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一、以面粉为材料,验证种子脂肪的存在在初中植物学“种子的成份”这一节教学中,我们以面粉为材料,验证种子中含有脂肪。具体操作如下:将三角匙面粉,放入250毫升烧杯中,再加入5毫升丙酮,用玻璃棒调成稀糊状。略加沉淀后,用一张2.5×8平方厘米的滤纸插入烧杯上清液中。即刻可看到上清液在滤纸条上上升,5分钟后就可看到滤纸上液体上升的终点处有黄色痕迹出现,这是脂肪积累所致。滤纸在烧杯中插得时间越长、滤纸上积累的脂肪越多、黄色越深。
First, the use of flour as a material to verify the existence of seed fat In the teaching of “Seeds Ingredients” in the junior middle school botany, we use flour as a material to verify that the seeds contain fat. The specific operation is as follows: Put the triangle spoon of flour into a 250 ml beaker, add 5 ml of acetone, and make a thin paste with a glass rod. After a slight precipitation, insert a 2.5 x 8 cm2 filter paper into the beaker supernatant. Immediately, the supernatant was seen rising on the filter paper. After 5 minutes, yellow marks appeared at the end of the liquid rising on the filter paper, which was caused by fat accumulation. The longer the filter paper is inserted into the beaker, the more fat accumulates on the filter paper and the darker the yellow color.