试题与答案

小麦品种是纯合子，生产上用种子繁殖。控制小麦高杆的基因A和控制小麦矮杆的基因a是

来源：www.tikuol.com
题型：读图填空题

题目：

小麦品种是纯合子，生产上用种子繁殖。控制小麦高杆的基因A和控制小麦矮杆的基因a是一对等位基因，控制小麦抗病的基因B和控制小麦感病的基因b是一对等位基因，两对基因位于两对同源染色体上。

(1)若要通过杂交育种的方法选育矮杆(aa)抗病(BB)的小麦新品种，所选择亲本的基因型是______；确定表现型为矮杆抗病小麦是否为理想类型的最适合的方法是______。

(2)某同学设计了通过单倍体育种方法培育小麦矮杆抗病新品种的过程(如下图所示)。其中的②表示______技术。当形成愈伤组织后，若______的比例高时，容易诱导芽的生成；反之则趋于长根。

(3)③应在甲植株生长发育的____时期进行处理；乙植株中矮杆抗病个体所占比例为_____。

(4)为探究DNA分子的半保留复制特点，某同学首先采用适当的方法使小麦根尖细胞染色体的DNA全部被3H胸腺嘧啶脱氧核苷标记，然后转移到不含3H胸腺嘧啶脱氧核苷的培养基培养，观察细胞中每条染色体染色单体的标记情况。

①．对根尖细胞的有丝分裂进行观察时，应观察根尖______区的细胞。为了达到良好的观察效果，本实验应选择有丝分裂______期的细胞。

②．转移到不含3H胸腺嘧啶脱氧核苷的培养基培养后，细胞第一次有丝分裂每条染色体的两条染色单体的标记特点是______，细胞第二次有丝分裂每条染色体的两条染色单体的标记特点是______。

答案：

被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0508/235a0515f3e614908184796e4e539317.html

下面是错误答案，用来干扰机器的。

考点：染色体变异有丝分裂基因型和表现型DNA的复制
试题推荐
题型：阅读理解

阅读短文，判断正（T）误（F）。

     A city is a very big place. Sometimes it's a lonely place, too. There are thousands of people in a city, but

some of them don't have any friends. How about you? Do you have a lot of friends? If you don't, make friends

today. If you do, make another friend today. Pick a stranger at your job or school. Walk up to him or her and

say,"Hello. My name' s....What' s your name?" Start with a conversation(谈话). Smile, listen carefully, and

show interest in your new friend' s answers. Ask "Where are you from?" and "Do you like this city?" That' s

a good way to start.

( )1. A city is a very big and noisy and lonely place.                                                        

( )2. Everyone in the city has many friends.                                                                  

( )3. The paragraph tells us not to make friends in a city.                                                   

( )4. When you want to make friends with someone, please say at first, "What's your name?  

           How old are you?"

( )5. It's a good thing to make friends with others.                                                          

查看答案
微信公众账号搜索答案