Section outline

  • General

    Collapse all Expand all

  • 游戏起源 - 高级

    lesson content

    What's the biggest cell on Earth?
    ::地球上最大的细胞是什么?

    The ostrich egg - unfertilized, of course. Yes, this egg, just like a human ovum , is just one . It is a gamete with a haploid number of , formed through . The egg shell membrane encloses the containing the genetic material and the cytoplasm .
    ::当然,这个蛋是没有受精的。是的,这个蛋,就像一个人类卵子一样,只是其中的一个。它是一个游戏,里面有通过它组成的一个杂交数。蛋壳膜包含着遗传物质和细胞图层。

    Gametogenesis
    ::游戏起源

    At the end of meiosis, haploid cells are produced. These cells need to further develop into mature gametes capable of , a process called gametogenesis ( Figure ). produce gametes directly through meiosis in organs called gonads . Gametogenesis differs between the sexes. In the male, the production of mature cells, or spermatogenesis , results in four haploid gametes, whereas, in the female, the production of a mature egg cell, oogenesis , results in just one mature gamete.
    ::这些细胞需要进一步发育成成熟的调子,能够 。这个过程叫做游戏起源(图 ) 。 在叫做gonad 的器官中,通过调子产生调子直接产生调子 。 性别之间的基因起源不同。在男性中,成熟细胞的产生或精子的产生导致四个调子,而在女性中,一个成熟的蛋细胞的产生(图 ) 导致一个成熟的调子。

    lesson content

    Analogies in the process of maturation of the ovum and the development of the spermatids. Four haploid spermatids form during meiosis from the primary spermatocyte, whereas only 1 mature ovum, or egg forms during meiosis from the primary oocyte. Three polar bodies may form during oogenesis. These polar bodies will not form mature gametes.
    ::卵巢的成熟过程和精子发育过程中的模拟。 初级精子细胞的4个细微的精子在进化过程中形成4个细微的精子,而在初级精子细胞的进化过程中仅形成1个成熟的卵子,或者在初级卵细胞的进化过程中形成蛋状。 3个极体在发芽过程中可能形成。 这些极体不会形成成熟的调子。

    From gametogonium (plural, gametogonia ), male and female gametes develop differently - males by spermatogenesis and females by oogenesis. A gametogonium is a germ cell that divides into gametocytes during gametogenesis. Male gametogonia are called spermatogonia , and female gametogonia are called oogonia . However, the following pattern is common for both oogonia and soermatogonia (chromosome numbers depict human chromosomes):
    ::从游戏形(多元、游戏形)开始,男性和女性的游戏形群发展不同 -- -- 通过精子产生而成的男性和通过出血产生而成的雌性。一个游戏形群是一个细菌细胞,在游戏产生时分裂成游戏形细胞。男性游戏形群被称为精子,而女性游戏形群则被称为Ooogonia。然而,以下模式在Oogonya和Soermatogonia中都很常见(染色体数显示人类染色体 ):

    cell type ploidy chromosomes process
    gametogonium diploid 46
    primary gametocyte diploid 46 meiosis 1
    secondary gametocyte haploid 23 meiosis 2
    gametid haploid 23
    gamete haploid 23

    Spermatogenesis
    ::子形起源

    During spermatogenesis, spermatogonia (singular, spermatogonium ) form primary spermatocytes by mitosis. These cells go through the first of meiosis to produce secondary spermatocytes . These are haploid cells. Secondary spermatocytes then quickly complete the meiotic division to become spermatids , which are also haploid cells. The four haploid cells produced from meiosis develop a flagellum tail and compact head piece to become mature sperm cells, capable of swimming and fertilizing an egg. The compact head, which has lost most of its cytoplasm, is key in the formation of a streamlined shape. The middle piece of the sperm, connecting the head to the tail, contains many , providing energy to the cell. The sperm cell essentially contributes only to the zygote .
    ::在精子产生期间,精子解剖(单子、精子解剖)形成主要的精子细胞。这些细胞通过第一种线性细胞,产生次子精子细胞。这些细胞是手动细胞。次子精子细胞随后迅速完成微子分解,成为精子解解剖,它们也是手动细胞。由梅氏生成的4个手动细胞形成一个尖细尾和紧凑头片,成为成熟的精子细胞,能够游泳和施肥卵。紧凑的头部已经失去大部分细胞的细胞图谱,是形成一个简化形状的关键。精子中间部分,将头与尾部连接起来,含有许多精子,为细胞提供能量。精子细胞基本上只对振动脉做出贡献。

    lesson content

    A human sperm is a tiny cell with a tail. A human egg is much larger. Both cells are mature haploid gametes that are capable of fertilization, shown in this photograph. Notice the sperm with a head piece, a flagella tail that propels the sperm, and a mid piece, which is mostly mitochondria, supplying ATP. Essentially, the head piece just contains the paternal genetic material.
    ::人类精子是带有尾巴的小细胞。 人类蛋要大得多。 两种细胞都是成熟的、 能够施肥的杂交调子, 这在照片中显示。 注意精子有头片、 推进精子的旗尾和中间部分, 主要是mitochondria, 提供ATP。 基本上, 头片含有父系遗传物质 。

    Oogenesis
    ::来源来源

    On the other hand, the egg provides the other half of the DNA, but also , building blocks for compounds such as and , and other necessary materials. The egg, being much larger than a sperm cell, contains almost all of the cytoplasm a developing embryo will have during its first few days of life. Therefore, oogenesis is a much more complicated process than spermatogenesis.
    ::另一方面,蛋提供了另外一半的DNA,但也提供了诸如和(......)等化合物和其他必要材料的构件。 蛋比精子细胞大得多,几乎包含了发育中的胚胎在其生命的最初几天里将拥有的所有细胞。 因此,卵的产生比精子产生要复杂得多。

    Oogenesis begins before birth and is not completed until after fertilization. Oogenesis begins when a diploid oogonia (singular, oogonium ), which are the immature eggs that form in the ovaries before birth, undergoes mitosis to form primary oocytes , also with the diploid number of chromosomes. It proceeds as a primary oocyte undergoes the first cell division of meiosis to form secondary oocytes with the haploid number of chromosomes. The one egg cell that results from meiosis I contains most of the cytoplasm, nutrients , and organelles. This unequal distribution of materials produces one large cell, and one cell with little more than DNA. This other cell, known as a polar body , eventually breaks down. A secondary oocyte then undergoes the second meiotic cell division to form a haploid ovum , only if it is fertilized by a sperm. Once again this unequal cell division will produce a large cell and a polar body. The large cell develops into the mature egg cell.
    ::生成开始于出生前, 并且直到受精之后才完成。 生成开始于一个小卵蛋( 单卵、 ), 即卵巢中产的不成熟的卵, 开始于出生前, 开始于形成小卵细胞的分裂, 形成一个大细胞, 以及一个小于DNA的细胞。 另一种细胞, 被称为极体, 最终会崩溃。 一个小细胞, 开始于第二个细胞细胞分解, 形成一个小卵巢, 只有当它受到精子的发酵。 这个不均匀的细胞分解将产生一个大细胞和一个极体。 大细胞会发展到成熟的蛋细胞中 。

    lesson content

    Maturation of the ovum. Notice only 1 mature ovum, or egg, forms during meiosis from the primary oocyte. Three polar bodies may form during oogenesis. These polar bodies will not form mature gametes. Conversely, four haploid spermatids form during meiosis from the primary spermatocyte.
    ::卵巢的成熟期。 注意在主卵细胞的沉积过程中只有1个成熟的卵, 或蛋。 3个极体可能形成在孵化期。 这些极体不会形成成熟的调子。 相反, 在主精子细胞的沉积期里, 4个偶然的精子结子形成 。

    More on these gametes and their maturation will be presented in the Anatomy and Physiology concepts.
    ::解剖学和生理学概念将更多地介绍这些组合及其成熟情况。

     

     

    Summary
    ::摘要

    • Meiosis is a step during spermatogenesis and oogenesis.
      ::诊断是精子产生和产生过程中的一个步骤。
    • Spermatogenesis produces four haploid sperm cells, while oogenesis produces one mature ovum.
      ::Spermato 产生产生 4 条状精子细胞, 而 ocreate 产生一个成熟的卵巢。

    Review
    ::回顾

    1. Define gametogenesis.
      ::定义游戏起源 。
    2. Discuss the role of meiosis in gametogenesis.
      ::讨论在游戏产生过程中的共融作用。
    3. Compare and contrast spermatogenesis and oogenesis.
      ::比较和对比 精子的产生和卵的产生。
    4. Define polar bodies.
      ::定义极地身体。