An ovum (plural ova) is a haploid female reproductive cell or gamete. "Haplo" redirects here For the fictional character see The Death Gate Cycle. Female (♀ is the Sex of an Organism, or a part of an organism which produces ova (egg cells A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete The word is derived from Latin, meaning egg or egg cell. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum. Both animals and embryophytes have ova. The embryophytes are the most familiar group of Plants They include Trees Flowers Ferns Mosses and various other green The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization. In Plants and Algae that undergo Alternation of generations, a gametophyte is the multicellular structure or phase that is Haploid, containing In lower plants and algae, the ovum is also often called oosphere. Non-vascular plants is a general term for those Plants (including the Green algae) without a vascular system ( Xylem and Phloem Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms
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Material contribution to offspring
The egg is the sole provider of such endosymbiotic organelles, including mitochondria within the cytoplasm. An endosymbiont is any Organism that lives within the body or cells of another organism i In Cell biology, an organelle (pronunciation /ɔː(rgəˡnɛl/ is a specialized subunit within a cell that has a specific function and is usually separately enclosed These cannot be produced with nuclear DNA alone and must be manufactured from DNA within existing organelles of their type (such as mitochondrial DNA) — this is important in Human mitochondrial genetics and can be used to trace maternal and paternal ancestry, especially as plants contain chloroplasts as well. Mitochondrial DNA ( mtDNA) is the DNA located in Organelles called mitochondria. Mitochondrial genetics is the study of the Genetics of the DNA contained in Mitochondria. An ancestor is a Parent or ( recursively) the parent of an ancestor (i Sperm mitochondria gets destroyed by the egg.
Ova production
In higher animals, ova are produced by female gonads (sexual glands) called ovaries and all of them are present at birth in mammals, and mature via oogenesis. The gonad is the organ that makes Gametes The gonads in males are the Testes and the gonads in Females are the Ovaries. "Ovaria" redirects here This is also a proposed section and a Synonym of Solanum. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Oogenesis or rarely oögenesis is the creation of an Ovum (egg cell
Human and mammal ova
In the viviparous animals (which include humans and all other placental mammals), the ovum is fertilized inside the female body, and the embryo then develops inside the uterus, receiving nutrition directly from the mother. A viviparous Animal is an animal employing vivipary: the embryo develops inside the body of the mother as opposed to outside in an egg ( Ovipary Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus See also Evolution of mammals Eutheria ("true beast" are a group of Mammals consisting of Placental mammals plus all extinct Mammals An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The uterus (from the Latin word for womb) is the major Female reproductive organ of most Mammals including Humans One end the
The ovum is the largest cell in the human body, typically visible to the naked eye without the aid of a microscope or other magnification device. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called A microscope ( Greek: ( micron) = small + ( skopein) = to look or see is an instrument for viewing objects that are The human ovum measures between 100 and 200 µm in diameter[1][2][3][4]. A micrometre ( American spelling: micrometer; symbol µm) is one millionth of a Metre, or equivalently one thousandth of a Millimetre
Protist and plant ova
In protists, fungi and many plants, such as bryophytes, ferns, and gymnosperms, ova are produced inside archegonia. Protists (ˈproʊtɨst are a diverse group of eukaryotic Microorganisms Historically protists were treated as the kingdom Protista but this A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Bryophytes are all Embryophytes ('land Plants) that are non-vascular: they have tissues and enclosed reproductive systems but they lack Vascular tissue A fern is any one of a group of about 20000 Species of Plants classified in the phylum or division Pteridophyta, also known as Filicophyta Gymnosperm (Gymnospermae are a group of Spermatophyte seed-bearing Plants with Ovules on the edge or blade of an open Sporophyll, which are An archegonium (pl archegonia) from the Ancient Greek ἀρχή ("beginning" and γόνος ("offspring" is a multicellular Since the archegonium is a haploid structure, egg cells are produced via mitosis. "Haplo" redirects here For the fictional character see The Death Gate Cycle. Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei The typical bryophyte archegonium consists of a long neck with a wider base containing the egg cell. Upon maturation, the neck opens to allow sperm cells to swim into the archegonium and fertilize the egg. The resulting zygote then gives rise to an embryo, which will grow out of the archegonium as a sporeling (young sporophyte). A sporeling is a young plant or fungus produced by a germinated Spore, similar to a Seedling derived from a germinated Seed. All land plants and some Algae, have life cycles in which a haploid Gametophyte generation alternates with a Diploid sporophyte, the generation of a
In the flowering plants, the female gametophyte, which usually gives rise to the archegonium, has been reduced to just eight cells referred to as the embryo sac inside the ovule. The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group In Plants and Algae that undergo Alternation of generations, a gametophyte is the multicellular structure or phase that is Haploid, containing Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells The gametophyte cell closest to the micropyle opening of the embryo sac develops into the egg cell. Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells Upon pollination, a pollen tube delivers sperm into the embryo sac and one sperm nucleus fuses with the egg nucleus. Pollination in angiosperms and Gymnosperms is the process that transfers pollen grains, which contain the male Gametes (sperm to where the female The term sperm is derived from the Greek word (σπέρμα sperma (meaning "seed" and refers to the male reproductive cells. The resulting zygote develops into an embryo inside the ovule. The ovule in turn develops into a seed and in many cases the plant ovary develops into a fruit to facilitate the dispersal of the seeds. A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored In the Flowering plants an ovary is a part of the female reproductive organ of the flower or Gynoecium. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. Biological dispersal refers to those processes by which a Species maintains ecosystem Upon germination, the embryo grows into a seedling. Germination is the process whereby growth emerges from a period of dormancy A seedling is a young plant Sporophyte developing out of a plant embryo from a Seed.
Ova development in oviparous animals
In the oviparous animals (all birds, most fishes, amphibians and reptiles) the ova develop protective layers and pass through the oviduct to the outside of the body. Oviparous animals are animals that lay eggs, with little or no other Embryonic development within the mother Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers Oviduct is also another name for Fallopian tube In Oviparous Animals (those that lay eggs, the passage from the ovaries They are fertilized by male sperm either inside the female body (as in birds), or outside (as in many fishes). For soil improvement see Fertilization (soil. The term sperm is derived from the Greek word (σπέρμα sperma (meaning "seed" and refers to the male reproductive cells. After fertilization, an embryo develops, nourished by nutrients contained in the egg. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular It then hatches from the egg, outside the mother's body. See egg (biology) for a discussion of eggs of oviparous animals. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum.
The egg cell's cytoplasm and mitochondria (and chloroplasts in plants) are the sole means of the egg being able to reproduce by mitosis and eventually form a blastocyst after fertilization. The cytoplasm is the contents of a cell that is enclosed within the Plasma membrane. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei The blastocyst is the structure formed in early Embryogenesis, after the formation of the Blastocoel, but before Implantation.
Ovoviviparity
There is an intermediate form, the ovoviviparous animals: the embryo develops within and is nourished by an egg as in the oviparous case, but then it hatches inside the mother's body shortly before birth, or just after the egg leaves the mother's body. Ovoviviparous Animals develop within eggs that remain within the mother's body up until they hatch or are about to hatch Some fish, reptiles and many invertebrates use this technique. An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate
See also
- Egg (biology)
- Fertilisation
- Insemination
- Menstrual cycle
- Ovulation
- Pollination
- Pregnancy
- Respiratory burst
- Sperm
- Zygote
- Male egg
External links
- The Ovarian Kaleidoscope Database description of 1800 genes involved in ovarian functions
References
- ^ The Ovum, Gray's Anatomy of the Human Body, Yahoo! Education
- ^ Ovum, Online Medical Dictionary, CancerWEB, Newcastle University
- ^ Oogenesis, Dr. Uzwiak, New Jersey State University
- ^ Definition of Ovum, Biology-Online.org