题干

癌细胞与正常细胞相比,与RNA和DNA合成相关的酶活性显著增强,相应的,核酸的分解速率明显降低.这对应的癌细胞所具有的特征是(  )

A:能够无限增殖

B:细胞彼此间的黏着性降低

C:细胞呈球形

D:细胞呼吸以无氧呼吸为主

上一题 下一题 0.0难度 选择题 更新时间:2016-02-26 03:27:14

答案(点此获取答案解析)

A

同类题5

阅读理解

    In 1943, when I was 4, my parents moved from Coeur d'Alene, Idaho, to Fairbanks, Alaska, where adventure was never very far away.

    We arrived in the summer, just in time to enjoy the midnight sun. All that sunlight was fantastic for Mum's vegetable garden. Working in the garden at midnight tended to throw her timing off, so she didn't care much about my bedtime.

    Dad was a Railway Express agent and Mum was his clerk. That left me in a mess. I usually managed to find some trouble to get into. Once I had a little fire going in the dirt basement of a hotel. I had tried to light a barrel(桶) of paint but couldn't really get a good fire going. The smoke got pretty bad, though, and when I made my exit, a crowd and the police were there to greet me. The policemen took my matches and drove me home.

    Mum and Dad were occupied in the garden and Dad told the police to keep me, and they did! I had a tour of the prison before Mum rescued me. I hadn't turned 5 yet.

    As I entered kindergarten, the serious cold began to set in. Would it surprise you to know that I soon left part of my tongue on a metal handrail at school?

    As for Leonhard Seppala, famous as a dog sledder(驾雪橇者), I think I knew him well because I was taken for a ride with his white dog team one Sunday. At the time I didn't realize what a superstar he was, but I do remember the ride well. I was wrapped(包裹) heavily and well sheltered from the freezing and blowing weather.

    In 1950, we moved back to Coeur d'Alene, but we got one more Alaskan adventure when Leonhard invited us eight years later by paying a visit to Idaho to attend a gathering of former neighbors of Alaska.