问题 问答题 简答题

比较分析各植物遗传转化受体系统及其特点。

答案

参考答案:

组织器官受体系统:1.受体来源广泛,容易获得;2.适合于各种遗传转化方法,特别是农杆菌介导法;3.适应于各种能够通过组织培养获得再生植株的植物;4.获得再生植株的周期长

叶盘法、生殖细胞受体系统

中间繁殖体受体系统;特点:最理想的基因转化受体体统

1)获得再生植株周期短2)快速简单方便3)适合多种转化方法4)接受外源基因能力强转化率高

原生质体受体系统1)转化率高2)获得再生植株无性系变异多,转化的外源基因稳定性差

2)出现的嵌合体少4)技术难度大

生殖细胞受体:

A、利用单倍体遗传转化受体系统进行基因转化,避免了基因显隐性的影响,有利于基因的充分表达,通过染色体加倍后即可使基因纯合,缩短了目的基因纯合的时间,加快了转基因育种过程;

B、花粉管通道法和子房注射法由于操作简单,受实验室条件限制较小,已成为目前国内常用的转基因方法之一,同时,花粉管通道法是利用植物自身的有性生殖过程,有利于将现代的分子育种与常规育种紧密结合,也有利于目的基因在转基因后代中的稳定表达;

C、受体取材受到季节的影响大。利用花粉管通道法等进行遗传转化只能在短暂的开花期内进行,这是限制该系统应用的主要原因之一。

完形填空
Read the following text and choose the most suitable heading from A-F for each paragraph. There is one extra heading which you do not need.
A.Don’t overlook talented people around you
B.Seize the opportunity when it comes up
C.Stay humble
D.Find the system that works for your style
E. Keep Honest Forever
F.Work hard
小题1: __________
Lin(Jeremy Shu-How Lin)got to start for the Knicks because they had to start him. They had too many injuries. Baron Davis was gone. The other point guards were out. Carmelo Anthony was injured. Amare Stoudemire had to leave the team because of a family death. Lin could have squandered the opportunity and we would have never have noticed. But he made the most of it. You never know when opportunities are going to arise in life. Often, they’re when you least expect them. Make the most of them. Don’t waster them.
小题2: __________
Lin isn’t Michael Jordan or Kobe Bryant. He’s not a pure scorer. He’s a passer and distributor – who can also score very well. It didn’t work for him in Golden State or Houston – where he was before landing at the Knicks. But Mike D’Antoni’s system at the Knicks has been perfect for him to show off his strengths. You’ve got to do your best to understand what your strengths are and then ensure that you’re in a system (a job or organization or industry) that is a good fit for those strengths. Otherwise, people overlook the talents you bring to the table.
小题3: __________
You probably manage people at your own company today. Are you sure you don’t have a Jeremy Lin living among you now? How do you know that “Mike” couldn’t do amazing things if you gave him a new project to run with? How do you know “Sarah” isn’t the right person to take the open job in London that you’ve been talking over with your colleagues? We put people around us in boxes. He’s from Harvard. He’s Asian-American. Not sure he can play. How many assumptions have you made about talent around you? Don’t be like the General Managers in Golden State and Houston, and let talent slip through your fingers. With all their money, scouts(球探), and testing, they didn’t have a clue what they had in their hands. Do you know what your people (or even yourself)are really capable of? Take off the blinders of assumptions you wear when you look at the world.
小题4: __________
If you one day are lucky enough to have newspapers want to put you on the cover in order to sell more, don’t let it get to your head. It’s been remarkable watching how humble Lin remains through all this media craze. It makes his teammates and fans love him that much more.
小题5: __________
Lin couldn’t have seized his opportunity if he hadn’t worked like crazy for years perfecting his skills. There are no short cuts to hard work. Success is a by product of that. If you’ve got a Tiger Mom who’s always pushed you to work hard, great. If not, let your conscience be your own Tiger Mom! Get up early, stay up late. Nobody gave Lin any free passes. Why should you get any? You can only control what you control and that means you’ve got to work harder than anyone else you know.
填空题