问题
选择题
已知AUG、GUG为起始密码，UAA、UGA、UAG为终止密码。某原核生物的一个信使RNA碱基排列顺序如下：A-U-U-C-G-A-U-G-A-C……（40个碱基）……C-U-C-U-A-G-A-U-C-U，此信使RNA控制合成的蛋白质含氨基酸的个数为 [ ]
A．20个
B．15个
C．16个
D．18个
答案
答案：C
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已知AUG、GUG为起始密码，UAA、UGA、UAG为终止密码。某原核生物的一个信使RNA碱基排列顺序如下：A-U-U-C-G-A-U-G-A-C……（40个碱基）……C-U-C-U-A-G-A-U-C-U，此信使RNA控制合成的蛋白质含氨基酸的个数为 [ ]
A．20个
B．15个
C．16个
D．18个
答案：C
| 完型填空。从每题的三个选项中选出可填入相应的空白处的最佳答案。 |
| Once a rich woman invited Martin Brown, a famous singer to sing for her friends. But she 1 him to have dinner with them. She told him to eat 2 the servants (仆人). After the meal Martin stood up and said to the servants."Now, my good friends, I 3 for you." He sang several songs and the servants 4 quite pleased. Then the rich woman asked 5 to come to the sitting-room." We are waiting for your songs. 6 you ready?" the woman asked. "I am 7 ," Martin said. "I have sung already. I usually sing 8 in one evening, and I can't sing 9 ." And with a polite (礼貌) " 10 ", he left the rich woman's house. |
| ( )1. A. doesn't invite ( )2. A. with ( )3. A. sang ( )4. A. was ( )5. A. the servant ( )6. A. Were ( )7. A. sad ( )8. A. one ( )9. A. two ( )10. A. Good night | B. don't invite B. for B. shall sing B. were B. the friend B. Is B. sorry B. once B. once B. Good afternoon | C. didn't invite C. at C. sing C. are C. the singer C. Are C. glad C. twice C. twice C. Good day |