问题 单项选择题 A1型题

人体排泄的嘌呤核苷酸分解代谢的特征性终产物是()

A.尿素

B.尿酸

C.肌酐

D.β-丙氨酸

E.黄嘌呤

答案

参考答案:B

解析:细胞内的核苷酸首先在核苷酸酶作用下水解成核苷,再经核苷磷酸化酶催化生成游离的碱基与1-磷酸核糖。嘌呤碱基可以经补救合成途径用于合成新的核苷酸,也可以最终氧化成尿酸随尿液排出体外。

阅读理解

No one wants to look silly or do the wrong thing at a new job. It is important to make the right impression(印象) from the first day. You’ll face new people. You will be in a new place.

It may be difficult to know what to do. Here are five tips to help you make it through the first days at a new job:

1. First impressions can last forever. Make sure you make a good one. Before your first day, find out if your new job has a dress code (rules about what you can wear to work). If so, be sure to follow it. No matter what, always be neat and clean.

2. Get to work on time. Give yourself an extra 15 minutes to make sure you arrive on time.

3. Pay attention to introductions. One of the first things that your supervisor may do is to introduce you to co-workers. These co-workers will be important to you. They are the ones who will answer your questions when the boss is not around.

4. Ask plenty of questions. Make sure that your supervisor has told you what is expected of you. If he or she has not told you your duties, ask for a list. Set daily and weekly goals for yourself.

5. Never be the first one to leave. Watch what your co-workers do around quitting time (下班时间).  It does not look good for you to be eager(急切) to leave.

小题1: Before you arrive at work, you should __________.

A.dress in a right way

B.introduce yourself

C.know your duties

D.know your co-workers well小题2: According to the passage, which of the following statements is True?

A.You should be the first one to arrive at work.

B.You should ask your co-workers for your duties.

C.You should not be eager to go back home.

D.You are required to arrive 15 minutes earlier.小题3:According to the passage, your supervisor is most likely your __________.

A.visitor

B.teacher

C.workmate

D.leader

单项选择题