什么是热原？简述热原的性质、热原的污染途径及除去热原的方法。

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问题问答题简答题

答案

参考答案：

热原是微生物产生的内毒素，是由磷脂、脂多糖和蛋白质组成的复合物，其中脂多糖是活性中心。

热原的性质：①耐热性；②水溶性；③不挥发性；④滤过性；⑤吸附性；⑥可被化学试剂破坏；⑦超声波等也能破坏热原。

污染热原的途径：①经溶剂带入；②从原辅料中带入；③经容器、用具、管道和装置等带入；④经制备过程带入；⑤灭菌后带入；⑥经输液器带入。

除去热原的方法：①容器上热原的除去，可用高温法或酸碱法；②水中热原的除去，可用离子交换法、凝胶过滤法、蒸馏法、反渗透法等；③溶液中热原的除去，可用吸附法和超滤法。

阅读理解

I grew up in a small town. My father raised chickens and ran a construction company. I was only 10 years old when my dad gave me the responsibility of feeding the chickens and cleaning up the stable. He believed it was important for me to have those jobs to learn responsibility. Then, when I was 22, I found a job in Natchbill at a country music club called the Natchbill Palace, I washed dishes and cooked from 4:00 p.m to 9:00 p.m and then went on stage and sang until 2:00 in the morning. It wasn’t long before I became known as a singing cook. I had been rejected(拒绝) so many times by record companies that it was hard not to be discouraged. One night, a woman executive(董事) from a company named Warner Brothers Records came to hear me sing. When the show was over, we sat down and talked and after she left, I said to myself it was one more rejection. A few weeks later, my manager received a phone call—Waner Brothers wanted to sign me to a record deal. Soon after, I release(发行) my first record in June 1986. It sold over 2 million copies. My best efforts had gone into every job I’ve ever held. It was the sense of responsibility that made me feel like a man. Knowing that I had done my best filled me with pride. I still feel that way today, even though I have become a well-known singer.

小题1:Why was the writer once known as the singing cook?

A．Because he was a cook at a country –music club.

B．Because he sang for guests while he worked as a cook.

C．Because he often sang while cooking.

D．Because he liked singing better than cooking.小题2:Who first recognized his talents and helped make his career successful?

A．Warner Brothers

B．His manager

C．His father

D．A business woman小题3:What made the writer proud of himself?

A．His ability to live independently.

B．His sense of responsibility in whatever he did.

C．His courage in the face of rejections.