Then there is Meiosis for our gametes, because they (gametes) are different.

然后是配子减，因为它们（配子）是不同的。

The answer lies within the amazing process of meiosis.

答案就在惊人的减过程中。

The secondary oocyte stops in metaphase of meiosis 2, and waits for fertilization as the menstrual cycle transitions into the luteal phase.

次级卵泡会在第二次减中期停止，并且在卵泡期向黄体期转换的时候等待受精。

More base pairs and more exons mean that there are more chances for mistakes during meiosis, which is when the egg or sperm are being created.

更多的碱基对和外显子意味着减时有更多出错的可，导致生成X染色体上有错误编码序列的卵细胞或者精子。

Typically a gamete with 23 chromosomes, including one sex chromosome either X or Y, develops when parent germ cells undergo the process of meiosis.

正常的配子包含23条染色体，其中有一条X或Y性染色体，由亲代生殖细胞减产生。

Now, only if and when an egg fuses with a sperm does it actually complete meiosis II and officially become an ovum.

现在，只有当卵子与精子融合时，它才真正完成减 II 并正式成为卵子。

To do this, the primary oocytes have to complete meiosis 1, and in a person's lifetime only about 400 successfully do that.

要变成配子就必须要经历第一次减，而一个人的一生中大概只有400个初级卵母细胞可以做到。

The LH gets to work on the oocyte that's been dormant inside the follicle, and triggers it to finally start dividing again — getting it to complete meiosis I and move on to metaphase II.

LH 开始作用于卵泡内休眠的卵母细胞，并触发它最终再次开始——让它完成减 I 并进入中期 II。

Nondisjunction means the chromosomes don't split apart - so following meiosis, one resulting sex cell ends up with both chromosomes and the other gets none.

不离意味着染色体没有开，所以在减后形成的两个细胞中，一个拥有2条染色体，而另一个一条都没有。

There are two types of cell division: Mitosis and Meiosis.

细胞有两种类型：有丝和减。

In a secondary follicle, the primary oocyte is still in the prophase step of meiosis 1, but now the follicle has additional layers of granulosa cells, as well as theca cells.

次级卵泡中的初级卵母细胞还是停留在第一次减前期，而卵泡多了几层颗粒细胞，以及卵泡内膜细胞。

These structures are critical for the process of cell division in next step at meiosis 1.

这些结构对减 1 的下一步细胞过程至关重要。

Remember that the " egg" is still just a secondary oocyte here, and hasn't completed meiosis. As the sperm delivers its payload, it causes a flash of calcium ions from the oocyte's endoplasmic reticulum.

请记住，“卵子”在这里仍然只是一个次级卵母细胞，还没有完成减。当精子传递其有效载荷时，它会从卵母细胞的内质网中产生钙离子闪光。

The other option is the sister chromatids of the x chromosome don't separate in meiosis two in the female germ cell.

女性生殖细胞中，X染色体姐妹染色单体在第二次减时没有离。

Meiosis 2 Meiosis 2 is the second meiotic division and usually involves equational segregation, or separation of sister chromatids.

减 2减 2 是减的第二次，通常涉及相等的离，或姐妹染色单体的离。

The first stage lasts from infancy to puberty, and during this stage the primary oocyte remains stuck in the prophase step of meiosis 1.

第一阶段从婴儿期到青春期，初级卵母细胞还停留在第一次减的前期。

If failure also happens during meiosis in these germ cells as they give rise to gametes, other XXXXY, XXXY and XXYY genotypes that also lead to Klinefelter syndrome can result including the rare situation where there's an additional Y chromosome.

如果有丝和减均发生了不离，那么这类Klinefelter综合征患者的基因型就可是XXXXY，XXXY和XXYY等，包括了同时多出一条Y染色体的罕见情况。

The oocyte then quickly completes meiosis II, leaving two daughter cells: the large ovum and a puny second polar body.

然后卵母细胞迅速完成减 II，留下两个子细胞：大卵子和一个微小的第二极体。

Similar to mitosis, cells also pass through the Interphase, G1, S and G2 phase before they enter Meiosis.

与有丝相似，细胞在进入减之前也经历了间期、G1、S 和 G2 期。

This triggers the primary oocyte within the dominant follicle to finally complete meiosis 1, and turn into a secondary oocyte, which has 23 chromosomes.

这使得优势卵泡里的初级卵母细胞最终完成第一次减，变成了有23条染色体的次级卵母细胞。