Megasporogenesis/class 12 biology
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it is about the megagametogenesis and development of female gametophytes. it is helpful for intermediate biology students.
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Female gametophyte
The document summarizes the development of the female gametophyte in flowering plants. A diploid megaspore mother cell in the nucellus of an ovule undergoes meiosis to form four haploid megaspores arranged in a linear tetrad. The lower chalazal megaspore develops into the functional female gametophyte through three rounds of mitotic division, forming an eight-nucleate, seven-celled structure called the embryo sac containing an egg cell, synergid cells, and antipodal cells with a secondary nucleus formed by fusion of two polar nuclei.
Female gametophytes - Embryology
This document summarizes the structure and development of the female gametophyte in flowering plants. It notes that the female gametophyte, also called the embryo sac, develops from a megaspore mother cell into a usually seven-celled, eight-nucleate structure consisting of three antipodal cells, one central cell with two polar nuclei, two synergid cells, and one egg cell. Megasporogenesis involves meiotic divisions of the megaspore mother cell to form a linear tetrad of megaspores, with one functional megaspore developing into the embryo sac through mitotic divisions that result in the characteristic cell types and nuclei.
Megasporogenesis by vimal priya
The document discusses the structure and development of the ovule and female gametophyte (embryo sac) in flowering plants. It describes the ovule as containing the megasporangium, which produces megaspores through megasporogenesis. The megaspore mother cell undergoes meiosis to form four megaspores, with one developing into the embryo sac. The embryo sac contains three antipodal cells at the base, two synergid cells and one egg cell at the micropylar end, and two nuclei that fuse at the center to form the central cell. The document also classifies different ovule types and embryo sac development patterns, such as monosporic, bisporic and tetras
Cleavage by Tauqeer Ahmad
The document summarizes the process of cleavage in early embryonic development. It describes how the zygote undergoes rapid cell divisions called cleavage to form a solid ball of cells called a morula. The morula then develops a fluid filled cavity called a blastocoel, forming the blastocyst stage. Within the blastocyst, the cells arrange into two layers - an inner cell mass that will become the embryo, and an outer trophoblast layer that will provide nutrition and allow implantation in the uterus.
Female gametophyte
This document summarizes the development of the female gametophyte in angiosperms. It begins with an introduction to the megaspore mother cell and its development into the female gametophyte through meiosis. There are three main types of female gametophytes - monosporic, bisporic, and tetrasporic - which are distinguished by the number of megaspores involved. A monosporic gametophyte develops from a single megaspore, while bisporic and tetrasporic involve two and four megaspores, respectively. Examples of each type are provided, including the common Polygonum type of monosporic gametophyte and the Allium and
Megasporangium
This document discusses megasporangium, or ovules, including their types and integuments. It begins by introducing megasporangium and its components. It then describes the six types of ovules classified based on micropyle position: orthotropous, anatropous, hemitropous, campylotropous, amphitropous, and circinotropous. Next, it provides details on each type. Finally, it discusses integuments, which are usually one or two layers and can be unitegmic or bitegmic depending on the plant family. Integuments may also include an aril or become fleshy.
Types of embryo sac
The document describes the structure and development of three types of embryo sacs:
1) Monosporic embryo sacs develop from a single megaspore that undergoes three nuclear divisions without cell wall formation, resulting in an eight-nucleated sac with haploid nuclei.
2) Bisporic embryo sacs form when one cell of the megaspore dyad develops while the other degenerates, with each nucleus dividing twice to create the eight-nucleated sac.
3) Tetrasporic embryo sacs form when the four megaspore nuclei remain in a single cell (coenocyte) and all participate in embryo sac formation.
Megasporogenesis types and development of female gametophyte
Megasporogenesis types and development of female gametophyteGovt. Degree College for Women (A), Begumpet, Hyderabad, Telangana
This document summarizes megasporogenesis and megagametogenesis in angiosperms. Megasporogenesis involves the development of a megaspore mother cell from the nucellus tissue, which undergoes meiosis to form four megaspores. One megaspore develops into the embryo sac through mitotic divisions, while the other three degenerate. The embryo sac then matures during megagametogenesis to form the seven-celled, eight-nucleate structure containing the egg cell. Various patterns of megasporogenesis and different embryo sac types are described.Recommended
Female gametophyte
The document summarizes the development of the female gametophyte in flowering plants. A diploid megaspore mother cell in the nucellus of an ovule undergoes meiosis to form four haploid megaspores arranged in a linear tetrad. The lower chalazal megaspore develops into the functional female gametophyte through three rounds of mitotic division, forming an eight-nucleate, seven-celled structure called the embryo sac containing an egg cell, synergid cells, and antipodal cells with a secondary nucleus formed by fusion of two polar nuclei.
Female gametophytes - Embryology
This document summarizes the structure and development of the female gametophyte in flowering plants. It notes that the female gametophyte, also called the embryo sac, develops from a megaspore mother cell into a usually seven-celled, eight-nucleate structure consisting of three antipodal cells, one central cell with two polar nuclei, two synergid cells, and one egg cell. Megasporogenesis involves meiotic divisions of the megaspore mother cell to form a linear tetrad of megaspores, with one functional megaspore developing into the embryo sac through mitotic divisions that result in the characteristic cell types and nuclei.
Megasporogenesis by vimal priya
The document discusses the structure and development of the ovule and female gametophyte (embryo sac) in flowering plants. It describes the ovule as containing the megasporangium, which produces megaspores through megasporogenesis. The megaspore mother cell undergoes meiosis to form four megaspores, with one developing into the embryo sac. The embryo sac contains three antipodal cells at the base, two synergid cells and one egg cell at the micropylar end, and two nuclei that fuse at the center to form the central cell. The document also classifies different ovule types and embryo sac development patterns, such as monosporic, bisporic and tetras
Cleavage by Tauqeer Ahmad
The document summarizes the process of cleavage in early embryonic development. It describes how the zygote undergoes rapid cell divisions called cleavage to form a solid ball of cells called a morula. The morula then develops a fluid filled cavity called a blastocoel, forming the blastocyst stage. Within the blastocyst, the cells arrange into two layers - an inner cell mass that will become the embryo, and an outer trophoblast layer that will provide nutrition and allow implantation in the uterus.
Female gametophyte
This document summarizes the development of the female gametophyte in angiosperms. It begins with an introduction to the megaspore mother cell and its development into the female gametophyte through meiosis. There are three main types of female gametophytes - monosporic, bisporic, and tetrasporic - which are distinguished by the number of megaspores involved. A monosporic gametophyte develops from a single megaspore, while bisporic and tetrasporic involve two and four megaspores, respectively. Examples of each type are provided, including the common Polygonum type of monosporic gametophyte and the Allium and
Megasporangium
This document discusses megasporangium, or ovules, including their types and integuments. It begins by introducing megasporangium and its components. It then describes the six types of ovules classified based on micropyle position: orthotropous, anatropous, hemitropous, campylotropous, amphitropous, and circinotropous. Next, it provides details on each type. Finally, it discusses integuments, which are usually one or two layers and can be unitegmic or bitegmic depending on the plant family. Integuments may also include an aril or become fleshy.
Types of embryo sac
The document describes the structure and development of three types of embryo sacs:
1) Monosporic embryo sacs develop from a single megaspore that undergoes three nuclear divisions without cell wall formation, resulting in an eight-nucleated sac with haploid nuclei.
2) Bisporic embryo sacs form when one cell of the megaspore dyad develops while the other degenerates, with each nucleus dividing twice to create the eight-nucleated sac.
3) Tetrasporic embryo sacs form when the four megaspore nuclei remain in a single cell (coenocyte) and all participate in embryo sac formation.
Megasporogenesis types and development of female gametophyte
Megasporogenesis types and development of female gametophyteGovt. Degree College for Women (A), Begumpet, Hyderabad, Telangana
This document summarizes megasporogenesis and megagametogenesis in angiosperms. Megasporogenesis involves the development of a megaspore mother cell from the nucellus tissue, which undergoes meiosis to form four megaspores. One megaspore develops into the embryo sac through mitotic divisions, while the other three degenerate. The embryo sac then matures during megagametogenesis to form the seven-celled, eight-nucleate structure containing the egg cell. Various patterns of megasporogenesis and different embryo sac types are described.Bio 130 ovule dev. ist sem 2013 2014
1) The ovary contains a cavity lined with epidermal cells. Ovules develop from these epidermal cells and are contained within the ovary cavity, attached by a stalk called the funiculus.
2) The ovule has four main parts: the nucellus at the center containing sporogenous cells, one or two integuments surrounding the nucellus, the funiculus stalk connecting the ovule to the placenta, and the chalaza where the nucellus, integuments and funiculus merge.
3) A megaspore mother cell within the nucellus undergoes meiosis to form a megaspore, which
Amnion & early development
- Mammalian eggs are among the smallest in the animal kingdom. After sperm entry, the male and female pronuclei fuse without forming a zygote nucleus. Cleavages are slow, about 12-24 hours apart.
- Following the third cleavage, the blastomeres compact into a ball and further divide. The morula forms, with an inner cell mass and outer trophoblast cells. Cavitation occurs as trophoblast cells secrete fluid.
- The blastocyst implants in the uterus. The inner cell mass forms the embryo and associated structures, while trophoblast cells form the chorion and fetal part of the placenta. Gastrulation begins through a primitive streak, forming
Blastulation
Blastulation refers to the process in early embryonic development where the zygote undergoes rapid cell divisions through cleavage to form a solid ball of cells called a morula. The morula then develops a fluid-filled cavity, forming a structure called a blastocyst composed of an inner cell mass and outer layer of trophoblast cells. The blastocyst undergoes further differentiation, with the inner cell mass forming the embryo and extraembryonic tissues such as the amnion, yolk sac, and allantois developing to support the growth and development of the embryo.
Twins pp
This document discusses the development of identical and non-identical twins from conception through birth. It begins by explaining that identical twins come from one zygote that splits, while non-identical twins develop from two separate eggs fertilized by two different sperm. It then describes the three ways identical twins can form based on shared placenta and amniotic sac formation. Risks and complications of multiple pregnancies are outlined for both mother and babies. The document concludes by addressing how to determine a multiple pregnancy, breastfeed twins, and deliver twins.
Cleavage
Cleavage is the process of rapid, synchronous cell divisions that occur after fertilization and before the mid-blastula transition. It involves the division of the zygote into increasingly smaller blastomeres through mitosis without cell growth. The planes and patterns of cleavage are determined by the distribution of yolk and cytoplasmic movements in the egg. This results in either complete or partial cleavage, forming a hollow ball of cells called a blastula. The transition to asynchronous cell cycles and zygotic transcription marks the mid-blastula stage.
Developmental biology
1) Cleavage is the first stage of embryo development, where the single-celled egg undergoes rapid mitotic cell divisions to form a compact mass of cells called a morula.
2) The egg undergoes four specific cleavage planes - meridional, vertical, equatorial, and lattitudinal - to develop from a two-celled stage to a thirty-two celled stage.
3) After the thirty-two celled stage, the cells continue dividing rapidly and forming a ball shape called a morula or "mulberry stage".
Early Vertebrate development
The four main processes of early development are fertilization, cleavage, gastrulation, and organogenesis. Fertilization involves the combination of an egg and sperm cell to form a zygote. Cleavage is the rapid cell division of the zygote to form a hollow ball of cells called a blastula. Gastrulation rearranges the cells of the blastula into three germ layers - ectoderm, mesoderm, and endoderm. Finally, during organogenesis these germ layers develop into the internal organs of the organism.
Cleavage
This document summarizes key aspects of mammalian cleavage. It begins by defining cleavage as the rapid cell divisions that occur after fertilization. It then describes different patterns of mammalian cleavage based on cleavage furrows, fate of germ layers, and cell arrangement. The importance of cleavage in generating cells for differentiation and increasing the nucleus to cytoplasm ratio is highlighted. Key stages of early embryonic development including fertilization, cleavage, gastrulation and organogenesis are outlined. The document concludes by detailing the specific cell divisions and structures that arise during cleavage and blastula formation in mammals.
عرض اجنة
The document discusses the process of human development from fertilization through the first week. It explains that fertilization occurs when a sperm penetrates an ovum in the fallopian tube, forming a zygote with 46 chromosomes. The zygote then undergoes rapid cell division as it is transported down the fallopian tube by cilia motion. By the end of the first week, the embryo has divided into multiple identical cells or blastomeres.
Cdocumentsandsettingsayetmydocumentsplantmorpholabactivitiesch26 091129203156...
Cdocumentsandsettingsayetmydocumentsplantmorpholabactivitiesch26 091129203156...Muhammad Fahad Saleh
This document discusses plant tissues and how they are organized in plant structures like stems, roots, and leaves. It describes the basic tissue types found in plants like parenchyma, collenchyma and sclerenchyma, as well as complex tissues like xylem, phloem and epidermis. The chapter also examines how plant tissues develop and are arranged differently between monocots and dicots.Megasporogenesis
Megaspores are a type of spore found in heterosporous plants that germinate into a female gametophyte containing egg cells. Megasporogenesis is the formation of megaspores inside the ovule of seed plants. A diploid cell called the megasporocyte undergoes meiosis to form four haploid megaspores, though typically only one develops into a megagametophyte while the others disintegrate. This process of megaspore formation inside the ovule leads to the development of the embryo sac within the mature megagametophyte.
Cleavage and blastulation
Animal Development, Blastula, Morula, Drosophila,Frog,Chick,Mammals, Pattern of Cleavage and Blastula formation .
Life History And Embryogenesis
The document summarizes key stages in animal embryogenesis including fertilization, cleavage, blastulation, gastrulation, and neurulation. During fertilization, a sperm fuses with an egg to form a zygote. Cleavage involves cell divisions that form a ball of cells or blastula. Gastrulation establishes the three germ layers through cell movements. It occurs differently depending on egg characteristics like yolk content. Neurulation transforms the gastrula into a neurula by forming the neural tube from ectoderm.
Gametogenesis in plants
Gametogenesis in plants
Gametogenesis: Formation of Male Gametes
Gametogenesis leading to the formation of male gametes in angiosperms occurs in two stages:
-Microsporogenesis
-Microgametogenesis
Gametogenesis: Formation of Female Gametes
Gametogenesis in angiosperms to form the female gametes, like the male gametes, occurs in two stages:
-Megasporogenesis
-Megagametogenesis
Dicot embryogenesis
After double fertilization and triple fusion, the zygote secretes a cellulose wall and divides into two cells - an upper embryonal cell and lower suspensor cell. The embryonal cell divides into eight octant cells which then divide further, forming a surface layer of dermatogen cells and an inner embryonal mass. The dermatogens and embryonal mass cells continue dividing and differentiating to form the various parts of the embryo, including the plumule, cotyledons, radicle, and hypocotyledons.
Somite formation
Somites are bilaterally paired segments of paraxial mesoderm that form along the embryonic axis and give rise to important structures. Somites subdivide into sclerotomes, myotomes and dermatomes that form vertebrae, ribs, muscle, tendons and skin. Somite formation depends on a "clock mechanism" where paraxial mesoderm segments into somites according to their position in a regulated process. Within each somite, cells are specified based on location and retain flexibility before differentiating into somite-derived tissues through epithelialization and mesenchymal transformation processes.
Echinoderm embryology
Echinoderm embryology discusses the early development of sea urchins. Sea urchins exhibit radial holoblastic cleavage, with the first few cleavages perpendicular to each other and forming a radial pattern. During blastulation, the 128-cell embryo forms a hollow sphere with a central cavity. Gastrulation in sea urchins begins with primary mesenchyme cells ingressing from the vegetal plate, followed by invagination of the vegetal plate to form the archenteron. Secondary mesenchyme cells then ingress and disperse throughout the blastocoel.
Types of endosperm
Different types of Endosperm present in Plant life cycles are beautifully described by Rashmi R. Rehman of Gauhati University
Reproduction Notes
The document summarizes key concepts about cell reproduction, mitosis, meiosis, and human reproductive systems. It discusses how all cells come from preexisting cells and undergo cell division. Mitosis and meiosis are described as processes that allow for cell growth and reproduction. Meiosis results in gamete formation with half the normal number of chromosomes. The male and female reproductive systems are compared, outlining gamete production and hormonal regulation of the process.
Embryology and reproduction
1. Fertilization occurs when a sperm cell fuses with an egg cell to form a zygote. The zygote then undergoes cleavage and develops into a morula, blastula, and then a gastrula with three germ layers.
2. The embryo develops organs and tissues during the first trimester and is then referred to as a fetus. It continues to grow and develop throughout the second and third trimesters.
3. The male and female reproductive systems produce and transport gametes through various glands and structures. In females, eggs mature in the ovaries and travel through the fallopian tubes, while in males sperm mature in the testes and epididymis and
Reproduction in Cycas
description of different types of reproductive organs, developmental stages and process of reproduction in Cycas. Various internet sources have been used.
Megasporogenesis
Megasporogenesis is the formation of megaspores in the megasporangium. This involves the development of the megaspore mother cell from the archesporial cell, which then undergoes meiosis to form four megaspores. One megaspore survives to form the embryo sac, which contains eight nuclei that develop into either a seven-celled structure in monosporic development types or other structures depending on the type of development. Ovules vary in structure depending on factors like the number of integuments and position of the micropyle.
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Bio 130 ovule dev. ist sem 2013 2014
1) The ovary contains a cavity lined with epidermal cells. Ovules develop from these epidermal cells and are contained within the ovary cavity, attached by a stalk called the funiculus.
2) The ovule has four main parts: the nucellus at the center containing sporogenous cells, one or two integuments surrounding the nucellus, the funiculus stalk connecting the ovule to the placenta, and the chalaza where the nucellus, integuments and funiculus merge.
3) A megaspore mother cell within the nucellus undergoes meiosis to form a megaspore, which
Amnion & early development
- Mammalian eggs are among the smallest in the animal kingdom. After sperm entry, the male and female pronuclei fuse without forming a zygote nucleus. Cleavages are slow, about 12-24 hours apart.
- Following the third cleavage, the blastomeres compact into a ball and further divide. The morula forms, with an inner cell mass and outer trophoblast cells. Cavitation occurs as trophoblast cells secrete fluid.
- The blastocyst implants in the uterus. The inner cell mass forms the embryo and associated structures, while trophoblast cells form the chorion and fetal part of the placenta. Gastrulation begins through a primitive streak, forming
Blastulation
Blastulation refers to the process in early embryonic development where the zygote undergoes rapid cell divisions through cleavage to form a solid ball of cells called a morula. The morula then develops a fluid-filled cavity, forming a structure called a blastocyst composed of an inner cell mass and outer layer of trophoblast cells. The blastocyst undergoes further differentiation, with the inner cell mass forming the embryo and extraembryonic tissues such as the amnion, yolk sac, and allantois developing to support the growth and development of the embryo.
Twins pp
This document discusses the development of identical and non-identical twins from conception through birth. It begins by explaining that identical twins come from one zygote that splits, while non-identical twins develop from two separate eggs fertilized by two different sperm. It then describes the three ways identical twins can form based on shared placenta and amniotic sac formation. Risks and complications of multiple pregnancies are outlined for both mother and babies. The document concludes by addressing how to determine a multiple pregnancy, breastfeed twins, and deliver twins.
Cleavage
Cleavage is the process of rapid, synchronous cell divisions that occur after fertilization and before the mid-blastula transition. It involves the division of the zygote into increasingly smaller blastomeres through mitosis without cell growth. The planes and patterns of cleavage are determined by the distribution of yolk and cytoplasmic movements in the egg. This results in either complete or partial cleavage, forming a hollow ball of cells called a blastula. The transition to asynchronous cell cycles and zygotic transcription marks the mid-blastula stage.
Developmental biology
1) Cleavage is the first stage of embryo development, where the single-celled egg undergoes rapid mitotic cell divisions to form a compact mass of cells called a morula.
2) The egg undergoes four specific cleavage planes - meridional, vertical, equatorial, and lattitudinal - to develop from a two-celled stage to a thirty-two celled stage.
3) After the thirty-two celled stage, the cells continue dividing rapidly and forming a ball shape called a morula or "mulberry stage".
Early Vertebrate development
The four main processes of early development are fertilization, cleavage, gastrulation, and organogenesis. Fertilization involves the combination of an egg and sperm cell to form a zygote. Cleavage is the rapid cell division of the zygote to form a hollow ball of cells called a blastula. Gastrulation rearranges the cells of the blastula into three germ layers - ectoderm, mesoderm, and endoderm. Finally, during organogenesis these germ layers develop into the internal organs of the organism.
Cleavage
This document summarizes key aspects of mammalian cleavage. It begins by defining cleavage as the rapid cell divisions that occur after fertilization. It then describes different patterns of mammalian cleavage based on cleavage furrows, fate of germ layers, and cell arrangement. The importance of cleavage in generating cells for differentiation and increasing the nucleus to cytoplasm ratio is highlighted. Key stages of early embryonic development including fertilization, cleavage, gastrulation and organogenesis are outlined. The document concludes by detailing the specific cell divisions and structures that arise during cleavage and blastula formation in mammals.
عرض اجنة
The document discusses the process of human development from fertilization through the first week. It explains that fertilization occurs when a sperm penetrates an ovum in the fallopian tube, forming a zygote with 46 chromosomes. The zygote then undergoes rapid cell division as it is transported down the fallopian tube by cilia motion. By the end of the first week, the embryo has divided into multiple identical cells or blastomeres.
Cdocumentsandsettingsayetmydocumentsplantmorpholabactivitiesch26 091129203156...
Cdocumentsandsettingsayetmydocumentsplantmorpholabactivitiesch26 091129203156...Muhammad Fahad Saleh
This document discusses plant tissues and how they are organized in plant structures like stems, roots, and leaves. It describes the basic tissue types found in plants like parenchyma, collenchyma and sclerenchyma, as well as complex tissues like xylem, phloem and epidermis. The chapter also examines how plant tissues develop and are arranged differently between monocots and dicots.Megasporogenesis
Megaspores are a type of spore found in heterosporous plants that germinate into a female gametophyte containing egg cells. Megasporogenesis is the formation of megaspores inside the ovule of seed plants. A diploid cell called the megasporocyte undergoes meiosis to form four haploid megaspores, though typically only one develops into a megagametophyte while the others disintegrate. This process of megaspore formation inside the ovule leads to the development of the embryo sac within the mature megagametophyte.
Cleavage and blastulation
Animal Development, Blastula, Morula, Drosophila,Frog,Chick,Mammals, Pattern of Cleavage and Blastula formation .
Life History And Embryogenesis
The document summarizes key stages in animal embryogenesis including fertilization, cleavage, blastulation, gastrulation, and neurulation. During fertilization, a sperm fuses with an egg to form a zygote. Cleavage involves cell divisions that form a ball of cells or blastula. Gastrulation establishes the three germ layers through cell movements. It occurs differently depending on egg characteristics like yolk content. Neurulation transforms the gastrula into a neurula by forming the neural tube from ectoderm.
Gametogenesis in plants
Gametogenesis in plants
Gametogenesis: Formation of Male Gametes
Gametogenesis leading to the formation of male gametes in angiosperms occurs in two stages:
-Microsporogenesis
-Microgametogenesis
Gametogenesis: Formation of Female Gametes
Gametogenesis in angiosperms to form the female gametes, like the male gametes, occurs in two stages:
-Megasporogenesis
-Megagametogenesis
Dicot embryogenesis
After double fertilization and triple fusion, the zygote secretes a cellulose wall and divides into two cells - an upper embryonal cell and lower suspensor cell. The embryonal cell divides into eight octant cells which then divide further, forming a surface layer of dermatogen cells and an inner embryonal mass. The dermatogens and embryonal mass cells continue dividing and differentiating to form the various parts of the embryo, including the plumule, cotyledons, radicle, and hypocotyledons.
Somite formation
Somites are bilaterally paired segments of paraxial mesoderm that form along the embryonic axis and give rise to important structures. Somites subdivide into sclerotomes, myotomes and dermatomes that form vertebrae, ribs, muscle, tendons and skin. Somite formation depends on a "clock mechanism" where paraxial mesoderm segments into somites according to their position in a regulated process. Within each somite, cells are specified based on location and retain flexibility before differentiating into somite-derived tissues through epithelialization and mesenchymal transformation processes.
Echinoderm embryology
Echinoderm embryology discusses the early development of sea urchins. Sea urchins exhibit radial holoblastic cleavage, with the first few cleavages perpendicular to each other and forming a radial pattern. During blastulation, the 128-cell embryo forms a hollow sphere with a central cavity. Gastrulation in sea urchins begins with primary mesenchyme cells ingressing from the vegetal plate, followed by invagination of the vegetal plate to form the archenteron. Secondary mesenchyme cells then ingress and disperse throughout the blastocoel.
Types of endosperm
Different types of Endosperm present in Plant life cycles are beautifully described by Rashmi R. Rehman of Gauhati University
Reproduction Notes
The document summarizes key concepts about cell reproduction, mitosis, meiosis, and human reproductive systems. It discusses how all cells come from preexisting cells and undergo cell division. Mitosis and meiosis are described as processes that allow for cell growth and reproduction. Meiosis results in gamete formation with half the normal number of chromosomes. The male and female reproductive systems are compared, outlining gamete production and hormonal regulation of the process.
Embryology and reproduction
1. Fertilization occurs when a sperm cell fuses with an egg cell to form a zygote. The zygote then undergoes cleavage and develops into a morula, blastula, and then a gastrula with three germ layers.
2. The embryo develops organs and tissues during the first trimester and is then referred to as a fetus. It continues to grow and develop throughout the second and third trimesters.
3. The male and female reproductive systems produce and transport gametes through various glands and structures. In females, eggs mature in the ovaries and travel through the fallopian tubes, while in males sperm mature in the testes and epididymis and
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Megasporogenesis is the formation of megaspores in the megasporangium. This involves the development of the megaspore mother cell from the archesporial cell, which then undergoes meiosis to form four megaspores. One megaspore survives to form the embryo sac, which contains eight nuclei that develop into either a seven-celled structure in monosporic development types or other structures depending on the type of development. Ovules vary in structure depending on factors like the number of integuments and position of the micropyle.
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The document summarizes the structure and types of embryo sacs in angiosperms. It describes that a typical embryo sac is a 7-celled, 8-nucleated structure derived from a megaspore due to megagametogenesis. It usually possesses an egg apparatus with an egg cell and synergids, antipodals, and a central cell with polar nuclei. Various types of embryo sacs are described based on the number of megaspores that develop, including monosporic, bisporic, and tetrasporic embryo sacs. The structures and development of different specific types like Polygonum and Oenothera are explained.
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The document describes different types of embryo sacs (female gametophytes) in plants. It discusses the classification of embryo sacs based on the number of megaspores involved in development and the number and organization of nuclei. The main types described are monosporic (e.g. Polygonum and Oenothera), bisporic, and tetrasporic (e.g. Adoxa, Plumbago, Penaea, Peperomia, Drusa, Fritillaria, and Plumbagella). Each type has distinct features in megaspore development and nuclear divisions and organization in the mature embryo sac.
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The document discusses the formation and types of embryo sacs in flowering plants. It begins by defining the embryo sac as the female gametophyte found within the ovule. It then describes the two main stages of embryo sac formation: megaspore formation through meiosis, and megagametogenesis where the haploid megaspore develops into the embryo sac through mitosis. There are three main classifications of embryo sacs based on the number of megaspores involved: monosporic, bisporic, and tetrasporic. The most common type is the monosporic Polygonum embryo sac, which has 8 nuclei organized into specific cell types.
Embryology of Angiosperm, Development of Flower and Reproduction.pptx
1. The document describes the structure and development of male and female reproductive organs in angiosperms. It discusses the formation of microspores through microsporogenesis and megaspores through megasporogenesis.
2. Key parts of the flower are described like stamen, anther, and carpels. Processes like microsporogenesis and development of pollen grains and male gametophyte are summarized.
3. Structure of ovule, types of ovules and development of embryo sac through megasporogenesis are highlighted. Fertilization process where pollen lands on stigma and pollen tube enters embryo sac is briefly explained.
EMBRYOLOGY.pptx
This document discusses human embryology and development from fertilization through birth. It describes the embryonic and fetal periods, the stages of development including fertilization, cleavage, gastrulation, and organogenesis. Key events like formation of the three germ layers and development of the placenta, amnion, chorion, and allantois are summarized. The roles of hormones and growth of the major organs by the third trimester are highlighted. Birth and the role of oxytocin in labor are briefly mentioned.
Embrosac-2-18.pdf. types of embrosac. monosporic
The document describes the development and types of the female gametophyte or embryo sac in plants. It discusses that the functional megaspore undergoes mitotic divisions to form the mature embryo sac containing various cell types including the egg cell. Embryo sacs are classified as monosporic, bisporic or tetrasporic depending on the number of megaspores involved. Specific types of each include Polygonum, Oenothera, Allium and Endymion. The tetrasporic embryo sacs further differ in nuclear organization and divisions, with examples like Adoxa, Plumbago and Penaea types described.
Megasporogenesis by Anurag yadav
MEGASPOROGENESIS, DEVELOPMENT OF EMBRYO SAC , SUBCELLULAR DETAILS OF CONSTITUENT CELLS AND THEIR FUNCTION, MAJOR TYPES
Development of frog/ embryogenesis
1. The development of frog consists of copulation, spawning, fertilization, cleavage, blastulation, gastrulation, and post-embryonic development.
2. During gastrulation, epiboly, imboly, contraction of the blastopore, and involution occur, forming the three germ layers - ectoderm, mesoderm, and endoderm.
3. Post-embryonic development includes neurogenesis forming the neural tube, notogenesis forming the notochord, and coelom formation separating the mesoderm into three layers.
Sexual reproduction in angiosperm(microsporogenesis)
This document summarizes the process of microsporogenesis and microgametogenesis in angiosperms. Microsporogenesis involves the formation of microspores (pollen grains) from microspore mother cells within the anther through meiosis. The anther contains four layers surrounding the pollen sacs: epidermis, endothecium, middle layer, and tapetum. During microgametogenesis, the pollen grain germinates and its nucleus divides to form a vegetative cell and generative cell. The generative cell then divides into two sperm cells that are delivered to the female gametophyte via a pollen tube.
Sporogenesis, Gametogenesis, Fertilization & Seed Development.pdf
Sporogenesis, Gametogenesis, Fertilization & Seed Development
Seed Science and Technology
K. Vanangamudi
Sexual reproduction in flowering plants
- The document discusses the structures and processes involved in plant fertilization before fertilization occurs, including the development of male and female reproductive structures in flowers.
- It describes in detail the structures of the stamen (pollen sac and pollen grain), pistil, ovule, and embryo sac. Key processes like microsporogenesis, megaspore formation, and double fertilization are summarized.
- Various mechanisms of pollination like autogamy, geitonogamy, xenogamy and biotic/abiotic pollination agents are covered. Outbreeding devices in plants to promote cross-pollination and prevent inbreeding are also mentioned.
Types of Embryosacs KR.pptx
This document describes the different types of embryo sacs, which are classified based on the number of megaspores that develop into the embryo sac. There are three main types: monosporic (develops from one megaspore), bisporic (develops from two megaspores), and tetrasporic (develops from four megaspores). Within each type there are further sub-classifications based on the organization of nuclei in the mature embryo sac. The document provides examples for each sub-classification, such as the Polygonum and Oenothera types for monosporic, the Allium and Endymion types for bisporic, and the Plumbago, Adoxa,
Sporogenesis and gametogenesis
This document summarizes the processes of sporogenesis and gametogenesis in plants. Sporogenesis involves the production of microspores and megaspores, which occurs through microsporogenesis in anthers and megasporogenesis in ovules. Gametogenesis then produces the male and female gametes. Microgametogenesis occurs through pollen development and tube growth, producing two sperm cells. Megagametogenesis involves mitotic divisions within the megaspore producing an embryo sac containing an egg cell. Fertilization occurs when a sperm fuses with the egg cell, forming a zygote, and the other sperm fuses with the secondary nucleus.
An introduction to embryology of angiosperms
This document provides an overview of angiosperm embryology, including:
- Sporogenesis and gametogenesis, which produce haploid spores and gametes from diploid tissues in the anther and ovary.
- Anther and ovule development, including formation of protective layers and meiotic divisions producing microspores and megaspores.
- Microgametogenesis and megagametogenesis, where spores develop into pollen grains or the embryo sac containing eggs.
- Double fertilization, where one sperm fuses with the egg and the other with polar nuclei to form the triploid endosperm.
- Embryo and seed development from the zygote and endos
Embryonic development SlideShare.
1. Cleavage is the early mitotic divisions of the zygote that forms a hollow, multicellular blastocyst. The zygote undergoes a series of cleavages, reducing cell size and increasing metabolic rate.
2. Blastulation is the formation of the blastocyst from the morula. The outer cells of the morula form the trophoblast, which absorbs uterine fluid to form a blastocyst cavity. The inner cells remain as the embryoblast.
3. Implantation occurs when the blastocyst attaches to the uterine wall between 7-10 days after fertilization. The trophoblast cells invade the endometrium and secrete enzymes, forming
Similar to Megasporogenesis/class 12 biology (20)
Embryology of Angiosperm, Development of Flower and Reproduction.pptx
Embryology of Angiosperm, Development of Flower and Reproduction.pptx
Sexual reproduction in angiosperm(microsporogenesis)
Sexual reproduction in angiosperm(microsporogenesis)
Sporogenesis, Gametogenesis, Fertilization & Seed Development.pdf
Sporogenesis, Gametogenesis, Fertilization & Seed Development.pdf
More from Dambar Khatri
Migration in fishes/class11 biology
Migration in fishes generally refers to the periodic movement of fish from one place to another for purposes such as food, shelter, breeding, or protection. There are several types of migration including diadromous migration where fish move between freshwater and seawater for breeding, potamodromous migration within freshwater systems, and oceanodromous migration confined to ocean waters for food. Some key advantages of migration for fish are that it allows them to find safe shelter, ample food sources, better conditions for reproduction, and helps them to adapt to new environments while avoiding competition.
Description of family solanaceae in semi technical term/class11 bilogy
This document summarizes the characteristics of the Solanaceae family of plants. It describes that the family includes over 2,200 species distributed mainly in tropical and temperate regions. Most members are herbs, shrubs, or trees that have alternate leaves, cymose inflorescences, and berries or capsules as fruits. Economically important plants in this family include potatoes, tomatoes, chilies, tobacco, and belladonna, which is used to extract atropine.
Description of family fabaceae
This document summarizes the key characteristics of plants in the Fabaceae family, also known as legumes. It describes their distribution in temperate and subtropical regions. Most are annual or perennial herbs, shrubs, or trees with branched taproots containing nitrogen-fixing nodules. Their leaves are alternately arranged and compound, stems are branched, and flowers are usually racemose with five fused sepals and five fused petals. Economically, they are important as vegetables, pulses, and for their ability to fix nitrogen in soil.
Development of embryo/class12 biology
The document summarizes the development of dicot and monocot embryos. It begins by defining embryogenesis as the process after fertilization that produces a fully developed plant embryo. It then describes the development of dicot embryos, starting with the zygote dividing into two cells, one forming the suspensor and one the embryo proper. The embryo cell divides further to form the octant stage with eight cells that develop into various embryo parts. For monocot embryos, the zygote also divides into two cells but the basal cell does not divide further and forms the suspensor directly while the embryo cell divides to form the plumule, hypocotyl, and radicle.
Pollination/class 12 biology
This document discusses different types of pollination in plants. It describes self-pollination, which can occur through autogamy within a flower or geitonogamy between different flowers of the same plant. Cross-pollination involves the transfer of pollen between different plants and can be facilitated by biotic agents like insects, birds, or abiotic factors like wind and water. The document provides examples of different pollination types and notes advantages and disadvantages of self-pollination versus cross-pollination.
Floral formula and floral diagram
the floral formula tells us about the nature of flowers. the floral diagram represents the plan of arrangements of floral whorl in relation to the mother axis.
Animal behavior/ orientation/taxes
this ppt slide consists of the definition of orientation, types of taxis. these slides help students to understand taxis' behavior in an easy way.
Schon's models of curriculum dissemination
Schon identified three models of curriculum dissemination:
1. The center-periphery model involves dissemination controlled from a central source spreading outward.
2. The proliferation of centres model establishes primary and secondary centers that both support and expand dissemination.
3. The shifting- centres method emerges from social movements and lacks clearly established secondary centers, instead dissemination responds to local demands.
Analysis of new curriculum of class 11 biology/
The document analyzes and compares the new and old class 11 biology curriculum in Nepal. The new curriculum was revised based on research and suggestions to include more practical and application-based learning. It divides content into competencies, theory, and practical sections for both botany and zoology. While course content remained similar, the new curriculum reorganized some topics, increased practical hours, emphasized projects and field work, and implemented a blended assessment approach including internal and external evaluations. The goal of the revisions was to make the curriculum more conceptual, practical, and skill-based compared to the previous knowledge-based theoretical model.
Linkage/class 12 biology
linkage ppt slide is made for those learners which are a very weak understanding of the linkage concept. so it helps the students to take a clear concept from it.
Logical inference and inquiry
Logical inference and inquiry is a document about logic and logical reasoning. It discusses what logic is, including that it has two main parts - semantics and syntax. It also discusses logical inference as deriving conclusions from premises, and provides an example inference about dogs having four legs. The document outlines different rules of inference and their validity being based on form rather than truth. Finally, it discusses logical inquiry as any process aimed at increasing knowledge or solving problems, involving abductive, deductive and inductive reasoning.
Pteridophyta/ class 11 biology
This document describes the life cycle of ferns. It explains that ferns reproduce asexually through spores and sexually through gametophytes. The spores grow into heart-shaped prothalli that produce male antheridia and female archegonia for fertilization. Fertilization results in a diploid zygote that develops into a new fern sporophyte, completing the alternation of generations.
Epistasis/class 12 biology
it is about the genetic interaction, epistatic mechanism of dominant and recessive takes place in animal and plants
Environmental pollution/intermediate/campus level
this slide for biology students and helpful for intermediate and bachelor level students. students can learn about air pollution very easily. it gives a detailed description of air pollutants, their causes, and preventive measures with a clear photograph.
Chromosomal mutation/class 12 biology
this slide is about mutation especially on gene and chromosomal mutation for intermediate students. students can take benefit from it
Vegetative reproduction in angiosperm
Vegetative reproduction is a form of asexual reproduction in plants where new individuals are formed from vegetative organs like roots, stems, and leaves. There are two types of vegetative reproduction - natural, which occurs through modified roots, stems, and leaves; and artificial, where humans interfere to propagate plants through methods like layering, grafting, and tissue culture. Vegetative reproduction allows for the large scale, rapid production of identical new plants that inherit the parent's characteristics.
Animal behavior
- Animal behavior is the reaction and expression of organisms in response to external stimuli in their environment. This includes both innate, genetically determined behaviors as well as learned behaviors acquired through experience.
- Reflex actions are automatic, involuntary responses to stimuli that occur very quickly via neural pathways between receptors, the spinal cord, and effectors. An example is withdrawing one's hand from a hot object.
- The mechanism of a reflex involves stimulation of sensory receptors, conduction of impulses through sensory neurons to the spinal cord, modulation in the spinal cord, and transmission of impulses through motor neurons to effector organs to produce the reflex response.
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Equivariant neural networks and representation theory
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
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Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
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3:国家专业人才认证中心颁发入库证书
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Nucleic Acid-its structural and functional complexity.
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As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
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hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skillsANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptx
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Megasporogenesis/class 12 biology
- 2. • Formation of megaspores is termed as Megasporogenesis. • The female reproductive part of plant is called gynoecium. The unit of gynoecium is called pistil. Pistil bears stigma, style and ovary. Ovary bears ovule in the cavity of ovary called placenta. • Initially, ovule bears homogenous mass of cells called nucellus. • The nucellus is surrounded by two layer of integuments and attached with placenta by a short stalk called funiculus. • At early stage, one cell grows in size having dense cytoplasm which is known as primary archesporial cell. Later it divides mitotically into two cell, the megaspore mother cell and parietal cell • The megaspore mother cell increase in size and divides twice by meiotically to form four haploid megaspore.
- 4. • Out of four megaspores, three degenerates while one remains functional. • The functional megaspore grows rapidly by absorbing nutrition from nucellus, and forms embryo sac. The embryo sac consists one nucleus. • The nucleus of embryo sac further divides by mitosis into two cell. These nucleus move towards opposite poles. The pole of the embryo sac close to chalaza is called chalaza end and the one closer to micropyle is called micropylar end.
- 6. • Each daughter nuclei divides again, and results in four nuclei. Each nuclei divides again forming eight nuclei. • One nuclei from each end come to the center and fuse to form diploid secondary nucleus. • Three nuclei in the chalazal end called antipodal cells. Similarly the nuclei at the micropylar end form egg apparatus, consisting of two haploid synergids on either side of a large, central haploid egg cell.