一、在做动植物细胞切片时,为什么总要先在载玻片上滴一滴清水或生理盐水? 做切片时滴一滴清水或生理盐水,可使所取样品中的细胞分散开来,便于镜检。制作动物细胞装片滴一滴和细胞液等渗的生理盐水,可使动物细胞维持原来的状态,既不皱缩也不破裂。而植物细胞外有细胞壁支持,吸水后不会胀裂,细胞的形态不发生变化,所以可滴一滴清水。二、观察唾液淀粉酶对淀粉的消化作用实验中,为何出现两次冷却? 制成的浆糊冷却后再加入唾液是防止唾液 First, when doing animal and plant cell biopsy, why should always first drop a drop of water or saline on the slide? Slides do a drop of water or saline, can take samples of the cells dispersed, easy to microscopic examination . Making animal cells packed with a drop of liquid and isotonic saline solution can make animal cells to maintain its original state, neither shrink nor rupture. The plant cells outside the cell wall support, will not crack after water absorption, cell morphology does not change, so you can drop a drop of water. Second, observe the salivary amylase digestion of starch in the experiment, why there are two cooling? Made paste cooling and then add saliva is to prevent saliva