问题 单项选择题

将紫色洋葱表皮细胞放在0.3g/mL的蔗糖溶液中,显微镜下不可能观察到的现象是()

A.液泡缩小

B.细胞壁与原生质层分离

C.液泡颜色变浅

D.细胞核位于原生质层内

答案

参考答案:C

解析:与0.3g/mL的蔗糖溶液相比,紫色洋葱表皮细胞液属于低渗溶液,所以将紫色洋葱表皮细胞放在0.3g/mL的蔗糖溶液中发生质壁分离,液泡缩小,颜色加深,细胞壁与原生质层分离。原生质层是指细胞膜、液泡膜以及二者之间的细胞质,细胞核位于原生质层。考点:考查质壁分离的知识。

阅读理解

Reading is an activity people enjoy a lot in their free time. Some like reading newspapers, and others enjoy novels or comic books. I like reading about the lives of great poeple. This always gives me a lot of ideas on how to make my own life better.

Great people are remembered not because they were handsome or beautiful, but because they did not give up when their lives were difficult. They used every opportunity to change their lives and make the world better.

One good example is Orville and Wilbur Wright, the two brothers who invented the airplane. The plane has made the world into a small village. Hard work, not good luck, is the reason why the Wright Brothers could invent this convenient machine and become remarkable people. Today we wtil remember them when we see planes in the sky.

When I feel sad, stories of great people always help me feel better. This is why I enjoy reading about great people’s lives.

小题1:What does“This”mean in the first paragraph?

A.Being a great person.

B.Living in a special way.

C.Reading about the lives of great people.

D.Reading newspapers, novels, or comic books.小题2:Which book might the writer be most interested in?

A.How to Build a Strong Plane

B.Ten books That have Made Our World Better

C.Use Every Opportunity to Read in Your Free Time

D.Michael Jordan: The Man Who Changed Basketball History小题3:What does “remarkable”mean in the third paragraph?

A.Nice and polite.

B.Tall and handsome.

C.Special and famous.

D.Lucky and interesting.

判断题