题目

防御素是一类具有抗菌活性的蛋白质，广泛存在于动物和植物中。有关说法错误的是A. 将防御素溶于NaCI溶液中不会造成其生物学活性的丧失B. 该蛋白质是在核糖体上合成，若破坏核仁将影响防御素的形成C. 蛋白质遇高温变性后与双缩脲试剂不会变紫色D. 防御素在生物体内具有免疫的作用 答案：【答案】C【解析】关于蛋白质1、元素组成：主要由C、H、O、N等元素组成。2、基本单位：氨基酸。3、合成方式及场所：在核糖体上以脱水缩合的方式进行。4、检验方法：蛋白质与双缩脲试剂后产生紫色反应。5、蛋白质的多样性原因：组成蛋白质的氨基酸的种类、数目、排列顺序不同，肽链的盘曲、折Last year,around Labor Day,I read a " Happy Ad" in our local newspaper.There was a lady in a local nursing home for the aged,who was celebrating her 90th birthday and her family wanted everyone to know about it.It said that if you wanted to drop her a line,here was her address.So I did.I found a birthday card and dropped her a short note,wishing her a happy birthday.A week or so later,someone knocked at my front door.I opened the door and found a middle-aged man standing on my doorstep.He introduced himself as the son of this woman to whom I had sent the card.He explained that he just wanted to drop by in person and thank me for sending such a nice card to his mom.Apparently,like many older folks,she did not receive much mail and was quite excited to receive mine.I just didn't know what to say.I told him it was my pleasure and that I hoped his mom had enjoyed her birthday.That year,I did not send out any Christmas cards,except to this lovely old lady in the nursing home.I just told her that I was thinking about her and hoped that she had a nice holiday.I sent her a holiday card and also a couple of notes in between.I just thought she might like to have someone write to her,to get some mails.She passed away a couple of months ago.I never met this lady,but I did keep her and her family in my thoughts. I dropped them a line of sympathy.I hope that my few little notes were enough to brighten a couple of her days here on earth.1.The old lady lived .A. at her son's home B. at her own homeC. in a senior citizen's home D. in a center of the local newspaper2.From the text,we can know that .A. the son of this old lady opened the door to meet the authorB. the lovely old lady received many birthday cards at the age of 90C. the family wanted the author to celebrate the old lady's 90th birthdayD. the author sent another card with notes to the old lady on Christmas Day3.What is the passage mainly about?A. A moving story of an old lady.B. A worthy deed from the caring author.C. A happy advertisement about the family.D. A perfect plan from the considerate son.