问题 解答题

某研究性学习小组为探究皮肤的作用,做了如下的模拟实验,实验步骤是:

①把3只塑料袋分别标上1、2、3、号.

②用水轻轻地将3个新鲜苹果洗干净,然后用纸巾仔细地擦干苹果,作如下外理:

苹果1苹果2苹果3
处理不做处理将牙签插进一个腐烂的苹果里,然后拔出,用牙签的尖端在苹果2表面滑动,不划破果皮,重复这些动作3次与苹果2相似,只是牙签的尖端一定要刺穿苹果3的表面
将3只苹果分别塞入1、2、3号塑料袋,封好后存放在温暖黑暗的地方.

③每天将苹果从存放的地方取出,观察,记录后放回原处.

请分析回答:

(1)在这项实验中,用______模拟人的皮肤,腐烂的苹果中含______等微生物,将其涂在苹果皮或苹果内,相当于微生物培养中的______这一步骤.

(2)如果实验结果只有苹果3腐烂,你得出的结论是:______.

(3)某同学不小心划破了手背皮肤,但他不以为然,未做任何处理,结果不久伤口周围双红双肿,出现了炎症.请分析该同学伤口发火的原因.______.

答案

该实验的变量是果皮的完整性,被划破果皮的苹果是实验组,果皮完整的苹果是对照组,说明果皮对果实内部有保护作用.即,皮肤是一道保护屏障.对照实验是指在研究一种条件对研究对象的影响时,所进行的除了这种条件不同之外,其他条件都相同的实验.其中这种不同的条件就是实验变量.这样实验结果的不同只能是由变量引起的.使实验结果具有说服力.(1)接种,就是把已有的菌种,用某种方式取少量的菌种,接到培养基上的过程.接种的目的有多种,如:扩大培养、筛选菌种、选育等.不过其他的目的一般都建立在扩大培养的基础上.如划线法、涂布法、倾注法、斜面接种法、液体培养基接种法、螺旋接种法等.用无菌棉棒擦取手心,手上的细菌被黏附在棉棒上,相当于取菌种,在培养基上轻轻涂抹,细菌的菌种就接到了培养基上,这相当于细菌和真菌培养方法中的接种.

(2)如果实验结果只有苹果3腐烂,你得出的结论是:皮肤具有保护作用

(3)如果伤口较表浅,伤口表面又不洁净的话就会为需氧菌生长提供条件,加上伤口表面渗出的淡黄色透明液体(血小板)等血液成分提供营养,容易造成细菌滋生.如伤口较深则主要是厌氧菌生长,如破伤风菌等.有细菌生长自然会造成发炎,因为细菌对身体来说是异物,会引起炎症反应,然后白细胞大量聚集参加炎症反应,进而引起化脓.

故答案为:

(1)果皮;细菌;接种

(2)皮肤具有保护作用

(3)缺少皮肤的保护,细菌感染

阅读理解

Last weekend, twenty thousand people gathered in the state of Georgia to watch students from twenty-eight countries compete with robots they built. More than ten thousand students and more than five hundred robots took part in the competition.

Almost one thousand and seven hundred high school teams entered a level of competition called LUNACY. The competitors came from eleven countries, including the United States. In January, the organization sent the same supplies for robots to each team. The teams had six weeks to build robots that could compete in the LUNACY game. The playing area had six robots, three on each team. Each robot had a trailer(拖车) connected to it. The robots had to pick up large balls and throw them into the trailers of opposing robots. The robots were moving on a surface where they could slide(滑行). A team from California won the competition.

A second competition involved building a robot that could travel on uneven(不平坦的) surfaces, move objects with unusual shapes and withstand(承受) physical stress.

Another competition was for younger students, aged nine to fourteen years old. Eighty-four teams from twenty-seven countries competed with robots made with LEGO products. They had to design, build and program robots to explore the Earth’s climates.

小题1:The competitors coming from _______countries entered a level of competition called LUNACY.

A.twenty-eight

B.twenty-seven

C.eighty-four

D.eleven小题2:_______sent the supplies for robots to each team.

A.Schools

B.Volunteers

C.The government

D.The organization小题3:Each team can have _______robots to compete in the LUNACY game.

A.two

B.three

C.six

D.eight小题4:The underlined word “involved” in this passage can be replaced by “_______”.

A.included

B.removed

C.corrected

D.invented小题5:Which statement is NOT true according to the passage?

A.In January, each team got the same supplies for robots.

B.A team from California won the LUNACY competition.

C.The writer introduces three kinds of competitions in this passage.

D.The students had to design or buy robots for the competition.

多项选择题