您所在的当前位置：高中生物试题 >

蛋白质的结构和功能

> 现有1000个氨基酸，其中氨基有1020个，羧基有1050个，则由这些氨基酸合成的4条多肽链中共有肽键、氨基、羧基的数目是 [ ] A．999、1016、1046 B．996、1、1 C．996、24、54 D．996、1016、1046

问题：

发布时间：2024-09-09

现有1000个氨基酸，其中氨基有1020个，羧基有1050个，则由这些氨基酸合成的4条多肽链中共有肽键、氨基、羧基的数目是
[ ]
A．999、1016、1046
B．996、1、1
C．996、24、54
D．996、1016、1046

参考答案：

提问用户：Pw***oE2

可能感兴趣的题目：

1 在一次实验时某同学用游标卡尺测量（如图），示数为_______________cm。在一次实验时某同学用螺旋测微器测量（如图），示数为________mm。
2 阅读理解。 When we can see well, we do not think about our eyes often. It is only when we can not see perfectly that we come to see how important our eyes are. People who are nearsighted can only see things that are very close to their eyes. Many people who do a lot of close work, such as writing and reading, become nearsighted. Then they have to wear glasses in order to see distant things clearly. People who are farsighted face just the opposite problem. They can see things that are far away, but they have difficulty reading a book unless they hold it at arm"s length. If they want to do much reading, they must get glasses too. Other people do not see clearly because their eyes are not exactly the right shape. This, too, can be corrected by glasses. Some people"s eyes become cloudy because of cataracts. Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them. When night falls, colors become fainter to the eyes and finally disappear. After your eyes have grown used to the dark, you can see better if you use the side of your eyes rather than the centers. Sometimes, after dark, you see a small thing to one side of you, which seems to disappear if you turn your head in its direction. This is because when you turn your head, you are looking at the thing too directly. Men on guard duty sometimes think they see something moving to one side of them. When they turn to look straight at it, they can not see it any more, and they believe they were mistaken. However, this mistake happens because the center of the eye, which is very sensitive in daylight, is not as sensitive as the sides of the eye after dark. 1. We don"t know that our eyes are of great importance until _____. [ ] A. we think about our eyes B. we cannot see clearly C. we wear glasses D. we have to do much reading 2. According to the passage, a _____ is more likely to be nearsighted. [ ] A. student B. doctor C. guard D. painter 3. People who are farsighted _____. [ ] A. can do a lot of close work without glasses B. can only see things that are very close to their eyes C. have difficulty reading a book if they hold it at arm"s length D. can correct their eyes by glasses 4. To see a small thing at night, it is better to look _____. [ ] A. with wide open eyes B. with half shut or narrowed eyes C. straight at it D. in a slightly different direction
3 下表为某国际经济组织对中国的援助战略和主题内容，该国际经济组织是年份援助战略主题展开 2002 农村／农村社会向城镇／工业社会转型解决贫困人口和贫困地区的问题中国环境技术援助推动环境的可持续性 A．世界银行 B．国际货币基金组织 C．亚太经合组织 D．世界贸易组织
4 在100mL的混合酸溶液中，硝酸的物质的量浓度为0.5mol/L，硫酸的物质的量浓度为0.15mol/L，向其中加入5.76g铜粉，微热，使其充分反应．（1）溶液中Cu 2+的物质的量浓度是______．（2）若要使5.76g铜粉恰好完全溶解，且溶液中只存在一种盐．则原溶液中硝酸的物质的量是______；硫酸的物质的量是______．
5 （10分）青藏铁路通车标志着西藏旅游进入了一个新时代。读下列图文资料，回答问题。（注：图一反映了西藏近25年来国内旅游者和地区生产总值的变化情况。图二反映了入藏游客量变化的季节性特征。） (1)旅游资源丰富，青藏铁路沿线能看到的独特自然景观有（回答2种）；西藏地区被列为世界文化遗产的是。 (2)下列对西藏地区叙述错误的是（多项选择）。 A．太阳紫外线辐射强，日温差大 B．气候寒冷，生态环境脆弱 C．北部降水丰富，多雨雪天气 D．水力资源、地热资源丰富 E．空气稀薄缺氧 F．高原湖泊多 G．气温年较差大 (3)从1980年～2005年，西藏国内旅游者的数量变化状况是；入藏游客数量的年内变化特点是。 (4)随着西藏旅游业的发展，有关人士提出制订西藏旅游环境容量的建议。对此，你认为是否有必要？为什么？
6 在标准状况下，将O 2与NO按3∶4的体积比充满一个干燥烧瓶，将烧瓶倒置于水中，瓶内液面逐渐上升，(假设烧瓶内溶液不向外扩散)最后烧瓶内溶液的物质的量浓度为（） A．0.045 mol·L-1 B．0.036 mol·L-1 C．0.026 mol·L-1 D．0.030 mol·L-1
7 2014年央视春晚，由匈牙利人演绎的舞蹈《符号中国》，以其独特的创意和充满中国元素的画面，令我们倍感亲切又耳目一新。这说明 ①各国文化既相互交流又逐渐趋同 ②文化既是民族的又是世界的 ③理论创新是社会变革和发展的先导 ④创新推动人类思维和文化的发展 A．①② B．③④ C．①③ D．②④
8 —The railway station, please. I have to be there in ten minutes. —______, but I’ll do my best. A．No problem B．OK C．I can’t promise D．I can’t do that
9 AgCl固体溶解在水中形成饱和溶液（AgCl固体有剩余），下列说法正确的是（） A．AgCl沉淀生成和沉淀溶解不断进行，但速率相等 B．在此饱和溶液中加水，KSP（AgCl）增大 C．在此饱和溶液中加浓的Na2S溶液，生成黑色沉淀 D．向AgCl饱和溶液中加入NaCl固体，c（Ag+）不变
10 在草→兔→狐食物链中，狐所处的消费者级别及营养级分别是 [ ] A．初级消费者、第二营养级 B．次级消费者、第三营养级 C．三级消费者、第二营养级 D．初级消费者、第三营养级