问题 选择题

人的皮肤肤色正常由显性基因A,白化病由隐性基因a控制,一对肤色正常的夫妇生了一个白化病孩子。则再生一个孩子患白化病的概率是多大

A.0

B.25%

C.50%

D.100%

答案

答案:B

题目分析:

白化病属于家族遗传性疾病,为常染色体隐性遗传,常发生于近亲结婚的人群中,生物的性状是由成对的基因控制的,成对的基因往往有显性和隐性之分。当细胞内控制某种性状的基因一个是显性、一个是隐性时,只有显性基因控制的性状才会表现出来,表现出显性性状时控制的基因有两种:两个显性或一个显性一个隐性,表现出隐性性状时控制的基因只有一种:两个都是隐性基因。一对肤色正常的夫妇生了一个白化病患儿,说明这对夫妇除含有一个控制正常肤色的基因外,都含有一个控制白化病的隐性基因,即夫妇双方的基因组成都是Aa,这对基因的遗传图解如图所示:

即白化病患者的基因组成是aa;若他们再生一个孩子,这个孩子患白化病的可能性25%。

单项选择题
阅读理解

How can you hear your friends’ voices when they are far away and you can’t make a long—distance call? Besides the web camera system with your computer, we have a new high-tech way to solve the problem and ease your pain of missing them.

The Japanese company Combiwith created a system—“talking picture”. It makes people in pictures speak!

The “talking picture” has a special pen. It is actually a pen-shaped scanner. It can scan information in special—made pictures. A connected player will then play the information out loud.

First, you need to take a picture and record what you want to say with the company. The company will then make special barcodes(条形码) onto your picture(you can’t see those codes). Those codes are your voice and your words. When you hold up the pen to scan your picture with barcodes, a player connected to the pen will start to play. It plays things you’ve recorded. That way the invention makes the “you” in the picture speak!

Do you want your friends and families talking out of pictures? Have them make pictures like that, and you can hear them whenever you want, only with the “talking picture” system. The system can play messages for up to 12 minutes.

“The pictures would be useful for those who hope to hear the voice of someone living far away,” said Mayumi Fuji, a spokeswoman for the company. “Grandparents, for example, longing to know about their grandchildren, would be happy to hear their voice when they see the picture,” Fuji said.

But it is troublesome to go to the company for taking a special picture first. And, it is much more expensive than using a telephone. The photo with barcodes costs between 17,040 and 17,990 yen(日元)(160 and 169 dollars). The larger picture you want, the more you pay.

Now, just raise a finger, lonely people can have their loved ones speak out of pictures. But, whether the “talking picture” is practical or not, let’s wait and see.

小题1:What does “talking pictures” mean according to this article?

A.The picture can play what’s been recorded as if the person in the picture “talks”.

B.You can have a talk with the person in the picture whenever you want to.

C.The picture can tell you wonderful stories to ease your pain.

D.The picture can tell what’s on your mind when you are looking at it.小题2:If you want to make a talking picture, you need to ________.

A.take a picture and record what you want to say with the company

B.make special barcodes onto your picture

C.a pen—shaped scanner to go with the picture

D.All of the above小题3:Which of the following is NOT true accordingly?

A.The talking picture system can play messages for 12 minutes at most.

B.It will cost you more to take a larger talking picture.

C.It might take a lot of trouble to make a talking picture.

D.You can make a talking picture by just raising a finger.小题4:What is the attitude of the author?

A.Optimistic.

B.Uncertain.

C.Positive.

D.Pessimistic.