题干

下图的基因模型为控制某种酶的基因内部和周围的DNA片段情况。距离以千碱基对(kb)表示,但未按比例画出,基因长度共8kb,人为划分a-g共7个区间,转录直接生成的mRNA中d区间所对应的区域会被加工切除,成为成熟的mRNA。下列分析正确的是(    )

A:起始密码子对应位点是RNA聚合酶结合的位点

B:终止密码子是最后一个氨基酸结合到核糖体的位点

C:该酶是由299个氨基酸组成的

D:mRNA上某一特定位点需要的氨基酸均可以由几种特定的tRNA将它转运到核糖体上

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C

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                                                                                   Growing Up in Australia

    Since 2004, Australia has been holding its largest study of children's health ever. This project, “Growing Up in Australia,” is following two groups of children from early childhood until they become adults. The project is being supported by the Australian government and involves hundreds of researchers visiting the homes of 10,000 children. Researchers hope to find a relationship between the children's future behavior and their health, education, and family environments.

    When the study began, the first group of children was aged 0-1, while the second group was aged 4-5. In order to make sure that children from every kind of environment and background were chosen, the study found volunteers from each area. Some volunteers are in the countryside, while others are in big cities. The volunteers for both groups were chosen from a variety of different social and ethnic (种族) backgrounds.

    The researchers visit the participants' (参与者) homes every two years to gather information. They interview the parents about parenting styles and the child's daily activities. They also take measurements of the children's health and how well the children perform in school. The researchers also collect information such as the income of the child's family, the school the child attends, and the kind of community (社区) in which the child lives. They plan to use the information to improve children's lives.

    Researchers have already begun to publish some interesting results. For instance, after examining information from the second group of children when they were 10-11 years old, researchers found that children who spend a lot of time doing organized activities, such as music lessons or sports, have good control of their emotions and behavior. The study also found that they are able to complete their homework without their parents around. On the other hand, it found that children who watch a lot of television get upset easily and have worse behavior. The Australian government is now using this information to make better educational and health policies for Australian children.