问题 单项选择题

单纯的磷脂分子在水中可以形成双层脂分子的球形脂质体(如图),它载入药物后可以将药物送入靶细胞内部,下列关于脂质体的叙述正确的是()

A.在a处嵌入脂溶性药物,利用它的选择透性将药物送入细胞

B.在b处嵌入脂溶性药物,利用它的选择透性将药物送入细胞

C.在a处嵌入水溶性药物,利用它与细胞膜融合的特点将药物送入细胞

D.在b处嵌入水溶性药物,利用它与细胞膜融合的特点将药物送入细胞

答案

参考答案:C

解析:磷脂分子是由亲水头部和疏水尾部组成,所以在a处嵌入水溶性药物。细胞膜结构是由磷脂双分子层构成的支架,利用这个特点可以通过自由扩散的形式将药物送入细胞。考点:本题考查了磷脂分子的组成特点的知识。意在考查考生理论联系实际,综合运用所学知识解决自然界和社会生活中的一些生物学问题的能力。

阅读理解

It was a winter morning, just two weeks before Christmas 2005. While most people were warming up their cars, Trevor, my husband, had to get up early to ride his bike four kilometers away from home to work. On arrival, he parked his bike outside the back door as he usually does. After putting in 10 hours of labor, he returned to find his bike gone.

The bike was our only transport. Trevor used it to get to work, putting in 60-hour weeks to support his young family. I was so sad that someone would steal our bike that I wrote to the newspaper and told them our story. Shortly after that, several people in our area offered to help. One wonderful stranger even bought a bike, then called my husband to pick it up. Once again my husband had a way to get to and from his job. It really is an honor that a complete stranger would go out of their way for someone they have never met before.

People say that a smile can be passed from one person to another, but acts of kindness from strangers are even more so. This experience has had a spreading effect in our lives because it strengthened our faith in humanity as a whole. And it has influenced us to be more mindful of ways we, too, can share with others. No matter how big or how small, an act of kindness shows that someone cares. And the results can be everlasting.

小题1:Why was the bike so important to the couple? (Within 10 words)

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小题2:How did people get to know the couple’s problem? (Within 3 words)

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小题3:What do the couple learn from their experience? (Within 12 words)

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单项选择题