题干

本题共三个小题.

Ⅰ如图甲装置,请回答下列关于光合作用的问题:

(1)测甲叶片光合作用时,除满足充足的光照,适宜的温度外,A液体的作用是____ .测得容器中气体变化量是____ 

(2)叶绿体中色素主要吸收可见光中的____ 光.

(3)如果供给植物H2O18,容器含O18的物质有____ 

Ⅱ如图乙示翻译过程,图丙是甲图方框内部分的放大.思考并回答下列问题:

(1)翻译过程中,肽链上的氨基酸由____  (填mRNA或tRNA)上的三个碱基组成的密码子决定.一种氨基酸可以由____ 种密码子决定.

(2)一种tRNA能携带____ 种氨基酸.图乙中不同的核糖体合成的肽链是否一定相同?____ 

Ⅲ下列是关于变异与育种的一些问题.请思考并回答:

(1)杂交育种过程中,从F2选出的符合需要的优良性状的组合类型,是否一定要经过连续自交获得纯合子才能在生产中推广?____ .如果需要,能大大缩短育种年限的方法是____ ,其原理是____ .

(2)转基因食品是否一定对人体健康有害?____ 

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同类题4

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Unchangeable Love

    One day I visited an art museum while waiting for my husband to finish a business meeting. I was expecting a quiet 1 of the splendid artwork.

    A young 2 viewing the paintings ahead of me 3 nonstop between themselves. I watched them a moment and decided the lady was doing all the talking. I admired the man's 4 for putting up with her 5 stream of words. 6 by their noise, I moved on.

    I met them several times as I moved 7 the various rooms of art. Each time I heard her continuous flow of words, I moved away 8.

    I was standing at the counter of the museum gift shop making a 9 when the couple approached the 10. Before they left, the man 11 into his pocket and pulled out a white object. He 12 it into a long stick and then tapped his way into the 13 to get his wife's jacket.

     "He's a 14 man." the clerk at the counter said. "Most of us would give up if we were blinded at such a young age. During his recovery, he made a promise his life wouldn't change. So, as before, he and his wife come in 15 there is a new art show."

     "But what does he get out of the art?" I asked. "He can't see."

     "Can't see! You're 16. He sees a lot. More than you and I do," the clerk said. "His wife 17 each painting so he can see it in his head."

    I learned something about patience, 18 and love that day. I saw the patience of a young wife describing paintings to a person without 19 and the courage of a husband who would not 20 blindness to change his life. And I saw the love shared by two people as I watched this couple walk away, hand in hand.