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(2018全国联赛,99)端粒酶(Telomerase)是细胞中负责端粒延长的一种酶,其活性在哺乳动物终末分化的体细胞中很低,在干细胞中则始终具活性。肿瘤中端粒酶被重新激活,可能参与恶性转化。科学家做了下列实验,研究小鼠中端粒酶的功能。科学家对 13.5 天小鼠胚胎成纤维细胞的核型和端粒长度进行检测。样品分别来自野生型小鼠和上述纯 合突变体(KO)小鼠间杂交产生的第二代(G2)、第 4 代(G4)和第 6 代(G6)。结果如下表,由此表可以知道:
A.
缺乏端粒酶活性的突变体小鼠，端粒逐代缩短
B.
随着繁殖代数的增加，残留的端粒酶被逐渐稀释，端粒越来越缩短
C.
端粒对维持染色体的稳定性必不可少，缺乏端粒造成染色体畸变
D.
端粒缩短使细胞分裂变慢，突变体胚胎生长速度逐代减慢
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【单选题】When Jackie says, "I don't think you're sorry at all--now. But you will be," she means ____________.
A.
she will try to do something to hurt Dean
B.
she wants Dean to apologize to her more sincerely
C.
she feels sympathy for Dean
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【简答题】根据化学方程式的书写步骤，写出下列过程中发生反应的方程式： （1）人在剧烈运动后，血液中会产生较多的乳酸（化学式为C 3 H 6 O 3 ），使肌肉酸痛．放松一段时间后，乳酸与吸入的氧气反应生成二氧化碳和水，使肌肉的酸痛感消失，该反应的方程式是：______． （2）为了适应火车提速，沪宁线上原有的短轨已全部连接为超长轨．工程技术人员常用铝和氧化铁（铁的化合价为+3）在高温条件反应生成氧化铝和铁来...
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【简答题】语法填空(二)Last October, while tending her garden in Mora, Sweden, Lena Pahlsson pulled out a handful of small 1____(carrot)and was about to throw them away. But something made her look closer, she notice...
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【判断题】热加工过程是增氢增碳的过程
A.
正确
B.
错误
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【单选题】历史唯物主义的基本观点是（）。
A.
社会存在决定社会意识
B.
社会意识决定社会存在
C.
物质文明和精神文明要两手抓
D.
社会意识是完全被动的
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【简答题】AC Milan star Kaka says a foot injury(受伤) is still stopping him from returning to football. He has not played for 32 days. Kaka says he is in a lot of pain. "I hurt myself in an area that we always pu...
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【单选题】由直线和圆弧组成的平面轮廓,编程时数值计算的主要任务是求各 ( )坐标。
A.
节点
B.
交点
C.
切点
D.
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【单选题】Protel 是专为( )设计开发的软件,其中不包括低压电器的元件库。
A.
电路仿真
B.
电力拖动设备电气原理图
C.
电子印制电路板
D.
检测电路
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相关题目：
【简答题】(二) Last October, while tending her garden in Mora, Sweden, Lena Pahlsson pulled out a handful of small 1____(carrot)and was about to throw them away. But something made her look closer, she noticed a...
查看完整题目与答案
【简答题】II. 单句改错 1. My uncle says that he never dreams of becoming rich in a short period of time. Instead, he hopes that our business will grow steadily. 2. Before her leaving, I prepared a gift to show my b...
查看完整题目与答案
【单选题】When Jackie says, "I don't think you're sorry at all--now. But you will be," she means ____________.
A.
she will try to do something to hurt Dean
B.
she wants Dean to apologize to her more sincerely
C.
she feels sympathy for Dean
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【简答题】根据化学方程式的书写步骤，写出下列过程中发生反应的方程式： （1）人在剧烈运动后，血液中会产生较多的乳酸（化学式为C 3 H 6 O 3 ），使肌肉酸痛．放松一段时间后，乳酸与吸入的氧气反应生成二氧化碳和水，使肌肉的酸痛感消失，该反应的方程式是：______． （2）为了适应火车提速，沪宁线上原有的短轨已全部连接为超长轨．工程技术人员常用铝和氧化铁（铁的化合价为+3）在高温条件反应生成氧化铝和铁来...
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【简答题】语法填空(二)Last October, while tending her garden in Mora, Sweden, Lena Pahlsson pulled out a handful of small 1____(carrot)and was about to throw them away. But something made her look closer, she notice...
查看完整题目与答案
【判断题】热加工过程是增氢增碳的过程
A.
正确
B.
错误
查看完整题目与答案
【单选题】历史唯物主义的基本观点是（）。
A.
社会存在决定社会意识
B.
社会意识决定社会存在
C.
物质文明和精神文明要两手抓
D.
社会意识是完全被动的
查看完整题目与答案
【简答题】AC Milan star Kaka says a foot injury(受伤) is still stopping him from returning to football. He has not played for 32 days. Kaka says he is in a lot of pain. "I hurt myself in an area that we always pu...
查看完整题目与答案
【单选题】由直线和圆弧组成的平面轮廓,编程时数值计算的主要任务是求各 ( )坐标。
A.
节点
B.
交点
C.
切点
D.
基点
查看完整题目与答案
【单选题】Protel 是专为( )设计开发的软件,其中不包括低压电器的元件库。
A.
电路仿真
B.
电力拖动设备电气原理图
C.
电子印制电路板
D.
检测电路
查看完整题目与答案
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