问题 问答题 简答题

何谓transposon、R质粒、Hfr菌?

答案

参考答案:

转化(transformation):受体菌直接摄取供体菌游离的DNA片段获得新的遗传性状的过程称为转化。

R质粒(耐药传递因子):编码性菌毛、r决定因子:耐药

Hfr(高频重组菌株):F质粒与染色体整合。具有结合和转移功能、细菌染色体转移频率高,F质粒低、受体菌获得供体菌性状、用于绘制基因图

阅读理解

阅读理解。

     The very wealthy English Baron Fitzgerald had only one child, a son, who understandably was the apple

of his eye. His wife died when the child was in his early teens. So Fitzgerald devoted himself to fathering the

kid. Unfortunately the son died in his late teens.

     Meanwhile, Fitzgerald's wealth greatly increased. He spent a lot on art works of the masters. Later

Fitzgerald himself became seriously ill. Before his death, he had carefully prepared his will as to how his

wealth would be settled-to sell his entire collection at an auction (拍卖).

     Because of the large quantity and high quality of his collection, a huge crowd of possible buyers gathered

for the auction. Many of them were museum directors and private collectors eager to bid (出价). Before the

auction, the art works were shown, among which was a painting of Fitzgerald's son by an unknown artist.

Because of its poor quality, it received little attention.

     When it was time for the auction, the auctioneer gaveled (敲槌) the crowd to attention. First the lawyer

read from Fitzgerald's will that the first art work to be auctioned was the painting of his son.

     The poor-quality painting didn't receive any bidders...except one-the old servant who had served the son

and loved him, and who for emotional reasons offered the only bid.

     As soon as the servant bought the painting for less than one English pound, the auctioneer stopped the

bidding and asked the lawyer to read again from the will. The crowd became quiet, and the lawyer read from

the will: "Whoever buys the painting of my son gets all my collection." Then the auction was over.

1. The English Baron Fitzgerald was ______.

A. a museum director

B. a master of art

C. an art collector

D. an art dealer

2. Why did the old servant bid for the painting of Fitzgerald's son?

A. He was devoted to the family.

B. He saw that no one bid for it.

C. He knew the content of the will.

D. He found it cheap for him to buy.

3. Fitzgerald's will showed _______.

A. his desire to fool the bidders

B. his invaluable love for his son

C. his sadness at the death of his son

D. his regret of having no children to take over his wealth

判断题