基因经精子或卵细胞的传递（一）-学易试卷君之每日一题君下学期八年级生物人教版（课
题型：选择题※难度：一般
<div><div><p>【题目】如图是母方体细胞中的染色体及其携带的基因示意图，其产生的卵细胞示意图为下图中的（ ）</p><p><img src="https://picture.zhihuicn.com/2019/01/04/17/c00a2b72/SYS201901041713225225140383_ST/SYS201901041713225225140383_ST.001.png" width="91" height="87" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /></p><p>A. <img src="https://picture.zhihuicn.com/2019/01/04/17/c00a2b72/SYS201901041713225225140383_ST/SYS201901041713225225140383_ST.002.png" width="93" height="89" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /> B. <img src="https://picture.zhihuicn.com/2019/01/04/17/c00a2b72/SYS201901041713225225140383_ST/SYS201901041713225225140383_ST.003.png" width="93" height="89" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /> C. <img src="https://picture.zhihuicn.com/2019/01/04/17/c00a2b72/SYS201901041713225225140383_ST/SYS201901041713225225140383_ST.004.png" width="90" height="88" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /> D. <img src="https://picture.zhihuicn.com/2019/01/04/17/c00a2b72/SYS201901041713225225140383_ST/SYS201901041713225225140383_ST.001.png" width="91" height="87" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /></p></div></div>
<div><p>【答案】A</p><p>【解析】体细胞中染色体是成对存在，在形成精子和卵细胞的细胞分裂过程中，染色体都要减少一半。而且不是任意的一半，是每对染色体中各有一条进入精子和卵细胞。因此，如图是母方体细胞中的染色体及其携带的基因示意图，两对染色体、基因都要分开，因此其产生的卵细胞示意图为A。</p></div>
题型：选择题
※难度：一般
<div><div><p>【题目】如果亲代的体细胞染色体为2n，那么从亲代到生殖细胞再到子代，染色体数量的传递规律是</p><p>A. 2n、2n、2n</p><p>B. n、n、n</p><p>C. n、2n、n</p><p>D. 2n、n、2n</p></div></div>
<div><p>【答案】D</p><p>【解析】亲代在产生生殖细胞的过程中，成对的染色体要分开，分别进入两个生殖细胞中，因此生殖细胞中的染色体数目比体细胞减少一半；受精卵中的染色体来自于精子和卵细胞，数目又恢复到亲代体细胞中的染色体数。如图所示：<img src="https://picture.zhihuicn.com/2019/01/04/17/17fa67eb/SYS201901041723235431438677_DA/SYS201901041723235431438677_DA.001.png" width="371" height="199" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /><br />因此从亲代的体细胞到生殖细胞再到发育成子代的受精卵，细胞中的染色体的数量变化是2n→n→2n。</p></div>
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