问题 单项选择题

下列现象属于自由扩散的是()①水分子通过植物细胞的细胞膜②水分子通过植物细胞的细胞壁③蔗糖分子通过细胞壁④水分子或其他溶剂分子通过液泡膜⑤水分子或其他溶剂分子通过原生质层

A.①②③

B.③④⑤

C.①④⑤

D.①③⑤

答案

参考答案:C

解析:水分子和气体复制以及脂质小分子通过半透膜为自由扩散,故①正确。细胞壁为全透性,故②错。细胞壁全透性,大分子可以通过,不是自由扩散,故③错。水分子或其他溶剂分子通过液泡膜为自由扩散,故④正确。原生质层相当半透膜,故水分子或其他溶剂分子通过原生质层为自由扩散,故⑤正确。故C正确。考点:本题考查自由扩散相关知识,意在考查考生能理解所学知识的要点,把握知识间的内在联系能力。

选择题
完形填空
完形填空(共20小题;每小题l.5分,满分30分)
Once upon a time, there lived many doves (鸽子) in the jungle. One day they went out in search of food. They flew long distances   1  did not get anything to eat. All of them were now completely  2.
A young dove asked the King Dove, “Your Majesty(陛下), please   3  us to take some rest.” The king replied, “Have   4, my dear young fellow. We shall   5   get something to eat very soon.”
The young dove started flapping(拍打) his wings with   6  and soon left everyone else behind. After some time, he   7  and spoke to others, “Hey, I see lots of   8 down there.”
Hearing this, all the doves started  9  the scattered (散落的) grains under a banyan tree.   10  the King Dove said, “It is too good to be true. There is something wrong. Don’t rush towards the grains. It may be a   11 . Some hunter must have laid a trap(陷阱).”
But the doves were extremely hungry. The   12  of the grains was too tempting (诱惑人的). Without giving a(n)   13  to the king’s advice, they swooped (突然下降) down and started eating the grains. After having a big   14, they tried to fly away only to   15 that they were caught in a net.
The King Dove said, “I told you before that it is a trick of some hunter.”
All of them felt ashamed and   16  . One of them said to the King Dove, “Oh, Your Majesty, please save us.”
So the King Dove said, “All of you must try to fly with the   17  at the same time and in the same   18, all of you.”
Just then they saw a(n)   19  show up. The King Dove said, “Now all of you, fly together.”
So all the doves flapped their wings together and flew with the net. The hunter stood shocked. He couldn’t   20  what he had just seen.
小题1:
A.butB.andC.soD.however
小题2:
A.excited B.surprisedC.tiredD.embarrassed
小题3:
A.letB.leaveC.permitD.accept
小题4:
A.restB.courage C.luck D.belief
小题5:
A.slowly B.perhaps C.possiblyD.surely
小题6:
A.surpriseB.pleasureC.forceD.anger
小题7:
A.turned downB.turned back C.held backD.held down
小题8:
A.persons B.hunters C.plantsD.grains
小题9:
A.rushing towardsB.looking forC.picking upD.dropping down
小题10:
A.Gladly B.AmazedlyC.HardlyD.Suddenly
小题11:
A.magicB.trickC.dreamD.mistake
小题12:
A.colorB.smellC.viewD.sight
小题13:
A.soundB.thought C.ideaD.care
小题14:
A.meetingB.discussionC.mealD.break
小题15:
A.appreciate B.understandC.realizeD.concern
小题16:
A.pleasedB.scaredC.fullD.sick
小题17:
A.foodB.king C.netD.wing
小题18:
A.way B.placeC.circleD.direction
小题19:
A.hunter B.guideC.adultD.child
小题20:
A.believeB.rememberC.tellD.catch