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

B

What happens inside the skull of a soccer player when repeatedly heads a soccer ball? That question motivated a challenging new study of the brains of experienced players that has caused discussion and debate among soccer players, and some anxiety among those of us with soccer-playing children.

For the study, researchers at the Albert Einstein College of Medicine in New York selected 34 adults, men and women. All of the volunteers had played soccer since childhood and now competed year-round in adult soccer leagues. Each filled out a detailed questionnaire developed especially for this study to determine how many times they had headed a soccer ball in the previous year, as well as whether they had experienced any known concussions (脑震荡) in the past.

Then the players completed computerized tests of their memory and other learning skills and had their brains scanned, using a complicated new M.R.I. technique which can find structural changes in the brain that can’t be seen during most scans.

According to the data they presented at Radiological Society of North America meeting last month, the researchers found that the players who had headed the ball more than about 1,100 times in the previous 12 months showed significant loss of white matter in parts of their brains involved with memory, attention and the processing of visual information, compared with players who had headed the ball fewer times.

This pattern of white matter loss is “similar to those seen in traumatic (外伤的) brain injury”, like that after a serious concussion, the researchers reported, even though only one of these players was reported to have ever experienced a concussion.

The players who had headed the ball about 1,100 times or more in the past year were also generally worse at recalling lists of words read to them, forgetting or fumbling the words far more often than players who had headed the ball less.

小题1:The passage is most probably a ________.

A.news report

B.research report

C.story for soccer players

D.text for doctors小题2: In which way can researchers find the structural changes in the brain?

A.Computerized test

B.Questionnaire

C.Scanning

D.M.R.I. technique小题3: From the passage we can conclude that frequent heading may have ________.

A.significant effect on brain

B.little effect on one’s brain

C.nothing to do with the brain injury

D.one’s memory improved小题4:What is likely to be the cause of memory loss?

A.Playing soccer frequently

B.Tests of their memory

C.White matter loss

D.Information processing小题5:The underlined word “fumbling” is closest in meaning to ________?

A.remembering

B.misunderstanding

C.recalling

D.missing

单项选择题