题干

研究发现,人类免疫缺陷病毒(HIV)携带的RNA在宿主细胞内不能直接作为合成蛋白质的模板.结合中心法则(下图),下列相关叙述不正确的是(    )

A:子代病毒蛋白质外壳的合成至少要经过④、②、③过程

B:进行①、②、③过程的原料来自于宿主细胞

C:通过④形成的DNA可以整合到宿主细胞的染色体DNA上

D:②、③过程分别在宿主细胞核内和病毒的核糖体上进行

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答案(点此获取答案解析)

D

同类题1

阅读下列短文,完成下列小题。

    “Save the whales!” That's what the picture on Jake Smith's bedroom wall said. Jake liked having a picture that said something important: that showed he cared. He just never expected to get a chance to save a real whale, one right in his own neighbourhood.

    It was a Saturday morning when the newspaper first reported the whales' coming. A group of the animals were swimming close to the beach in Jake's hometown. All the local people rushed out to the beach to see them. They were expecting a beautiful show, better than a movie, but nothing they’d have to do anything about.

    Then one whale swam in the direction, directly towards land. It came in with the waves, and when the waves receded. Its huge body on the sand. Suddenly, Jake and his family and all the others were no longer sightseers. They had to become rescuers. A few people ran towards the animal. They pushed and tried to force the whale back into the water, but it was no use.

    An animal rescue service team soon arrived in a truck with heavy lifting machinery, to help move the animal. Jack and his family couldn't do much on the beach, so they went back to their house and made sandwiches and hot tea for the rescuers. At least, Jake thought, they could help in some way.

    Back at the beach, they offered the food to the rescuers and were happy to see that it was needed. It was getting dark. Some people lined up their cars along the beach and shined the headlights on the sand. The rescuers would not give up. After trying many times they were finally able to lift the whale into the water. Everyone cheered when it headed out to sea. It swam out about a mile and then disappeared for a moment under the sea. Then, in what looked like a jump of joy, it rose high above the water—a thank-you to those who had worked so hard to save his life.