问题 单项选择题

赖氨酸的分子式为C6H14N2O2,谷氨酸的R基为C3H5O4,1分子赖氨酸和1分子谷氨酸形成的二肽化合物中C、H、O、N原子数依次是()

A.11、23、6、3

B.9、19、4、3

C.11、21、5、3

D.9、17、3、3

答案

参考答案:C

解析:

由氨基酸的结构通式可以推知谷氨酸的分子式为C3H5O4,,则一分子赖氨酸和一分子谷氨酸生成二肽的同时失去一分子水(H2O),故C元素个数为5+6=11,H元素个数为14+9-2=21,O元素个数为4+2-1=5,N元素个数为1+2=3,故C正确。

考点:本题考查氨基酸的结构通式,意在考查考生理解所学知识的要点,把握知识间的内在联系的能力。

阅读理解

Most summer camps for teens center around sports, or music and arts, or just for having fun. But some girls in the Washington suburb of Arlington County, Virginia, went to camp to get a taste of what its like to be a firefighter.

This is not a typical summer camp. But Michelle Pawlaw is glad she signed up for it."Getting to experience the fires hands-on is really cool and something that most people don't get to do," she said.

Michelle and eight other teenage girls are participating in the three-day camp offered by the Arlington County Fire Department located just outside of Washington.

“The purpose is to try to get young women interested in considering the fire service as a career” said firefighter Clare Burley, who is in charge of the program.

The free of charge, overnight camp is designed to let the girls experience what firefighters do in the line of duty to protect the community.

They take classes and learn how to climb the ladder on a fire truck, operate emergency tools and rescue on injured person. They also do their share of cleaning the firehouse and the equipment Firefighting is still a male-dominated (男性主导) service. Clare joined the department seven years ago, saying "We do everything that the guys do to the same standarD.We are tested to the same standarD.We are expected to operate at the same standard."

Most of the girls say they had never thought about becoming a firefighter, but the camp was a great learning experience.

"I think it is definitely not a job that only men can do. Women can do it just as well as men can," said Michelle Pawlaw.

'I think I can help other people if they need help and know what to do in case I am at a fire myself," said Kayla Ehrlich.

"I think it's fantastic; I could consider taking it as a career some day." said Monica Bartorsh.

And, the girls say, by spending three days together, they also made new friends and had a lot of fun.

小题1:____might become a firefighter in the future.

A.Monica

B.Kayla

C.Michelle

D.Clare小题2:What can be inferred from the text?

A.The camp offers classes on curing the injured

B.Teenage girls will become volunteer firefighters

C.Women can perform as well as men in firefighting

D.Firefighting will soon be a female-dominated service小题3:What do we know about Clare Burley from the passage?

A.She has served the department for 7 years

B.She doesn't like her career as a firefighter

C.She is the designer of the camp program

D.She does better in firefighting than men小题4:The purpose of the text is____.

A.to attract more campers

B.to introduce a new type of camp

C.to praise women firefighters

D.to gain support from government