Egg - Ran

Japanese: 卵 - らん

Also called ovum or egg cell. The female gamete of organisms that reproduce sexually. It is larger than the male gamete, has no motility, and contains a large amount of nutrients in the cytoplasm. In animals, it is generally not as morphologically specialized as sperm, and is usually spherical or elliptical. It is larger than somatic cells (especially birds). It contains yolk as a nutrient, and based on the amount and distribution, it is classified into isoyolk eggs (echinoderms, mammals), in which the amount of yolk is relatively small and evenly distributed within the egg, terminal yolk eggs (molluscs, fish, amphibians, reptiles), in which the amount of yolk is relatively large and localized on one side of the egg, and cardiac yolk eggs (also called mesoyolk eggs; insects), in which the yolk is concentrated in the center of the egg. Eggs generally show polarity, with an animal pole (the part where the polar body emerges during egg formation; terminal yolk eggs have less yolk and more protoplasm) and a vegetal pole. Oogenesis takes place in the ovary. First, oogonia divide repeatedly to multiply. This then accumulates yolk and grows to become an oocyte, which then undergoes two further divisions, including meiosis, reducing the number of chromosomes by half to become an egg. In a broader sense, the term refers to the egg and its egg membrane, and can also refer to the embryo just before hatching from an unfertilized egg. In plants, it is formed inside the female gametangium. In angiosperms, the largest of the eight cells that make up the embryo sac is called an egg cell; in gymnosperms, the large cell in the archegonia is called an egg cell; and in ferns and mosses, the lower of the two cells in the archegonia is called an egg cell. In algae and fungi, it is formed inside the oophorum.
→Related items In vitro fertilization | Eggs | Cleavage | Ovipary

Egg [tamago]

In biology, it refers to an egg, or egg cell, but usually refers to the one that is laid outside the body. It contains the nutrient yolk in the cytoplasm and is surrounded by various tunicates. In bird eggs, the tunic is the egg white and calcareous shell, in insect eggs the thick ovarian membrane, and in frogs and newts the jelly-like substance is the tunic. The sea nightshade is also an egg sac of a marine snail. The size of the eggs varies from 68cm x 40cm in the whale shark, 16cm x 12cm in the ostrich, 33cm x 24cm in the Aepyornis (extinct), and 1.2cm x 0.8cm in a type of hummingbird. Among mammals, monotremes such as the platypus and echidna lay eggs. In general, the number of eggs laid tends to be greater when the parents leave the eggs alone, and less when the parents care for them. There are many types of fish, including 100,000 sardines and herrings, and 200 to 300 million sunfish.
→ Related topics (biology)

Egg [tamago]

Also written as tamago. Usually refers to chicken eggs. Highly nutritious, containing high-quality protein, the yolk in particular is rich in fat and vitamins A, _B1 , and _B2 . Depending on the breed of chicken, eggs can have white or red shells. They have a wide range of uses, including in dishes such as boiled eggs, fried eggs, tamagoyaki (rolled omelet, thick omelet, etc.), omelets, chawanmushi, and scrambled eggs, as well as being used as an ingredient in sweets such as castella and pudding.

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

卵子，卵細胞とも。有性生殖をする生物の雌性配偶子。雄性配偶子に比べて大きく，運動性をもたず，細胞質内に大量の栄養を含む。動物では一般に精子ほど形態的に特殊化せず，普通，球形か楕円形。体細胞に比べて大型（特に鳥類）。栄養分として卵黄を含み，その量や分布状態から，卵黄量が比較的少なく，卵内に均等に分布している等黄卵（棘皮(きょくひ)動物，哺乳(ほにゅう)類），卵黄量が比較的多く，卵の一方に局在する端黄卵（軟体動物，魚類，両生類，爬虫(はちゅう)類），卵黄が卵の中心部に集中する心黄卵（中黄卵とも。昆虫）などに区別される。また卵は一般に極性を示し，動物極（卵形成の際，極体が出た部位，端黄卵では卵黄が少なく，原形質の多いほう）と植物極とがある。卵形成は卵巣中で行われる。まず卵原細胞が分裂を繰り返して増殖。次いでこれが卵黄を蓄積して成長し卵母細胞になり，さらに減数分裂を含む２度の分裂を経て染色体数を半減し卵となる。なお広義には卵とその卵膜をあわせたものをさし，また未受精卵から孵化(ふか)直前の胚をさすこともある。植物の場合，雌性配偶子嚢内で作られる。被子植物では胚嚢(はいのう)を作る８細胞のうち，最大の細胞を，裸子植物では造卵器中の大きな１細胞，シダ，コケ類では造卵器内の２細胞のうち下方にあるものを，それぞれ卵細胞という。また，藻類や菌類では，生卵器の中に作られる。
→関連項目体外受精｜卵｜卵割｜卵生

卵【たまご】

生物学上は卵(らん)すなわち卵細胞をいうが，ふつうはそのうち体外に産み出されたものをいう。細胞質中に栄養物質である卵黄を含み，そのまわりはさまざまな被嚢物でおおわれる。被嚢物は，鳥卵では卵白と石灰質の殻，昆虫卵では厚い卵胞膜，カエルやイモリではゼリー状物質など。ウミホオズキも海産巻貝の卵嚢である。卵の大きさはジンベエザメで68cm×40cm，ダチョウで16cm×12cm，エピオルニス（絶滅）で33cm×24cm，ハチドリの一種では1.2cm×0.8cmなど。哺乳(ほにゅう)類でもカモノハシ，ハリモグラなどの単孔類は卵を産む。産卵数は一般に親が卵を産みっぱなしにするものほど多く，親が世話するものほど少なくなる傾向がある。魚類は多く，イワシやニシンで10万粒，マンボウでは２億〜３億粒といわれる。
→関連項目性（生物）

卵【たまご】

玉子とも書く。ふつう鶏卵をいう。栄養価が高く，良質のタンパク質を含み，特に卵黄は脂肪，ビタミンA，B₁，B₂に富む。ニワトリの品種により白殻と赤殻がある。ゆで卵（ボイルドエッグ），目玉焼（フライドエッグ），卵焼き（伊達巻，厚焼きなど），オムレツ，茶碗蒸し，いり卵（スクランブルドエッグ）などの料理に，またカステラ，プリンなどの菓子材料に使用されるなど用途が広い。

出典　株式会社平凡社百科事典マイペディアについて　情報

<<: Egg moss - Egg moss

>>: Lake Tama - Tamako