【多选题】
锤头结构（hammerhead structure）___
A. 是不依赖Rho转录终止的mRNA上的3’端结构
B. 可以停止RNA聚合酶前移
C. 是核酶的共有结构
D. 其中某些碱基必须在特定位置上出现
E. 可以促进ATP释放能量
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相关试题
【多选题】
关于RNA___
A. mRNA带有遗传密码
B. tRNA是分子量较小的RNA
C. rRNA是蛋白质合成的场所
D. 胞浆中只有mRNA
E. snRNA是mRNA的前身
【多选题】
1953年生物化学的重大突破有___
A. Kornberg发现DNA聚合酶
B. Watson Crick确立双螺旋结构
C. Sanger测出胰岛素一级结构
D. Nirenberg确立遗传密码
E. Meselson-Stabl证实半保留复制
【多选题】
参与蛋白质生物合成的有___
A. mRNA
B. 核糖体
C. 转位酶
D. 连接酶
E. 转氨酶
【多选题】
DNA模板可直接用于___
A. 转录
B. 翻译
C. 复制
D. 核苷酸合成
E. 引物合成
【多选题】
遗传密码___
A. 20种氨基酸共有64个密码子
B. 碱基缺失、插入可致框移突变
C. AUG是起始密码
D. UUU是终止密码
E. 一个氨基酸可有多达6个密码子
【多选题】
遗传密码的特性有___
A. 低等生物和人类共用一套密码
B. 不为任何氨基酸编码的密码子有4个
C. 密码和反密码辨认时不严格的配对称为简并性
D. UAA、UAG、UGA是终止密码
E. 点突变（错配）可引起读码框移
【多选题】
翻译过程需要消耗能量（ATP或GTP）的反应有___
A. 氨基酸和tRNA结合
B. 密码子辨认反密码子
C. 氨基酰-tRNA进入核糖体
D. 核糖体大、小亚基结合
E. 肽键生成
【多选题】
tRNA能够成为氨基酸的转运体、是因为其分子上有___
A. -CCA-OH 3’末端
B. 3个核苷酸为一组的结构
C. 稀有碱基
D. 反密码环
E. 假腺嘌呤环
【多选题】
蛋白质生成合成的延长反应包括下列哪些反应？___
A. 起始
B. 终止
C. 转位
D. 成肽
E. 转化
【多选题】
干扰素的作用___
A. 诱导eIF2磷酸化的蛋白激酶
B. 间接诱导核酸内切酶
C. 抗病毒
D. 激活免疫系统
E. 抑制转肽酶
【多选题】
关于RNA___
A. mRNA带有遗传密码
B. tRNA是分子量较小的RNA
C. rRNA是蛋白质合成的场所
D. 胞浆中只有mRNA
E. snRNA是mRNA的前身
【多选题】
1953年生物化学的重大突破有___
A. Kornberg发现DNA聚合酶
B. Watson Crick确立双螺旋结构
C. Sanger测出胰岛素一级结构
D. Nirenberg确立遗传密码
E. Meselson-Stabl证实半保留复制
【多选题】
参与蛋白质生物合成的有___
A. mRNA
B. 核糖体
C. 转位酶
D. 连接酶
E. 转氨酶
【多选题】
DNA模板可直接用于___
A. 转录
B. 翻译
C. 复制
D. 核苷酸合成
E. 引物合成
【多选题】
遗传密码___
A. 20种氨基酸共有64个密码子
B. 碱基缺失、插入可致框移突变
C. AUG是起始密码
D. UUU是终止密码
E. 一个氨基酸可有多达6个密码子
【多选题】
遗传密码的特性有___
A. 低等生物和人类共用一套密码
B. 不为任何氨基酸编码的密码子有4个
C. 密码和反密码辨认时不严格的配对称为简并性
D. UAA、UAG、UGA是终止密码
E. 点突变（错配）可引起读码框移
【多选题】
翻译过程需要消耗能量（ATP或GTP）的反应有___
A. 氨基酸和tRNA结合
B. 密码子辨认反密码子
C. 氨基酰-tRNA进入核糖体
D. 核糖体大、小亚基结合
E. 肽键生成
【多选题】
tRNA能够成为氨基酸的转运体、是因为其分子上有___
A. -CCA-OH 3’末端
B. 3个核苷酸为一组的结构
C. 稀有碱基
D. 反密码环
E. 假腺嘌呤环
【多选题】
蛋白质生成合成的延长反应包括下列哪些反应？___
A. 起始
B. 终止
C. 转位
D. 成肽
E. 转化
【多选题】
干扰素的作用___
A. 诱导eIF2磷酸化的蛋白激酶
B. 间接诱导核酸内切酶
C. 抗病毒
D. 激活免疫系统
E. 抑制转肽酶
【多选题】
基因表达调控的意义是___
A. 适应环境、维持生存
B. 维持细胞生长、分裂
C. 调节细胞发育、分化
D. 维持个体生长、发育
E. 调节组织、器官的形成
【多选题】
下述蛋白质基因表达具有组织特异性的是___
A. 磷酸甘油醛脱氢酶
B. 胰岛素
C. 血红蛋白
D. 丙酮酸脱氢酶
E. HMG CoA裂解酶
【多选题】
基因表达的终产物可以是___
A. 蛋白质
B. 多肽链
C. 核酸
D. 脱氧核糖核酸
E. 核糖核酸
【多选题】
一个操纵子（元）必含有___
A. 一个编码基因
B. 数个编码基因
C. 一个启动序列
D. 数个启动序列
E. 一个操纵序列
【多选题】
在lac操纵子（元）机制中起调控作用的是___
A. I基因
B. Z基因
C. Y基因
D. O序列
E. P序列
【多选题】
通常组成最简单的启动子的元件有___
A. TATA盒
B. GC盒
C. CAAT盒
D. 转录起始点
E. UAS序列
【多选题】
下述基因表达调控机制涉及阻遏蛋白的是___
A. 乳糖操纵子
B. 阿拉伯糖操纵子
C. 色氨酸操纵子
D. SOS反应
E. 沙门氏菌相变异
【多选题】
在乳糖操纵子机制中起正性调节的因素是___
A. 阻遏蛋白去阻遏
B. cAMP水平升高
C. 葡萄糖水平升高
D. cAMP水平降低
E. 葡萄糖水平降低
【多选题】
属于基因表达终产物的是___
A. tRNA
B. mRNA
C. rRNA
D. 蛋白质
E. 多肽链
【多选题】
自然界基因转移可能伴发基因重组的有___
A. 接合作用
B. 转化作用
C. 转导作用
D. 转座
E. 以上都不是
【多选题】
2．在分子克隆中，目的DNA可来自___
A. 原核细胞染色体DNA
B. 真核细胞染色体DNA
C. 真核细胞mRNA反转录获得的cDNA
D. 聚合酶链式反应
E. 人工合成的DNA
【多选题】
3．从基因组DNA文库或cDNA文库分离、扩增某一感兴趣基因的过程就是___
A. 基因克隆
B. 分子克隆
C. 重组DNA技术
D. 构建基因组DNA文库
E. 构建cDNA文库
【多选题】
⒋ 可用作克隆基因载体的DNA有___
A. 细菌质粒DNA
B. 噬菌体DNA
C. 病毒DNA
D. 酵母人工染色体
E. 真核细胞基因组DNA
【多选题】
⒌ 将重组DNA分子导入受体细菌的方法有___
A. 接合
B. 转座
C. 转化
D. 转染
E. 感染
【多选题】
⒍ 下述序列属于完全回纹结构的是___
A. 5′…CCTAGG…3′
B. 5′…CCAAGG…3
C. 5′…CCTTGG…3
D. 5′…CGAACG…3
E. 5′…CGTTCG…3
【多选题】
⒎ 下述操作可能用于DNA克隆过程的是___
A. DNA的制备和酶解
B. 不同来源DNA的拼接
C. 核酸分子杂交
D. 细菌的生长和繁殖
E. RNA的制备
【多选题】
⒏ 关于质粒DNA的叙述正确的是___
A. 是基因组DNA的组成部分
B. 具有独立复制功能
C. 具有编码蛋白质的功能
D. 含有感兴趣的目的DNA
E. 含有各种抗生素抗性基因
【多选题】
蛋白C系统包括___
A. 清蛋白
B. 蛋白S
C. 蛋白C
D. 球蛋白
E. 蛋白C抑制物
【多选题】
血红素合成的特点是___
A. 合成的主要部位是骨髓和肝脏
B. 合成原料是甘氨酸、琥珀酰CoA 及Fe2+等
C. 合成的起始和最终过程均在线粒体中
D. ALA脱水酶是血红素合成的限速酶
E. 合成中间步骤在胞液中
【多选题】
依赖于维生素K的凝血因子是___
A. 因子Ⅺ
B. 因子Ⅶ
C. 因子Ⅱ
D. 因子Ⅸ
E. 因子Ⅵ
推荐试题
【填空题】
54.混凝土浇筑包括___和___两个过程。
【填空题】
55.无粘结预应力混凝土结构在张拉后容许预应力筋对周围混凝土发生___滑动。
【填空题】
56.斜拉桥是新型的桥梁形式，这种形式大桥的主桥分为___和___两大部分。
【填空题】
57.___和___是国际通行的工程建设项目组织实施方式。
【填空题】
58.BIM 中的图形是赋予了___属性的实体。
【填空题】
59.BIM 是指建筑物在设计和建造过程中，创建和使用的“___”。
【单选题】
The word "wag" (Line 1, Para.1) most probably means _________.
A. move
B. shake
C. bite
D. play
【单选题】
The video cameras were used to catch the dogs' responses because ___________.
A. the dogs were put in the wooden boxes
and tested one at a time
B. it was easier to catch the dogs’s response changes in the tail wagging
C. they enabled the dogs’owners to know
about their dogs’; habit
D. the dogs wagged their tails in different
directions when they were in different
moods
【单选题】
When there are no stimuli, a dog will ___________.___
A. wag to the right
B. no wag at all
C. wag to the left
D. wag to the left and then wag to the right
【单选题】
The purpose of doing the experiment is _________.___
A. to train dogs for their owners
B. to help dogs find companion
C. to help people choose their pet dogs
D. to help people judge the mood of dogs
【单选题】
The underlined word "they" in the last sentence refers to __________.___
A. the trainers
B. the systems
C. the researchers
D. the dogs
【单选题】
The new law passed in Rome will ________.___
A. help improve fishing environment
B. stop people from catching goldfish
C. guarantee better conditions for goldfish
D. discourage keeping goldfish at home
【单选题】
People in Rome believe that the civilization of a city can be judged by _________.___
A. awareness of animal protection
B. exchanges with other cities
C. protection of ancient ruins
D. recognition of animal lovers
【单选题】
The underlined word "compassion" in Para 2 is the closest in meaning to __________.___
A. support
B. pity
C. help
D. love
【单选题】
People may break the law in Turin if they ________.___
A. keep their dogs or cats in cars
B. shut their dogs home all day long
C. raise their cats near ancient ruins
D. feed homeless animals in car parks
【单选题】
We can infer from the passage that _________.___
A. the owners can leave their dogs in hot cars
B. the cat only lives in modern life
C. the new law can prevent cruelty to animals
D. the new law gives recognition to the
people who feed homeless cat
【单选题】
If a person finds getting up early a problem, most probably ________.___
A. he is a lazy person
B. he refuses to follow his own energy cycle
C. he is not sure when his energy is low
D. he is at his peak in the afternoon or evening
【单选题】
Which of the following may lead to family quarrels according to the passage?___
A. Unawareness of energy cycles.
B. Familiar monologues.
C. A change in a family member's energy cycle.
D. Attempts to control the energy cycle of other family members.
【单选题】
If one wants to work efficiently at his low point in the morning, he should __________.___
A. change his energy cycle
B. overcome his laziness
C. get up earlier than usual
D. go to bed earlier
【单选题】
You are advised to rise with a yawn and stretch because it will __________.___
A. help to keep your energy for the day's work
B. help you to control your temper early in the day
C. enable you to concentrate on your routine work
D. keep your energy cycle under control all day
【单选题】
Which of the following statements is NOT true?___
A. Getting off to work with a minimum effort helps save one's energy.
B. Dr. Kletman explains why people reach their peaks at different hours of day.
C. Habit helps a person adapt to his own energy cycle.
D. Children have energy cycles, too.
【单选题】
An effective way to prevent the burnout of young athletes is __________.___
A. to increase their sense of success
B. to make sports less competitive
C. to reduce their mental stress
D. to make sports more challenging
【单选题】
According to the passage sport is positive for young people in that __________.___
A. it can help them learn more about society
B. it enables them to find flaws in themselves
C. it teaches them how to set realistic goals for themselves
D. it can provide them with valuable experiences
【单选题】
Many coaches and parents are in the habit of criticizing young athletes __________.___
A. without realizing criticism may destroy their self-confidence
B. in order to make them remember life's lessons
C. believing that criticism is beneficial for their early development
D. so as to put more pressure on them
【单选题】
According to the passage parents and coaches should __________.___
A. help children to win every game
B. pay more attention to letting children enjoy sports
C. train children to cope with stress
D. enable children to understand the positive aspect of sports
【单选题】
The author's purpose in writing the passage is _________.___
A. to persuade young children not to worry about criticism
B. to stress the importance of positive reinforcement to children
C. to discuss the skill of combining criticism with encouragement
D. to teach young athletes how to avoid burnout
【单选题】
As pointed out at the beginning of the passage, people used to think that air pollution _______.___
A. cause widespread damage in the countryside
B. affected the entire eastern half of the United States
C. had damaged effect on health
D. existed merely in urban and industries areas
【单选题】
As to the greenhouse effect, the author ________.___
A. share the same view with the scientist
B. is uncertain of its occurrence
C. rejects it as being ungrounded
D. thinks that it will destroy the world soon
【单选题】
The underlined word "offset" in the second paragraph could be replaced by _________.___
A. slip into
B. make up for
C. set up
D. catch up with
【单选题】
It can be concluded that ____________.___
A. raising the world's temperature only a few degrees would not do much harm to life on earth
B. lowering the world's temperature merely a few degrees would lead major farming areas to disaster
C. almost no temperature variations have occurred over the past decade
D. the world's temperature will remain constant in the years to come
【单选题】
This passage is primarily about __________.___
A. the greenhouse effect
B. the burning of fossil fuels
C. the potential effect of air pollution
D. the likelihood of a new ice age
【单选题】
What is the major function of paragraph 1?___
A. To arouse the reader's concern.
B. To introduce the theme of the whole passage.
C. To summarize the whole passage.
D. To state the primary uses of TV.
【单选题】
Television, as a source of entertainment, is ________.___
A. not very convenient
B. very expensive
C. quite dangerous
D. relatively cheap
【单选题】
Why are some people against TV?___
A. Because TV programs are not interesting.
B. Because TV viewers are totally passive.
C. Because TV prices are very high.
D. Because TV has both advantages and disadvantages.
【单选题】
One of the most obvious advantages of TV is that _________.___
A. it keeps us informed
B. it is very cheap
C. it enables us to have a rest
D. it controls our lives
【单选题】
According to the passage, whether TV is good or not depends on ___________.___
A. its quality
B. people's attitude towards it
C. how we use it
D. when we use it
【单选题】
What regulation was issued by New York State concerning beverage containers?___
A. A fee should be charged on used containers for recycling.
B. Throwaways should be collected by the state for recycling.
C. Consumers had to pay for beverage containers and could get their money back on returning them.
D. Beverage companies should be responsible for collecting and reusing discarded plastic soda bottles.
【单选题】
The returned plastic bottles in New York used to _____________.___
A. be turned into raw materials
B. be separated from other rubbish
C. have a second-life value
D. end up somewhere underground
【单选题】
The key problem in dealing with returned plastic beverage containers is ______________.___
A. how to reduce their recycling costs
B. to sell them at a profitable price
C. how to turn them into useful things
D. to lower the prices for used materials
【单选题】
Recycling has become the first choice for the disposal of rubbish because ______________.___
A. recycling causes little pollution
B. other methods are more expensive
C. recycling has great appeal for the jobless
D. local governments find it easy to manage
