题干

阅读理解

    You may be familiar with the following famous people, but have you heard of their graduation speeches, in which they either share their unforgotten experiences or give you some great inspiration(启迪).

    Michael Dell, University of Texas at Austin

    And now you've accomplished something great and important here, and it's time for you to move on to what's next. And you must not let anything prevent you from taking those first steps. ... You must also commit to the adventure. Just have faith in the skills and the knowledge you've been blessed (赐予)with and go.

    J.K. Rowling, Harvard University

    Half my lifetime ago ,I was striking an uneasy balance between my ambition and the expectation from my parents who were not rich...But what I feared most for myself at your age was not poverty(贫穷), but failure. The fact that you are graduating from Harvard suggests that you know little about failure, you might be driven by a fear of failure quite as much as a desire for success.

    Steve Jobs, Stanford University

    Sometimes life's going to hit you in the head with a brick. Don't lose faith...Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work, and the only way to do great work is to love what you do. If you haven't found it yet, keep looking, and don't settle.

    Bill Gates, Harvard University

    We need as many people as possible to have access to the advanced technology to lead to a revolution in what human beings can do for one another. They are making it possible not just for national governments, but for universities ,smaller organizations, and even individuals to see problems, see approaches and deal with the world's inequities(不公平)like hunger, poverty, and so on.

上一题 下一题 0.0难度 选择题 更新时间:2016-08-23 06:58:19

答案(点此获取答案解析)

同类题1

水稻淀粉合成代谢的遗传研究备受关注.相关研究的部分信息如图所示.请回答:

部分密码子表 络氨酸(UAC) 丝氨酸(AGC)

(1)AGPaes基因1如何使水稻表现出低产(淀粉含量低)的性状? ____ 

(2)用γ射线处理水稻进行诱变育种培育高产水稻品种.从图中可以看出,由于水稻AGPaes基因1中发生了碱基对的____ ,因而突变为AGPaes基因2而获得高产水稻突变体品种.在该突变基因中,若腺嘌呤与胸腺嘧啶之和占全部碱基数目的54%,其中一条单链中,鸟嘌呤与胸腺嘧啶分别占该链碱基总数的22%和28%,则由该链转录的RNA中,鸟嘌呤占碱基总数的____ %.

(3)比较研究后发现,基因突变部位编码的氨基酸分别为酪氨酸和丝氨酸,请写出基因中编码这两个氨基酸的碱基序列____ 

(4)研究表明,普通野生型水稻中拥有许多决定稻米优良品质的相关基因.

①育种工作者利用普通野生型水稻中存在的低比例直链淀粉突变体,以杂交育种方法培育出了优质栽培水稻品种.在杂交育种过程中,从F2代起,一般要进行多代自交和选择,自交的目的是____ .

②普通野生稻含有3.75×104对基因,假定每个基因的是10﹣5,那么在约有107个个体的种群中,每一代出现的基因突变数是____ ,它们是改良栽培稻的资源,也是进化的原材料.我国的普通野生稻分布于南方8个省(区),每一个分布点的普通野生稻种群都是生物进化的____ 

③据调查,我国不同地区的普通野生稻种群之间,含突变基因的杂合子的基因型频率存在着明显的差异.导致这种现象的原因有:____;(答够2个原因即可)