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题型:实验探究题 题类:真题 难易度:普通

重庆江津区2019年九年级初中毕业学业考试生物试卷

维生素C能使紫色的高锰酸钾溶液褪色。某生物实验小组的同学为了探究不同蔬菜中维生素C的含量,把黄瓜、芹菜、菠菜用榨汁机榨出汁液后,分别装入三支烧杯中备用。请根据有关知识回答下的问题:
(1)、在榨出的三种蔬菜榨出汁液里,维生素C溶解在细胞的哪一结构中?。人体严重缺乏维生素C时会患
(2)、同学们在三支干净的试管里,加入相同浓度的高锰酸钾溶液,对应编成1、2、3号,接着用一支滴管吸取黄瓜榨出汁滴入1号试管中,记录下高锰酸钾溶液褪色的滴数是12滴,然后再用这支滴管分别吸取芹菜榨出汁液和菠菜榨出汁液滴入2号和3号试管中直至褪色,记录所用的滴数分别是16滴和8滴。

根据实验数据,该组同学得出的结论是菠菜的维生素C含量最高。你认同这个结论吗?

(3)、如果不认同,你认为应该改进的地方是:①,②
举一反三
选取三枝同一植物的长势相同的枝条分别标记为A、B、C, 作如下表的处理后,分别插入相同大小的、盛有等量蒸馏水的量筒中,并以石蜡油覆盖密封水面,置于适宜环境条件下。2小时后观察记录各组量筒中蒸馏水的减少量(说明:涂抹凡士林能堵塞叶片相应部位气体进出的通道)。请回答下列问题:                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

枝条编号

枝条处理

蒸馏水减少量

A

不作任何处理

2mL

B

凡士林涂抹所有叶片下表面

0.5 mL

C

除去枝条上的所有叶片

0 mL

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