题干

由1分子磷酸、1分子碱基和1分子化合物a构成了化合物b,如右图所示,则叙述正确的是    

A:若m为腺嘌呤,则b肯定为腺嘌呤脱氧核苷酸

B:在禽流感病毒、幽门螺杆菌体内b均为4种

C:ATP脱去两个磷酸基团,可形成

D:若a为脱氧核糖,则由b构成的核酸完全水解,得到的化合物最多有8种

上一题 下一题 0.0难度 选择题 更新时间:2012-05-22 06:28:09

答案(点此获取答案解析)

C

同类题4

阅读理解

    If you want to live longer and lower the risk of heart disease, a move to the mountains may help. Research by scientists in Greece shows that living in the mountains is good for the heart and longevity(长寿). People living at higher altitude(海拔) have lower possibility of dying from heart disease than those closer to sea level, even if they have factors that could increase their risk. "Residence in mountainous areas seems to have a 'protective effect' from heart disease," said Dr Nikos Baibas of the University of Athens. He and his colleagues suspect that the increased exercise from walking up mountainous area gives the heart a good workout and enables it to cope with lower levels of oxygen.

    Researchers studied the health records and death rates of 1,150 Greeks who lived in three villages near Athens over 15 years. One village was 1,000 meters above sea level and the other two were in low-lying areas. Although men and women living in the mountainous village had higher blood pressure rates and other risk factors than people in the other villages, they had a lower rate of death from heart disease and other causes after a fifteen year follow-up." The contrast was more evident among men than among women," Baibas added in a report in the Journal of Epidemiology and Community Health. Heart disease is one of the world's top killers. Smoking, high blood pressure, raised cholesterol levels, being overweight and a family history of the illness increase the possibility of developing the disease.