问题
单项选择题
去甲肾上腺素可来自
A．色氨酸
B．酪氨酸
C．赖氨酸
D．脯氨酸
E．苏氨酸
答案
参考答案：B
解析： 苯丙氨酸可生成酪氨酸，酪氨酸经羟化成多巴，再脱羧成多巴胺，多巴胺侧链羟化即成去甲肾上腺素。
搜题请搜索小程序“爱下问搜题”
去甲肾上腺素可来自
A．色氨酸
B．酪氨酸
C．赖氨酸
D．脯氨酸
E．苏氨酸
参考答案：B
解析： 苯丙氨酸可生成酪氨酸，酪氨酸经羟化成多巴，再脱羧成多巴胺，多巴胺侧链羟化即成去甲肾上腺素。
| 阅读下面短文，掌握其大意，然后从各小题所给的四个选项中选出最佳选项。 | |||
| Sometimes it's easy to forget that we live in neighborhoods. A picnic 1 a few activities can be fun. Your neighbors will 2 that they want to do things togethermore often. The game of "Getting to 3 You" is a great way for neighbors to learn more about each other.You can 4 by eating at picnic tables. You have to choose an"asker" to ask 5 to the neighbors． The question could be "Can you playins truments (乐器)?" 6 you can't play any instrument, sit down. Then the "asker" will ask,"Can you play just 7 instrument?" If you can play just oneinstrument, please sit down.If the person can play the most instruments, he or she will be the 8 one standing. And he 9 she is tne Wlnner．Neighborhood 10 are not just lots of fun. They also helpbuild a safe living place. | |||
| ( )1. A. in ( )2. A. hear ( )3. A. Know ( )4. A. decide ( )5. A. questions ( )6. A. Or ( )7. A. two ( )8. A. first ( )9. A. so ( )10. A. houses | B．on B. find B. Play B. order B. directions B. Or B. one B. second B. but B. ideas | C. with C．smell C. Bring C．give C．price C. If C. five C．third C．or C．sports | D. to D. smile D. Put D. begin D. ways D. Unless D. three D. last D. and D. picnics |