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植物细胞的渗透吸水及原理,是高中生物教材中“水分代谢”的教学重点和难点之一。在45分钟的教学活动中,如能增加渗透现象的演示实验,并组织学生做好细胞质壁分离及复原的观察实验,将课堂教学改为以实验教学为主的形式,教学效果较好。实验及教学过程如下。一、渗透现象的演示实验演示实验的装置:撕取一块比较完整的洋葱鳞片的内表皮,用清水浸湿后,紧缚在古氏漏斗或者分液漏斗的口上。从漏斗的细玻璃管端注入0.8—1M蔗糖溶液,检查没有漏液现象后,把整个装置浸入盛有清水的容器内,使漏斗内
Plant cell infiltration of water and principles, is a high school biology textbook “moisture metabolism” teaching one of the key and difficult. In 45 minutes of teaching activities, such as demonstration experiments to increase the penetration phenomenon, and organize students to do cytoplasmic wall separation and recovery of observation experiments, the classroom teaching to experimental teaching as the main form, the teaching effect is better. Experiment and teaching process is as follows. First, the phenomenon of penetration demonstration Experimental demonstration device: Tear a relatively complete onion scales within the epidermis, wet with water, tightly tied in the ancient Funnel or separatory funnel mouth. Into the funnel from the fine glass tube 0.8-1M sucrose solution, check no leakage phenomenon, the entire device immersed in a container filled with water, the funnel