问题 填空题

从某种真核细胞中提取出大量核糖体,放入含有下列几种有机物(其中的氮原子已被15N标记)的培养液里,假设培养液里含有核糖体完成其功能所需的一切物质和条件。请回答:

(1)实验中,核糖体所需要完成的功能就是把上述物质中的[    ](填号码)__________,通过__________方式合成多肽(蛋白质),可以用_______试剂检测。

(2)实验中所用的培养液相当于细胞内的__________。

(3)上述有机物(每种只取一个)合成的多肽至少含有________个羧基,合成的多肽可能有________种。

(4)实验中,检测到某一多肽含20个15N,则该多肽最多有________个肽键

答案

(1)[①④⑤]氨基酸   脱水缩合   双缩脲

(2)细胞质基质

(3)2   三

(4)19

阅读理解

A businessman walks into a bank in San Francisco and asks for the loan officer. He says he is going to Europe on business for two weeks and needs to borrow $5,000.The bank officer says  the bank will need some kind of security for such a loan. So the businessman hands over the keys to a Rolls Royce parked on the street in front of the bank. Everything checks out, and the bank agrees to accept the car as collateral for the loan. An employee drives the Rolls into the bank’s underground garage and parks it there.

Two weeks later, the businessman returns, and repays the $5,000 and the interest, which comes to $15.41.

The loan officer says, “We are very happy to have had your business, and this transaction has worked out very nicely, but we are a little puzzled. While you were away, we checked you out and found that you are a multimillionaire. What puzzles us is that why would you bother to borrow $5,000?”

Laughing, the businessman replies, “Where else in San Francisco can I park my car for two weeks for $15?”

小题1:The businessman walks into the bank with the true purpose of _________.

A.borrowing $5,000

B.meeting the loan officer

C.finding a place to park his car

D.showing how rich he is小题2:The loan officer is puzzled because _________.

A.he never thought he could meet a multimillionaire in his bank

B.he thinks the businessman is crazy to leave his car in the bank

C.he never thought the businessman could drive a Rolls Royce

D.he thinks $5,000 is so small a sum of money to the businessman小题3:The underlined word “collateral” in Paragraph 1 most probably means “_________”.

A.security

B.payment

C.reward

D.deal小题4:Which of the following words can best describe the businessman according to the story?

A.Honest.

B.Clever.

C.Rich.

D.Kind.

单项选择题 案例分析题