题干

如图表示某真核细胞内三种具有双层膜的结构(部分示意图),有关分析错误的是( )

A:图a表示线粒体,H与氧结合形成水发生在有折叠的膜上

B:图b表示叶绿体,其具有自身的DNA和蛋白质合成体系

C:图c中的孔道是大分子进出该结构的通道,不具有选择性

D:图a、b、c中内外膜化学成分差异最大的是图a

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答案(点此获取答案解析)

C

同类题4

    I've loved my mother's desk since I was just tall enough to see above the top of it as mother sat doing letters. Standing by her chair, looking at the ink bottle, pens, and white paper, I decided that the act of writing must be the most wonderful thing in the world.
    Years later, during her final illness, mother kept different things for my sister and brother. “But the desk,” she'd said again, “it's for Elizabeth.”
    I never saw her angry, never saw her cry. I knew she loved me; she showed it in action. But as a young girl, I wanted heart-to-heart talks between mother and daughter
    They never happened. And a gulf opened between us. I was “too emotional(易动感情的)”. But she lived “on the surface”.
    As years passed I had my own family. I loved my mother and thanked her for our happy family. I wrote to her in careful words and asked her to let me know in any way she chose that she did forgive me.
    I posted the letter and waited for her answer. None came.
    My hope turned to disappointment, then little interest and, finally, peace—it seemed that nothing happened. I couldn't be sure that the letter had even got to mother. I only knew that I had written it, and I could stop trying to make her into someone she was not.
    Now the present of her desk told, as she'd never been able to, that she was pleased that writing was my chosen work. I cleaned the desk carefully and found some papers inside-- a photo of my father and a one-page letter, folded(折叠) and refolded many times.
    Give me an answer, my letter asks, in any way you choose. Mother, you always chose the act that speaks louder than words.