英语翻译原文:Process of MeiosisUnlike the single-cell division of mitosis,meiosis involves two cellular divisions:meiosis I and meiosis II.Each stage of meiosis runs through the same five stages as discussed in mitosis.During the first round
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英语翻译原文:Process of MeiosisUnlike the single-cell division of mitosis,meiosis involves two cellular divisions:meiosis I and meiosis II.Each stage of meiosis runs through the same five stages as discussed in mitosis.During the first round
英语翻译
原文:
Process of Meiosis
Unlike the single-cell division of mitosis,meiosis involves two cellular divisions:meiosis I and meiosis II.Each stage of meiosis runs through the same five stages as discussed in mitosis.During the first round of division,two intermediate daughter cells are produced.By the end of the second round of meiotic division (meiosis II),the original diploid (2n) cell has become four haploid (n) daughter cells.
Meiosis I
Meiosis I is quite similar to mitosis.However,there are a number of crucial differences between meiosis I and mitosis,all of which will be outlined in the discussion of each individual stage below.
Interphase I
Just as in mitosis,the cell undergoes DNA replication during this intermediate phase.After replication,the cell has a total of 46 chromosomes,each made up of two sister chromatids joined by a centromere.
Prophase I
The major distinction between mitosis and meiosis occurs during this phase.In mitotic prophase,the double-stranded chromosomes line up individually along the spindle.But in meiotic prophase I,chromosomes line up along the spindle in homologous pairs.Then,in a process called synapsis,the homologous pairs actually join together and intertwine,forming a tetrad (two chromosomes of two chromatids each,or four total chromatids).Often this intertwining leads the chromatids of homologous chromosomes to actually exchange corresponding pieces of DNA,a process called crossing-over or genetic reassortment.Throughout prophase I,sister chromatids behave as a unit and are identical except for the region where crossover occurred.
Metaphase I
After prophase I,the meiotic cell enters metaphase I.During this phase,the nuclear membrane breaks down,allowing microtubules access to the chromosomes.Still joined at their crossover regions in tetrads,the homologous pairs of chromosomes,with one maternal and one paternal chromosome in each pair,align at the center of the cell via microtubules,as in mitotic metaphase.The pairs align in random order.
Anaphase I
Anaphase I differs slightly from its mitotic counterpart.In mitotic anaphase,sister chromatids split at their centromeres and are pulled apart toward opposite poles.In contrast,during anaphase I,the centromeres do not split:the entire maternal chromosome of a homologous pair is pulled to one end,and the paternal chromosome is pulled to the other end.
Telophase I
During telophase I,the chromosomes arrive at separate poles and decondense.Nuclear membranes re-form around them.The cell physically divides,as in mitotic cytokinesis.
一定要翻译啊 因为不光是要看明白 还要在课上翻译给老师听的
英语翻译原文:Process of MeiosisUnlike the single-cell division of mitosis,meiosis involves two cellular divisions:meiosis I and meiosis II.Each stage of meiosis runs through the same five stages as discussed in mitosis.During the first round
减数分裂的过程
不像有丝分裂只进行一次细胞分裂,减数分裂过程包括两次细胞分裂.减数第一次和减数第二次.每一次都会进行和有丝分裂一样的的五个阶段,在最初的阶段里,产生两个中间阶段的子细胞,在第二次分裂结束时,原始的二倍体细胞(2n)形成了四个单倍体(n)的子细胞.
减数第一次分裂
减一很像有丝分裂.但是,还是和有丝分裂有些很重要的区别.下面会针对每个阶段进行大概的介绍.
减一间期
就像有丝分裂,在间期会进行DNA的复制.在复制后,细胞的46条染色体的每条染色体上都有由着丝点相连的姐妹染色单体.
减一前期
有丝分裂和减数分裂的主要区别就发生在这个阶段.在有丝分裂前期,携带染色单体的染色体是在纺锤体中散乱分布的.但是在减一前期,这些染色体是成对在纺锤体中排列的.然后,在联会时,同源染色体因为太近而缠绕在一起,形成了四分体.(一共两条染色体,每条染色体上两个姐妹染色单体,总计四个单体).缠绕经常导致同源染色体内部的非姐妹染色单体会交换DNA的部分片段,这个过程叫交叉互换或者是基因重组.在减一前期,除了交叉互换的时候,姐妹染色单体是作为一个整体而且是相同的,除了交叉互换的片段.
减一中期
在减一前期之后,减数分裂的细胞就进入了减一中期.在这个阶段,核膜解体,允许纺锤丝连在染色体上.包括在四分体中交叉互换的片段,由一条母方的和一条父方的染色体构成的一对同源染色体,由于纺锤丝的作用,他们排布在细胞的中央,和有丝中期一样.这些成对的同源染色体也是随机排列的.
减一后期
减一后期和有丝后期有些微的差别.在有丝后期,姐妹染色单体由于着丝点的分裂而分开并且被拉向细胞的两极.相反,在减一后期,姐妹染色单体并不分离:同源染色体内的所有母方的染色体被分向一极,所有父方的染色体被分向另一极.
减一末期
在减一末期,染色体到达细胞的两极.核膜重建包围着染色体.细胞完全分开,就像在有丝分裂中细胞质分开一样.
减数分裂过程
不同的是有丝分裂的单细胞分裂,减数分裂细胞分裂包括两个:减数分裂I和减数分裂二。每个阶段的减数分裂同样的五个贯穿在有丝分裂的讨论阶段。在第一轮的分工,两个子细胞中间产生。到了减数分裂(减数分裂二),原二倍体(2n)的细胞都会变成四个单倍体(n)的子细胞第二轮结束。
减数分裂我
减数分裂我很相似,有丝分裂。然而,有一些重要的分歧之间减数分裂和有丝分裂的数目我,所...
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减数分裂过程
不同的是有丝分裂的单细胞分裂,减数分裂细胞分裂包括两个:减数分裂I和减数分裂二。每个阶段的减数分裂同样的五个贯穿在有丝分裂的讨论阶段。在第一轮的分工,两个子细胞中间产生。到了减数分裂(减数分裂二),原二倍体(2n)的细胞都会变成四个单倍体(n)的子细胞第二轮结束。
减数分裂我
减数分裂我很相似,有丝分裂。然而,有一些重要的分歧之间减数分裂和有丝分裂的数目我,所有这些将在下面的每个阶段的讨论概述。
相间余
正如在有丝分裂,细胞在这中间经历了DNA的复制阶段。复制后,细胞染色体有46辆,由两个姐妹染色单体由一个着丝粒加入。
前期我
之间的主要区别有丝分裂和减数分裂发生在这个阶段。在有丝分裂前期,双链个别染色体排队沿主轴。但是,在减数分裂前期我,染色体线沿主轴在同源对。然后,在这个过程被称为突触,相应的对实际联合起来,相互交织,形成了四分体(两个染色单体每两个或四个总染色单体染色体)。通常这种相互交织导致同源染色体的染色单体交换实际对应的DNA碎片,这个过程被称为过境转移或基因重组。在整个前期我,姐妹染色单体表现为一个单位,并为所在地区除交叉发生相同。
中期I
经过前期,我在此期间进入细胞减数分裂中期I阶段,核膜破裂,使微管进入染色体。在四分体仍然加入了他们的交叉区域,同源染色体配对,有一个母亲和一个父亲的每对染色体,对齐在细胞通过微管中心,在有丝分裂中期。在对随机顺序排列。
后期I
后期我略有不同的有丝分裂的对应。在有丝分裂后期,姐妹染色单体分离,并在他们的着丝粒被朝着相反的天壤之别。相反,在后期,我在着丝粒不要分裂:整个一对同源染色体上拉产妇的一端,而父系染色体拉向另一端。
末期我
在末期,我在不同的染色体到达极点和decondense。核膜重新周围形式。身体的细胞分裂,如在有丝分裂细胞分裂。
收起
减数分裂和有丝分裂的不同,看一下中文的就行了,翻译太麻烦了。