题干

在自然界谷物中,水稻、玉米等都具有糯性,小麦没有糯性,品质主要由蛋白质含量和筋力来决定.由于缺少糯性性状,目前小麦面粉做成的面包、包子等食品保存时间长后容易发硬、开裂.江苏里下河农科所培育的糯小麦则解决了,这个难题.主要是通过江苏白小麦与日本关东l07、美国IKE等种间杂交后获得糯性基因,再用其后代与扬麦158进行多次回交,将糯性品质固定在扬麦l58品种上.

(1)上述材料中,江苏里下河农科所培育糯小麦的过程中运用的遗传学原理是____ .

(2)育种方法可以用图解表示为:

在短时间内获得糯小麦的育种方法是____ ,此方法从理论上获得yyRR的几率是____ .

(3)要获得yyRR,b过程需要进行____

(4)c过程中常用试剂是秋水仙素,其作用机理是____ .

(5)如果想提高突变率,你认为最好用哪种方法?____ .

(6)如果改用基因工程的方法,运载体可以用病毒,进入受体细胞的是病毒的____ ,其基本单位是____ .在免疫学上,进入人体内的病毒称为____ .

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    As a child, I started learning to play the piano, my favorite musical 1 but I was forced to give up when I started my middle school2 I could concentrate more on my studies.

    It's one of my biggest3 to stop practicing the piano when I recall sadly today. During the following years, I kept telling my piano teacher that I would4However, I didn't keep my promise because I was 5 with my study6 I lost touch with my teacher. Some years later, my teacher died. I was very sad because I lost such a good teacher. She was a very warm and gentle person. It hurts me to think she may have been 7 that I never returned. I haven't taken lessons since then but to be honest, I 8 to. Sitting at the piano, I couldn't help recalling many 9 ---times of my practising at home and playing before my teacher and one time my teacher 10 me after I played entire pieces of music wrong in front of her colleagues. I was so 11 that I could hardly say anything. But her 12helped ease my shame. These memories13good or bad, never caused my14 for playing the piano again.

    This thought then led me to think that 15 is like music, and that we all try to play different 16 in the instrument of our life. Sometimes the pitch (音高) is17when we play it well, but sometimes we are out of tone. However, we all continue to create our own 18style of music. No matter what style our music is, it is 19 that we sing the songs of joy, quietness and love. Though I may never make it back to piano lessons, it doesn't 20 that I've stopped making music.