囊性纤维化是一种严重的遗传性疾病，导致这一疾病发生的主要原因是编码CFTR蛋白的基因发生突变，如图表示CFTR蛋白在氯离子跨膜运输过程中的作用．

（1）图中所示为细胞膜的____模型，其中构成细胞膜的基本支架是____ ，氯离子跨膜运输的正常进行是由膜上____ 决定的．

（2）在正常细胞内，氯离子在CFTR蛋白的协助下通过____ 方式转运至细胞外，随着氯离子在细胞外浓度逐渐升高，水分子向膜外扩散的速度____ ，使覆盖于肺部细胞表面的黏液被稀释．

（3）有一种CFTR基因突变会导致肽链错误折叠，使蛋白质的____ 结构发生改变，从而影响CFTR蛋白的正常功能．

单词拼写：根据短文内容和所给中文提示，在空白处写出单词的正确形式。每空限填一词。

    Tu Youyou, 84, is the woman who uses sweet wormwood's (青蒿)  special power to help millions of lives. Now she is ____ (广泛地) well-known as the winner of the 2015 Nobel Prize in Physiology or Medicine. We Chinese people take ____ (骄傲) in her.

    When Tu began her____ (医疗的) research in the 1960s, things were hard. They had neither modern machines ____ (也不) lots of money. But those didn't  ____ (阻止) her at all. She ____ (失败) many times, but she never gave up. And she even used to test medicine ____（通过）eating them herself. Tu was always busy with her work so she ____ (很少) stayed with her family. You can't imagine ____ (多么) hard her job was! Finally, Tu found artemisinin (青蒿素) in 1971. During the next few years, she made an effort to improve the medicine.

    According to World Health Organization, about 200 million people were  ____ (挽救) with the help of artemisinin. “I feel happy when I see patients become healthy again.” she said.

现在园艺师们往往将李子、杏 等果树修整成主干突出，侧枝层次分明、呈螺旋状均匀着生在主干上的树形。“有空就有枝，有枝就有果”，是对该树形的最佳描述。由此我们可以想到该树形丰产的主要原因是（　　）