and along the way by a certain style to the embryo sac, where the release of sperm; If the pollen is incompatible with the stigma of , pistil will inhibit pollen germination or pollen tube growth and hinder fertilization. Incompatibility in plants fertilized by the two parental genotypes of the decision, and showed physiological inhibition. Since the physiological basis of incompatibility in Cruciferae and Asteraceae, based on a number of plant studies, that is to identify the pollen and pistil inter-organizational response to the results. And identification of related substances, the party is present in the pollen wall proteins in pollen; party identified in the pistil is the protein covering the stigma surface film. Pollen wall and the wall. Substance is composed of the outer wall of carotenoids and carotenoid esters of poly oxide formed sporopollenin. Formed in the outer wall of the structure of material from the tapetum between the synthesis and transport into the protein, when the deposition of pectin and cellulose wall development, by the pollen itself into the cytoplasm where protein synthesis. Thus, when pollen is mature, the outer wall of a spore body (tapetum) protein produced by genotype control; the inner walls of the gametophyte (pollen) cells control the production of the protein genotypes, which are identified from the role of the protein. Identification of the pollen on the pistil, the current dry-type stigma (stigma maturity without liquid discharge) was quite clear. For example, in Cruciferae and Compositae plants, stigma surface papillary single cell, which with a layer of pectin and cellulose in the wall of the cuticle is not continuous. Papillary cells in the development process, through the wall and cuticle secretion of some substances also form a thin film covering the surface, this film is the main component of proteins, which not only provides a benefit to "capture" the surface of sticky pollen, and with the recognition "receptors" features. When combined with the pollen wall protein occurred then "accept" or "reject" response. Pollen falls on the stigma, stigma water from the swollen, within minutes after exposure, the protein that is released from the pollen wall and stigma surface membrane protein binding, if it is a combination of affinity, pollen germination, the role of the enzyme, stigma cuticle is dissolved, the pollen tube into the stigma and style in the smooth growth. In the case of incompatible pollen tube growth and stagnation, or can not enter the stigma (sporophyte system control), or stop the growth of pollen tubes in the styles and rupture (gametophyte system control). Radish, cabbage, cosmos and sunflowers and other plants in the self-incompatibility in a few hours after pollination, stigma papilla-like cells that produce callose convex lens-like structure; in the mating pro-and no callose response. This reaction can callose as a test within a certain kinship affinity indicators. Pollen to the stigma of a fall germination, and also lead to stigma cells, papillary callose formation (top of the formation of grass plants in the pollen tube callose) This is the incompatibility response. Intraspecific and interspecific incompatibility incompatibility occur this reaction in sign between the two there are certain parental relationship; If neither of pollen germination, nor cause callose papilla cells showed reaction reflects the two parents is not between unrelated hybrid nature, which is often far different families hybridization between the performance of the situation. Pollination and fertilization in vitro 60 years have been the 20th century with the placenta can ovule of angiosperms, the pistil or ovary placed under conditions in vitro pollination and fertilization to achieve. In vitro pollination and fertilization technology in the breeding process may overcome the sexual reproduction as a self exists or hybrid incompatibility barriers means. And plant self-incompatibility barriers in the fertilization process, usually occurs in the stigma or style, that is the result of pollen and stigma recognition reaction tube growth was inhibited, can not enter the stigma or in the style that fertilization failure in growth arrest. Therefore, the possibility of using in vitro pollination of ovules successfully fertilized. This has been successfully tested in the genus Petunia. For example, self-incompatibility and the axillary flower petunia seat with a full fetal ovary ovules were cultured in vitro and taught to self-pollen. Results normal pollen tube growth, and finally the formation of a normal development of the embryo and endosperm of seeds. Obtained from the seeds of in vitro fertilization, the first generation of plants grown as its parent, is diploid, fertile and self-incompatibility and the. On the other hand, in pink, poppy, Solanaceae, and Gramineae plants try some of pollination and fertilization in vitro techniques to overcome hybrid incompatibility. Although many hybrid combinations can achieve fertilization, but failed to get a life force of seeds. Eggs and sperm are significant differences between what the individual? According to "Encyclopedia of China" medical volume contains the human eggs visible, about 0.2 mm in diameter, is the largest human cells, and sperm count even if the length is only 0.06 mm, terms of volume comparison, only thousandths of eggs one. Since this relationship is far from the chance of their appearance, about one egg a month before discharge, and no time limit discharge of 200 million sperm at one time the public. Egg Also responsible for reproductive mission, why the difference between them is so poor individuals do? We must first understand why the animals were divided into two sexes. Some people may say, is to limit the success rate when the spouse to maintain a stable number. Why let the sperm can be _select_ed at the location? The field of evolutionary biology is a major issue. There are many definitions of sexual way, here talking about the biological sexual reproduction has produced eggs, ovaries and other features of these large individual known as female gametes, and those that produce only sperm, pollen and other small gametes called it for the males. Sperm cruising When egg and sperm meet,
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Animals
Fertilization (fertilization) is the fusion of egg and sperm into a zygote of the process. It is the basic characteristics of sexual reproduction is widespread in the animal sector. At the cellular level, the fertilized egg activation process, including adjustment and gender of the original fusion three main stages. Activation can be regarded as a starting point for individual development, mainly for the egg plasma membrane permeability changes in the efflux of cortical granules, fertilization membrane formation; adjustment occurred in the activated, is to ensure the normal fertilized eggs needed to split the first change; gender from the original fusion role to ensure that the genetic parents, and restore the diploid. At the molecular level, fertilization not only start the DNA replication, and activated eggs of the mRNA, rRNA and other genetic information to synthesize proteins required for embryonic development. Brief History of Research Since the 20th century, fertilization research to explore the mechanisms of gender gametes. American scholar F. R · Lilly under the Nereis and sea urchins on the research, first pointed out that the eggs secrete sperm-related substances and acceptance, he called fertilin. Before and after the age of 40, another American scholar A. Taylor to fertilin biological, chemical and immunological characteristics of a series of work carried out to further emphasize the process of egg maturation in the effluent of the importance of fertilization. At the same time, the German scholar M. Hartmann believe that the sea urchin fertilization process, not only females with eggs can discharge factors, sperm can be discharged with male factor, the degree of match between the two determines the success or failure of fertilization. Soon, amphibians, found in the fertilization of eggs outside the film role. In 1956, China and other experimental cell scientist Zhu washing experiments in accordance gargarizans proposed secretion of eggs outside the film tube, as required for male and female gametes to achieve fertilization. In mammals, the feel and C. Zhang 1951 R. Austin sperm were also raised in the female reproductive tract must stay for some time, get the ability to penetrate eggs - were able to effectively to fertilize an egg. The discovery of sperm capacitation people to find the last egg in vitro fertilization is unsuccessful mammalian reason, so the higher mammals, and fertilization of human eggs to a new stage. Insemination ◆ vivo fertilization and in vitro fertilization Where male and female broodstock mating, sperm transfer from male to female reproductive tract, fertilization gradually arrived at location (such as the uterus or fallopian tubes), where the fusion of sperm-egg encounter, said in vivo fertilization. Where both sperm and eggs excreted, producing holes in the near or female fertilized in the water, said in vitro fertilization. The former occurred in higher animals such as reptiles, birds, mammals, some mollusks, insects and some fish and small amphibians. The latter is a common mode of reproduction of aquatic animals, such as some fish and some amphibians. Selfing and cross-fertilization is the most animals male and female allogeneic, male and female sexes are separate. Some animals are male and female with the body, the same individual produces both eggs and also produce sperm. In hermaphroditic animals, some of selfing, that is the same individual sperm and egg fused, such as tapeworm; there is still cross-fertilization, that is, individuals of two different sperm and egg combine, such as earthworms. ◆ Single-sperm fertilization and polyspermy Fertilization Unlike animal sperm sperm of lower plants such as bryophytes chemotaxis significantly, but by their active movement, or rely on reproductive tract epithelial cells of the ciliary movement arrived in the vicinity of the egg. Sperm capacitation and acrosome reaction After a number of known mammalian sperm through the female reproductive tract or the cumulus, the package of exogenous sperm proteins have been removed, the sperm plasma membrane changes in chemical and biological characteristics, so that sperm can take part in the process of fertilization. Mammalian sperm exposed to egg by the egg membrane week or transparent with time, specifically some sugar with the egg membrane protein binding, stimulate sperm acrosome reaction: the outer part of the acrosome membrane disappears, the top membrane in vitro trap, the vesicle of the top body with objects, including some enzymes to escape. Further contribute to the sperm acrosome reaction through the egg membrane. In sea urchin eggs, the sperm acrosome reaction stirred egg week is a film of polysaccharide. Most eggs are egg membrane of peripheral, a variety of different egg membrane thickness, mainly composed of mucin or glycosaminoglycan; only a few are naked eggs, such as the coelenterate eggs. When the sperm through the egg membrane, appears after the first adhesive bonding process. The former is loose attachment, free from outside interference temperature, non-species specific, adhesion period, the top body of the original membrane protein into the top of the top protein, sperm acrosomal protein through the egg membrane to accelerate the role; the latter is a strong combination of low temperature can be interference with the species specificity. In the sea urchin sperm plasma membrane has been isolated from an egg membrane glycoprotein with specific binding proteins, known as binding proteins, the molecular weight of about 30000. Egg activation Once contact with the sperm and egg, the egg itself is a series of activation change. In mammals, the eggs, then the performance of cortical reaction, zona pellucida egg membrane reaction and response, which play a blocking polyspermy and stimulate further development of the role of eggs. Cortical reaction in sperm egg fusion of the occasion, starting from the fusion point, breakdown of cortical granules, their contents outside the row, which affected the entire egg cortex. Egg quality and egg membrane response was the restructuring process of cortical granule envelope. Zona reaction of cortical granules with the efflux properties together with the transparent process of the formation of fertilization membrane, egg membrane and membrane separation, the sperm receptor in the disappearance of the zona pellucida, zona pellucida hardening. Sperm-egg fusion Biochemical changes Fertilized eggs before the low metabolism, no DNA synthesis activity, RNA and protein synthesis were minimal. Therefore, the egg discharge, if not fertilized, and soon died. When the surface of sperm and egg combine, the rapid increase in metabolic rate of eggs and start synthesis of DNA. For a detailed mechanism of egg activation is unclear, only knew the sperm only open the program switches to play the role. In addition to sperm, a number of other non-specific chemical or physical treatment, but also make the egg activation, such as acupuncture frog eggs, but also make the excitement. The initial excitement without any new protein synthesis. In the early stages of sea urchin egg activation, membrane permeability to sodium ions, a large number of sodium ions flow, leading to membrane depolarization in seconds; calcium ions released from the cells in stock, so that 20 to 30 seconds Within minutes of free calcium in eggs increased rapidly up to 100 times; with Na + influx, outflow of hydrogen ions, resulting in a minute eggs pH value increased significantly. Changes in these ions, induced cortical reaction, leading to block unwanted sperm into the egg, and stirred a further development of the egg. Eggs increase in intracellular calcium, activation of the eggs arrived the role of calmodulin, which further activate other proteins within the egg. Appears to increase the amount of protein synthesis, DNA replication began. In sea urchin eggs, calcium may be through calmodulin, activated eggs of some specific plasma membrane transport proteins, so that the output of hydrogen ions outside the cell. The increase of pH value of the eggs will cause increased rates of protein synthesis and DNA replication. The outflow of hydrogen ions depends on the flow of sodium ions. The synthesis of these proteins is not dependent on new RNA synthesis, but the mRNA stored in the egg to cover up and the result of active ribosomes. Fertilization mechanism is effective to grasp and control of human sexual reproduction and breeding animals, one of the basic guarantee. Human "test-tube baby" was born only a few success stories. Because the normal fertilization and further development of mechanisms there are still many outstanding issues, many animals in vitro fertilization attempts ended in failure. These failures indicate that the importance of basic research.
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The Plant
Fertilization is the fusion of two gametes into zygotes process. With the zygote develops into a new individual genetic parents. Fertilization is the central link of sexual reproduction. Higher plants and animals of the male and female parent (ie, male and female) of the genetic characteristics of chromosomes from a haploid sperm and egg fertilization and spread through the offspring. By the sperm and egg fusion produces a new individual, restoring as parent the same as twice the number of chromosomes, inherited the parent of both inherited the same time, the parents both the genetic material of the reorganization, there are likely to exhibit new traits. Therefore, the offspring produced by fertilization, the genetic characteristics of both the parental generation, but also the performance of a specific individual. Thus, fertilization is not only a continuation of the species in the maintenance of great significance, but also the biological evolution of an important factor. Basic ways There are three: ① the same with reproduction (gametes with the same type); ② vary with reproductive (abnormal gametes with); ③ type of reproductive eggs (sperm-egg tie). Fertilization of the three forms of integration reflects the differentiation of the two gametes from the few to have a clear division of the evolutionary process. ◆ the same with the reproductive ◆ vary with reproductive Fusion of two gametes in the difference between a fixed size, which is the further differentiation of cell performance. For example, pine green algae in the genus, in a repeat of individuals to generate two kinds of bifurcation asci with, in an ascus with two flagella arising from the shape of a large gametes, and the other with the former produced in asci morphology similar and much smaller form gametes, female gametes called large and small as male gametes. ◆ egg-type reproductive Multicellular algae in the individual groups can be formed simultaneously both male and female gametes. Primitive cells from a male after numerous slender vertical division creates a lot of sperm with two flagella; eggs is increased by a female from the original cells, mature spherical, non-flagellated, swimming sperm swim to be Sheath coated eggs, sperm and egg fusion by a complete fertilization. Algae and fungi and plants, the way of other sperm-egg fusion. For example, mold is a fungus in the water, the female organ - the end of oocysts in hyphal formation in the development of the oocysts from one or more eggs; sperm sperm-producing devices in the vicinity of oocyst production, sperm quantity, can not swim action. In fertilization, the sperm penetration device oocysts grow tube fertilization and sperm injection to fertilize eggs achieved next. No algae green algae are separated from the water mold sex organs are similar, but the sperm active, mature eggs of only one oocyst. Sperm from the sperm after the device is released through the opening into the oocyst oocysts beak and egg fusion. In the mosses and ferns, the sperm and egg cells are harbored in a multi-organ, the fertilization can not leave the water conditions. To money such as bottles shaped like the female organ, called the archegonium. Archegonia and antheridia were born in the leafy gametophyte of the care. To money is dioecious. In the archegonium produces only one egg, and antheridia produce many of the long-shape with two curly sperm flagella. When the device mature sperm, the sperm is released, if the water plant on the back of the sperm to swim to the archegonium and egg to achieve fertilization. Fern archegonium and antheridium in the same body under the surface of gametes, the sperm can swim through the water surface layer of gametes swim into the archegonium. Seed plant reproductive structures more complicated and in the process of sexual reproduction produced a pollen tube, with the pollen tube, fertilization is no longer dependent on water conditions, which is the seed plant adaptation to terrestrial life, an important factor. Produce female gametes in the female gametophyte is large ovule nucellar sporangia at the development. Most of the gymnosperm archegonium remains the structure of the egg in the archegonium to form. Sporangia in the development of small pollen grains, that is, the male gametophyte early. In the male gametophyte form two sperm. Many non-sperm flagellum, but in the cycads and Ginkgo head remain head swimming sperm. Angiosperm female gametophyte is called the embryo sac, which produce eggs directly; complete loss of sperm flagella. These characteristics determine the fertilization of seed plants are tried pollination. Gymnosperm ovules are exposed, after pollination, pollen was sent at the ovule micropyle, and in angiosperms, the ovule in the pistil of the child is living room, but the pollen can not fall directly to the stigma of the ovule, and then germination and growth of pollen tubes from the sperm to the female gamete transport nearby. In gymnosperms, the enter the archegonium is only one of two sperm and egg fusion. Enter the embryo sac in angiosperms, two sperm and eggs and were very fusion. This is the unique double fertilization of angiosperms. Recognition of the process of fertilization 20th century, 40 years have recognized the Chlamydomonas sexual reproduction is called by a controlled substance with pigment. Later testing of cultured cells to further clarify the status of gametes released into the medium relative to the material can cause agglutination of gametes of mating type; that is, from "+" Department of substances released by cells can "-" Department of Cell agglutination, whereas from the "-" cells release substance can be condensed "+" cells, in the same-sex aggregation after cell fusion does not occur. This substance is called the same lectin, which is a sugar protein substance found in the tiny bubbles on the surface flagella, it is not only sexual specificity, and a kind of specificity, is undoubtedly related to gamete adhesion and recognition reaction of the material. Moss and fern eggs concealed in the archegonium, the swimming sperm reaches the archegonium and egg combine to a certain distance of travel required, sperm can be "found" eggs, there is clearly some interaction of the material. In these two groups of plants, the resistance of sperm has been affirmed. Refers to the resistance of eggs or sperm archegonium tend to produce chemicals. W. F. P. Puffy Fair earliest of European fern (Pteridium aquilinum) of the sperm to the resistance of experiments show produced by the archegonium L-malic acid is effective to attract agents. It will contain tap water (containing 10% agar) 10% L-malate of the dropper into the sperm suspension, the malate ion has differential immediately from the dropper to spread to the surrounding medium, the sperm in a move within a matter of seconds, the mouth dropper, immediately move the source of malate. Malate in the absence of running water, the sperm is arbitrary action; if Apple salts in homogeneous solution, which does not exist in the steps of sperm in the solution also maintained a uniform distribution. Equi_set_um was tested in 12 kinds of organic acids, sperm only malic acid and tartaric acid L-sensitive. In angiosperms, the sperm transferred to the embryo sac by the pollen tube. Directional growth of pollen tubes through the style of the reason, there have been various interpretations. Some speculated that the resistance factor is the control of, that that calcium is to attract the pollen tube growth factor; Some believe that by the early growth of pollen tubes in the vegetative nucleus, the control of DNA transcription of the mRNA; there is the assumption that directional growth of pollen tubes determined stigma to the ovary potential difference and so on. This is an un_set_tled issue. Mutual Recognition of pollen and pistil to achieve fertilization of angiosperms play a decisive role. Because the choice is first of all male gamete pistil tissue, rather than eggs. In angiosperms, the stigma and style of "screening" of their own role in the most appropriate pollen. Most plants showed wide differences within the same fertilization, if large genetic differences (in the case from time to time the relationship between species) or genetic differences are too small (like a flower, the same individual from the cross between the different flower ) and between individuals are not compatible, this hybridization incompatibility and self-incompatibility phenomenon is the long-term evolution of angiosperms developed not only help maintain the stability of species while maintaining an adaptation of its life force characteristics. Fall pollen on stigma is "acceptable" or was "rejected" the decision on mutual recognition between them. If the affinity of the plant's pollen grains have germinated in the stigma out of a long tube into the stigma, and along the way by a certain style to the embryo sac, where the release of sperm; If the pollen is incompatible with the stigma of , pistil will inhibit pollen germination or pollen tube growth and hinder fertilization. Incompatibility in plants fertilized by the two parental genotypes of the decision, and showed physiological inhibition. Since the physiological basis of incompatibility in Cruciferae and Asteraceae, based on a number of plant studies, that is to identify the pollen and pistil inter-organizational response to the results. And identification of related substances, the party is present in the pollen wall proteins in pollen; party identified in the pistil is the protein covering the stigma surface film. Pollen wall and the wall. Substance is composed of the outer wall of carotenoids and carotenoid esters of poly oxide formed sporopollenin. Formed in the outer wall of the structure of material from the tapetum between the synthesis and transport into the protein, when the deposition of pectin and cellulose wall development, by the pollen itself into the cytoplasm where protein synthesis. Thus, when pollen is mature, the outer wall of a spore body (tapetum) protein produced by genotype control; the inner walls of the gametophyte (pollen) cells control the production of the protein genotypes, which are identified from the role of the protein. Identification of the pollen on the pistil, the current dry-type stigma (stigma maturity without liquid discharge) was quite clear. For example, in Cruciferae and Compositae plants, stigma surface papillary single cell, which with a layer of pectin and cellulose in the wall of the cuticle is not continuous. Papillary cells in the development process, through the wall and cuticle secretion of some substances also form a thin film covering the surface, this film is the main component of proteins, which not only provides a benefit to "capture" the surface of sticky pollen, and with the recognition "receptors" features. When combined with the pollen wall protein occurred then "accept" or "reject" response. Pollen falls on the stigma, stigma water from the swollen, within minutes after exposure, the protein that is released from the pollen wall and stigma surface membrane protein binding, if it is a combination of affinity, pollen germination, the role of the enzyme, stigma cuticle is dissolved, the pollen tube into the stigma and style in the smooth growth. In the case of incompatible pollen tube growth and stagnation, or can not enter the stigma (sporophyte system control), or stop the growth of pollen tubes in the styles and rupture (gametophyte system control). Radish, cabbage, cosmos and sunflowers and other plants in the self-incompatibility in a few hours after pollination, stigma papilla-like cells that produce callose convex lens-like structure; in the mating pro-and no callose response. This reaction can callose as a test within a certain kinship affinity indicators. Pollen to the stigma of a fall germination, and also lead to stigma cells, papillary callose formation (top of the formation of grass plants in the pollen tube callose) This is the incompatibility response. Intraspecific and interspecific incompatibility incompatibility occur this reaction in sign between the two there are certain parental relationship; If neither of pollen germination, nor cause callose papilla cells showed reaction reflects the two parents is not between unrelated hybrid nature, which is often far different families hybridization between the performance of the situation. Pollination and fertilization in vitro 60 years have been the 20th century with the placenta can ovule of angiosperms, the pistil or ovary placed under conditions in vitro pollination and fertilization to achieve. In vitro pollination and fertilization technology in the breeding process may overcome the sexual reproduction as a self exists or hybrid incompatibility barriers means. And plant self-incompatibility barriers in the fertilization process, usually occurs in the stigma or style, that is the result of pollen and stigma recognition reaction tube growth was inhibited, can not enter the stigma or in the style that fertilization failure in growth arrest. Therefore, the possibility of using in vitro pollination of ovules successfully fertilized. This has been successfully tested in the genus Petunia. For example, self-incompatibility and the axillary flower petunia seat with a full fetal ovary ovules were cultured in vitro and taught to self-pollen. Results normal pollen tube growth, and finally the formation of a normal development of the embryo and endosperm of seeds. Obtained from the seeds of in vitro fertilization, the first generation of plants grown as its parent, is diploid, fertile and self-incompatibility and the. On the other hand, in pink, poppy, Solanaceae, and Gramineae plants try some of pollination and fertilization in vitro techniques to overcome hybrid incompatibility. Although many hybrid combinations can achieve fertilization, but failed to get a life force of seeds.
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Eggs and sperm are significant differences between what the individual?
According to "Encyclopedia of China" medical volume contains the human eggs visible, about 0.2 mm in diameter, is the largest human cells, and sperm count even if the length is only 0.06 mm, terms of volume comparison, only thousandths of eggs one. Since this relationship is far from the chance of their appearance, about one egg a month before discharge, and no time limit discharge of 200 million sperm at one time the public. Reproductive eggs also responsible for the mission, their difference is so poor why do the individual? We must first understand why the animals were divided into two sexes. Some people may say, is to limit the success rate when the spouse to maintain a stable number. Why let the sperm can be _select_ed at the location? The field of evolutionary biology is a major issue. There are many definitions of sexual way, here talking about the biological sexual reproduction has produced eggs, ovaries and other features of these large individual known as female gametes, and those that produce only sperm, pollen and other small gametes called it for the males.
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Fertilized egg implantation
6 to 7 days after fertilization, the zona pellucida after the disappearance of the late blastocyst gradually buy processes covered by the endometrium, said the fertilized egg implantation. To go through three processes 1. Positioning 2. Adhesion 3. Through Decay rapidly after implantation.
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Encyclopedia
shoujing Fertilization fertilization The process of sperm penetrating the egg. Surface contact with the egg from the sperm begin to penetrate into the egg, the egg pronucleus is fertilized with the sperm of the original fusion end.
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Medical Dictionary
Mature germ cells (sperm and eggs) with a new cell (zygote) process. Mature egg from the ovary discharged into the oviduct, sperm encounter at this time if it will combine with the sperm to become fertilized. If discharged within 24 hours of eggs and sperm can not meet and fertilization, which degradation of death. Sperm can survive in the reproductive tract 1 to 3 days, and can be maintained by the Sperm 1 to 2 days. Highly fertilized egg viability and genetic characteristics of both parents, if men and women of the reproductive tract is not smooth, sperm and eggs can not be met, it can not achieve fertilization (condoms, diaphragms and other contraceptive methods, and tubal ligation is based on this principle.) Fertilized egg in the uterus during the move to split and form a blastocyst, planted in the endometrium, the appropriate environmental conditions in the differentiation and development into a new individual. Artificial insemination is the quality of semen (the husband's or others) entered the woman's body, fertilizing, to solve some couples suffering from infertility, fertility problems. Human artificial insemination technique in 1890, first used by the United States, Dulai Johnson, then the user increasing. It is estimated that in the U.S. alone, about 5,000 to 10,000 babies born of artificial insemination. In 1983, China's first artificial insemination with frozen semen of infants born in Hunan.
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Fertilization (plant)
shoujing (zhiwu) Fertilization (plant) Fusion of two gametes into zygotes process. With the zygote develops into a new individual genetic parents. Fertilization is the central link of sexual reproduction. Higher plants and animals of the male and female parent (ie, male and female) of the genetic characteristics of chromosomes from a haploid sperm (plants) and eggs (plant) and spread to the offspring through fertilization. By the sperm and egg fusion produces a new individual, restoring as parent the same as twice the number of chromosomes, inherited the parent of both inherited the same time, the parents both the genetic material of the reorganization, there are likely to exhibit new traits. Therefore, the offspring produced by fertilization, the genetic characteristics of both the parental generation, but also the performance of a specific individual. Thus, fertilization is not only a continuation of the species in the maintenance of great significance, but also the biological evolution of an important factor. There are 3 basic ways: ① the same with reproduction (gametes with the same type); ② vary with reproductive (abnormal gametes with); ③ type of reproductive eggs (egg meet) (Figure 1 in different types of gametes fertilized morphological differentiation). Fertilization of the three forms of integration reflects the differentiation of the two gametes from the few to have a clear division of the evolutionary process. Different ways of fertilization with the integration of reproductive gametes in both the difference between a fixed size, which is the further differentiation of cell performance. For example, pine green algae in the genus, in a repeat of individuals to generate two kinds of bifurcation asci with, in an ascus with two flagella arising from the shape of a large gametes, and the other with the former produced in asci morphology similar and much smaller form gametes, female gametes called large and small as male gametes (Figure 4, the differences with pine reproduction.) Multicellular algae in the individual groups can be formed simultaneously both male and female gametes. Primitive cells from a male after numerous slender vertical division creates a lot of sperm with two flagella; eggs is increased by a female from the original cells, mature spherical, non-flagellated, swimming sperm swim to be Sheath coated eggs, sperm and egg fusion by a complete fertilization (Figure 5 Volvox reproductive egg-type). Algae and fungi and plants, the way of other sperm-egg fusion. For example, mold is a fungus in the water, the female organ ─ ─ oocysts at the end of the formation of hyphae in the oocysts in the development of the one or more eggs; sperm sperm-producing devices in the vicinity of oocyst production, sperm quantity, can not swim action. In fertilization, the sperm penetrate the device to grow the fertilized egg sac and sperm injection tube to be achieved next to fertilize the eggs (Figure 6 Saprolegnia reproductive egg-type). No algae green algae are separated from the water mold sex organs are similar, but the sperm active, mature eggs of only one oocyst. Sperm from
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Fertilization (animal)
shoujing (dongwu) Fertilization (animal) Fusion of egg and sperm into a zygote of the process. It is the basic characteristics of sexual reproduction is widespread in the animal sector. At the cellular level, the fertilized egg activation process, including adjustment and gender of the original fusion three main stages. Activation can be regarded as a starting point for individual development, mainly for the egg plasma membrane permeability changes in the efflux of cortical granules, fertilization membrane formation; adjustment occurred in the activated, is to ensure the normal fertilized eggs needed to split the first change; gender from the original fusion role to ensure that the genetic parents, and restore the diploid. At the molecular level, fertilization not only start the DNA replication, and activated eggs of the mRNA, rRNA and other genetic information to synthesize proteins required for embryonic development. Since the 20th century, fertilization research to explore the mechanisms of gender gametes. According to American scholar FR Lilly Research on Nereis and sea urchins, the first eggs that secrete sperm-related substances and acceptance, he called fertilin. Before and after the age of 40, another American scholar A. Taylor to fertilin biological, chemical and immunological characteristics of a series of work carried out to further emphasize the process of egg maturation effluent on the importance of fertilization. At the same time, the German scholar M. Hartmann believe that the sea urchin fertilization process, not only females with eggs can discharge factors, sperm can be discharged with male factor, the degree of match between the two determines the success or failure of fertilization. Soon, amphibians, found in the fertilization of eggs outside the film role. In 1956, China and other experimental cell scientist Zhu washing experiments in accordance gargarizans proposed secretion of eggs outside the film tube, as required for male and female gametes to achieve fertilization. In mammals, the CR 1951, Austin, Zhang Jue and sperm were also raised in the female reproductive tract must stay for some time, the ability to get penetration ─ ─ eggs were able to effectively to fertilize an egg. The discovery of sperm capacitation people to find the last egg in vitro fertilization is unsuccessful mammalian reason, so the higher mammals, and fertilization of human eggs to a new stage. Insemination in vivo fertilization and in vitro fertilization where the male and female broodstock mating, sperm transfer from male to female reproductive tract, fertilization gradually arrived at location (such as the uterus or fallopian tubes), where the fusion of sperm-egg encounter, saying in vivo fertilization. Where both sperm and eggs excreted, producing holes in the near or female fertilized in the water, said in vitro fertilization. The former occurred in higher animals such as reptiles, birds, mammals, some mollusks, insects and some fish and small amphibians. The latter is a common mode of reproduction of aquatic animals, such as some fish and some amphibians. Selfing and cross-fertilization is the most animals male and female allogeneic, male and female sexes are separate. Some animals are male and female with the body, the same individual produces both eggs and also produce sperm. In hermaphroditic animals, some of selfing, that is the same individual sperm and egg fused, such as tapeworm; there is still cross-fertilization, that is, individuals of two different sperm and egg combine, such as earthworms. Single sperm fertilization and polyspermy usually, only one sperm into the egg to complete fertilization, said the single-sperm fertilization, such as coelenterates, echinoderms, annelids, bony fish, amphibians and mammals tailless animals. Once these eggs and sperm exposed to immediately activated and produce a series of corresponding changes to prevent other sperm into the egg. If the maturity of the egg inappropriate because of other reasons, and have more than one kind of sperm into the egg, the so-called pathological polyspermy, the cleavage is not normal, abnormal embryonic development, sooner or later will return prematurely mourning. Some eggs in