题目

Breaking Bad Eating -HabitsHave you heard the expression You are what you eat? Well, do you like who you are'' If not, break some bad eating habits and feel better about yourself. Bad habit 1: ______________ Many packaged ( = in small bags) foods, such as frozen （纤维) dumplings ,rice rolls and instant noodles (方便面) have lots of fat and calories (热量). The solution: Read the instructions to find the healthiest foods that are low in salt and nigh in fiber Also check to make sure they have ingredients such as vegetables and grains When possible, use packaged foods as part of a home-图1为研究渗透作用的实验装置示意图，图2表示紫色洋葱解片叶外表皮细胞处在某浓度的外界溶液中的一种状态（此时细胞有活性），图3是选用蔗糖作为实验材料，用U型管所做的渗透实验，请回答下列问题： （1）图1中的渗透作用发生需要两个条件：①有半透膜，②_________________________。当液面上升到最大高度后处于静止状态时，____________（选填“有”或“无”）水分子通过半透膜进入漏斗中。（2）在做观察植物细胞的质壁分离和复原的实验过程中，常选用图2所示的紫色洋葱鳞片叶外表皮细胞作为实验材料，原因是该种细胞具有__________________，在进行实验时需要用显微镜观察_________次，细胞处于该状态时，A，B处的浓度关系为_________________________。（3）图3实验结果说明蔗糖分子不能通过半透膜，某同学想继续探究蔗糖水解产物能否通过半透膜，他向b管中滴加了两滴一定浓度的蔗糖酶，并在适宜温度下水浴保温一段时间，观察实验现象并预测实验结果：①一段时间后，若发现a，b两管的液面高度差继续增大，直至最后稳定不变。请分析造成此现象的原因有：______________________；____________________________。②一段时间后，若发现b管液面先上升后下降，直至b侧液面仅略高于a侧后不再变化。为使两侧液面等高，应进行的操作是_________________________________。