问题 解答题

右面是光合作用实验的示意图,据图回答下列有关问题.

(1)将天竺葵放到黑暗处一昼夜的目的是将植物叶片中的______等有机物耗尽.

(2)将叶片的一部分从上下两面遮盖起来,这种设计方法在实验中起______作用.

(3)叶片经过酒精处理后,向叶片滴加碘液,未被遮盖的部分变成了蓝色,说明了叶片的这一部分内有______形成.

(4)根据光合作用过程所需的条件、原料和产物,尝试完成下面的光合作用反应式.

水+______

叶绿体
 有机物(主要是淀粉)+______.

答案

(1)该实验的方法步骤:暗处理→部分遮光、光照→摘下叶片→酒精脱色→漂洗→滴加碘液→漂洗→观察颜色即②⑦③⑥⑤④⑤①.把盆栽的天竺葵放到黑暗处一昼夜,目的是为了让天竺葵在黑暗中把叶片中的淀粉全部转运和消耗,这样实验中用碘液检验的淀粉只可能是叶片在实验过程中制造的,而不能是叶片在实验前贮存

(2)将叶片的一部分从上下两面遮盖起来,这种设计方法在实验中起对照作用.

(3)析实验现象,叶片的未遮盖部分遇碘变蓝,说明这里产生了淀粉,叶片的遮盖部分遇碘没有变蓝,说明这部分没有淀粉产生,进而说明光合作用需要光,淀粉是光合作用的产物.

(4)绿色植物通过叶绿体,利用光能,把二氧化碳和水转化成储存能量的有机物,并且释放出氧气的过程,叫做光合作用,即光合作用的原料是二氧化碳和水,产物是有机物和氧气,条件是光,场所是叶绿体,用反应式表达如图:

答案为:(1)淀粉;

(2)对照;

(3)淀粉;

(4)二氧化碳;氧气.

阅读理解

阅读理解

     Margaret , married with two small children , has been working for the 1ast seven years as a night

c1eaner, cleaning offices in a bigbuilding.

    She trained as a nurse, but had to give it up when her elderchild became seriously ill. "I would have

liked to go back to it, butthe shifts(工作班次)are all wrong for me, as I have to be home toget the

children up and off to school."

    So she works as a cleaner instead,from 9 am till 6 am fivenights a week for just£90 before tax and

insilrance. "It's betterthan it was last year , but I still think that people who work ' unsocialhours' should

get a bit extra."

    The hours she's chosen to work mean that she sees plenty of thechildren,but very little of her husband.

However, she doesn't thinkfhat puts any pressure on their re1ationship.

    Her work isn't physically very hard, but it's not exactlypleasant, either."I do get angry with people who

leave their officeslike a place for raising pigs. If they realized people like me have todo it,perhaps they'd

be a bit more careful. "

    The fact that she's working all night doesn't worry Margaret atail.Unlike some dark buildings at night,

the building where sheworks is fully lit, and the women work in groups of three. "Since I'vegot to be here,

I try to enjoy myself-and I usually do,because of theother girls. We all have a good laugh, so the time

never drags."

     Another challenge Margaret has to face is the !reaction of otherpeople when she tells them what she

does for a living.They thinkyou're a cleaner because you don't know how to read and write, "said

Margarit. "I used to think what my parents would say if theyknew what I'd been doing, but I don't think

that way any more. I don't dislike the work though I can't say I'm mad about it."

1. Margaret quit her job as a nurse because__________

A. she wanted to earn more money to support her family

B. she had suffered a lot of mental pressure

C. she needed the right time to look after her children

D. she felt tired of taking care of patients

2. Margarel gets angry with people who work in the office because_________. 

A. they never clean their offices

B. they look down upon cleaners

C. they never do their work carefully

D. they always make a mess in their offices

3. When at work , Margaret feels__________ 

A. light-hearted because of her fellow workers

B. happy because the building is fully lit

C. tired because of the heavy workload

D. bored because time passes slowly

4. The underlined part in the last paragraph implies that Margaret's parents would__________.   

A. help care for her children

B. regret what they had said

C. show sympathy for her

D. feel disappointed in her

选择题