问题 实验题

植物生命活动调节的基本形式是激素调节,下面是有关植物激素的知识及实验研究,请根据有关信息分别回答下列问题:

(1)植物激素对植物的生长发育产生显著调节作用,植物的生长发育是由多种激素相互协调、共同调节的。下表是植物不同部位各种激素的相对浓度,请分析回答:

①.目前公认的植物激素共有五大类,除上表中的四大类外,植物体内还有一类物质也属于植物激素,该激素的主要作用是______________________________。

②.比较茎尖和伸长茎中各种激素的含量,从细胞角度分析植物的生长,说明生长素和赤霉素主要通过促进 ____,从而促进生长;细胞分裂素主要通过促进 _____,而促进生长。

(2)分析上表可知,成熟叶中含有较多的脱落酸而不含细胞分裂素。科学家通过进一步分析研究可知:脱落酸能抑制核酸、蛋白质的合成,促使叶片衰老。而细胞分裂素则抑制叶绿素、核酸和蛋白质的降解,抑制叶片衰老。所以在生产中可利用细胞分裂素作保鲜剂。请你设计一个实验证明细胞分裂素有延缓叶片衰老的作用。 

①.实验原理:叶绿素逐渐丧失而失去绿色是叶片衰老最明显的特点,离体叶片很快就会出现衰老的特点,因此,可通过________________________________来证明。 

②.实验步骤:

第一步:选取_______________叶片随机分成两组,分别标记为甲组、乙组。

第二步:_________________________。

第三步:___________________。

③.实验结果预测:________________。

④.实验结论:______________________。

答案

(1)①.促进果实的成熟      ②.细胞的伸长       细胞的分裂

(2)①.用细胞分裂素处理离体叶片,记录叶片失绿变黄所需的时间

②.第一步:同种植物、同样大小和发育状况相同的

第二步:在甲组叶片上涂一定浓度的细胞分裂素,在乙组叶片的相同位置涂等量的蒸馏水

第三步:记录甲、乙两组叶片失绿变黄所需的时间

③.甲组叶片失绿变黄所需的时间比乙组长

④.细胞分裂素有延缓叶片衰老的用

阅读理解

My name is Peter. I study in Cambell Middle School. It has a very large building. There are big playgrounds on two sides and a beautiful garden in front.

In the building, there is the headmaster’s room, the teacher’s rooms and thirty-four classrooms. We also have two labs(实验室) and a library in the building. Our library is on the ground floor. It has books almost (几乎)on all subjects. It opens after school from Monday to Friday.

Our school has uniforms(校服). Boys wear white shirts and blue trousers. Girls wear white blouses and blue skirts. We all wear black shoes and white socks.

We study English, Maths, History, Biology, Music and PE at school. My favourite subject is Biology. I think it is fun. Our teachers are nice to us. They check(检查) our homework and help us when we need. I love my school and my teachers.

小题1:How does the building look?

A.It’s very beautiful.

B.It’s very small.

C.It’s very large.

D.It’s very clean.小题2:Where is the garden?

A.The garden is in front of the building.

B.The garden is beside the building.

C.The garden is behind the building.

D.The garden is in the front of the building.小题3:How often does the library open?

A.The library opens two times a week.

B.The library opens three times a week.

C.The library opens four times a week.

D.The library opens five times a week.小题4:What does a girl wear at school?

A.A white shirt and blue trousers.

B.A white shirt and black trousers.

C.A white blouse and a blue skirt.

D.A white blouse and a black skirt.小题5:Which of the following is NOT true?

A.Peter studies six subjects at school.

B.Biology is Peter’s favourite subject.

C.There are lots of books in the library.

D.Their teachers are very fun.

单项选择题