题干

细菌和真菌与人的生活息息相关.有时候同学们在教室里上课或者在操场里活动都可能感染病菌而发病,教师和操场哪里的细菌和真菌更多?阴雨连绵的季节,保存不当的食品和衣物表面很容易发霉,这是空气中的霉菌孢子在食品和食物表面大量繁殖导致的.霉菌的生活受哪些非生物因素的影响呢?下面是某探究小组的同学针对以上问题做的两个探究实验,请帮助该小组完成探究实验并分析回答相关问题.

实验一:为了探究教室和操场中细菌和真菌的分布情况,该小组同学做了下列探究实验:

【提出问题】教室和操场哪里的细菌和真菌更多?

【材料用具】每组三套装有牛肉汁培养基的培养皿(已高温灭菌)、标签纸、放大镜、透明胶带、恒温培养箱等

【实验步骤】

①在标签纸上标出组别、实验日期、编号(1号,2号,3号),将标签贴在培养皿底部.

②采集细菌和真菌:在教室、操场同时打开两只培养皿,暴露在空气中10分钟,再盖上、封好;一只培养皿不打开.

③将三只培养皿同时放入恒温箱中培养48分钟.

④观察、记录.

【实验现象】如图1所示:

实验二:为了探究霉菌的生活受哪些非生物因素的影响,该小组同学做了下列探究实验:

组别

A

B

C

处理方法

将100克烤干的馒头片置于塑料袋中,扎紧袋口,放在温暖环境里

将100克湿润的馒头片置于塑料袋中,扎紧袋口,放在温暖环境里

_________置于塑料袋中,扎紧袋口,放在_________环境里

实验结果(一周后观察)

不发霉

发霉

不发霉

【实验现象】发霉的馒头块情况如图2所示:

回答下列问题:

上一题 下一题 0.0难度 选择题 更新时间:2019-06-24 09:21:20

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同类题3

阅读下列短文, 根据短文中的信息完成文后表格, 每空一词。

      WARNING(警告): Holding a cell phone against your ear or putting it in your pocket may be bad for your health. This sentence is a warning that you’d better not put it close to you when a new phone is bought. Apple company, for example, doesn't want iPhones to come closer to you than 1.5 centimeters; Research In Motion, BlackBerry's producer, recommends 2.5 centimeters.

      If cell phone use can cause health problems, the result will be very serious. Americans spend 2.26 trillion minutes chatting on cell phones every year, which brings $109 billion for the wireless businessmen.

      Devra Davis, an epidemiologist(皮肤病专家)who has worked for the University of Pittsburgh, has published a book about mobile phone radiation(辐射)"Disconnect." Davis studies how often brain cancer happens during different age groups. As a result of mobile phone radiation, she finds that a big increase(增长)in brain cancer in the 20-to-29 age group and a drop for the older people.

      Children are more easily hurt by radiation than grown-ups, Ms. Davis and other scientists point out. But no studies have yet been finished on cell phone radiation and children, she says.

      Henry Lai, a research professor, began lab radiation studies in 1980 and found that mice exposed to(暴露在) radiofrequency(电波频率)radiation had destroyed DNA in their brains.

      Ms. Davis recommends using wired earphones(有线耳机)or the phone's speaker. Children should send text messages rather than call, she said, and pregnant women should keep phones away from their bodies.

It's ____to your health to use cell phones

____from different companies.

● Apple company ____ using cell phones at least 1.5 centimeters.

● Motion, BlackBerry's producer ____ 2.5 centimeters.

The____of research from different areas

● Devra Davis pointed out in the book "Disconnect" that people in the 20-to-29 age are more likely to have brain cancer than older people ____of mobile phone radiation.

● Ms. Davis and other scientists studied that Children are ____ to be hurt by radiation than adults.

● Henry Lai found that ____exposed to(暴露在) radiofrequency(电波频率) radiation had destroyed DNA in their brains.

Ms Davis's____on how to use the cell phone safely

●Children should send text messages ____of call.

 Pregnant women should keep phones away from their bodies.