问题 单项选择题

下列关于染色体、DNA、基因的表述正确的是()。

A.有丝分裂间期完成染色体复制,使染色体和DNA数量加倍

B.一条染色体中,构成基因的碱基总数和构成DNA的碱基总数相等

C.DNA分子的一条单链中相邻的两个碱基通过氢键相连

D.链霉素能让核糖体与单链DNA结合并进行翻译.遗传信息从DNA流向蛋白质

答案

参考答案:D

解析:有丝分裂间期完成染色体复制,使DNA数量加倍,染色体数量不变,A错误;由于基因是有遗传效应的DNA片段,构成基因的碱基总数小于构成DNA的碱基总数,B错误;DNA分子两条链中的碱基对之间通过氢键相连,DNA分子中的一条单链中相邻的两个碱基间不是通过氢键相连,而是以脱氧核糖-磷酸-脱氧核糖相连,C错误;核糖体与单链DNA结合,进行蛋白质的合成,遗传信息从DNA流向蛋白质,D正确。

多项选择题
阅读理解

阅读理解。

     In 1890 William James, the American philosopher and physician and one of the founders of modern

psychology, defined psychology as"the science of mental life" and this definition provides a good starting

point for our understanding even today. We all have a mental life and therefore have some idea about what

this means, even though it can be studied in rats or monkeys as well as in people and the concept remains

difficult to understand.

     Like most psychologists, William James was particularly interested in human psychology, which he

thought consisted of certain basic elements: thoughts and feelings, a physical world which exists in time

and space, and a way of knowing about these things. For each of us, this knowledge is primarily personal

and private" It comes from our own thoughts, feelings and experience of the world, and may or may not

be influenced by scientific facts about things. For this reason, it is easy for us to make judgments about

psychological matters using our own experience as a standard. We behave as amateur psychologists when

we offer opinions on complex psychological phenomena. However, problems arise when two people

understand these things differently. Formal psychology attempts to provide methods for deciding which

explanations are most likely to be correct, or for determining the circumstances under which each applies.

The work of psychologists helps us distinguish between inside information, which is subjective, and may

be prejudiced and unreliable, and the facts: between our predictions and what is"true" in scientific terms.

     Psychology, as defined by William James, is about the mind or brain, but although psychologists do study

the brain, we do not understand nearly enough about its workings to be able to comprehend the part that it

plays in the experience and expression of our hopes, fears, and wishes, or in our behaviour during experiences

as varied as giving birth or watching a football match. Indeed, it is rarely possible to study the brain directly.

So, psychologists have discovered more by studying our behaviour, and by using their observations to obtain

hypotheses (假设) about what is going on inside us.

1. The first paragraph is mainly about _____.

A. the founder of modern psychology

B. the definition of psychology

C. the complexity of psychology

D. the influence of psychology

2. From Paragraph 2, we can know that problems arise because _____.

A. of the difference between inside information and the facts

B. of different thoughts and feelings about psychology

C. people usually make judgments based on their own ideas

D. amateur psychologists cannot use scientific terms

3. According to the passage, psychologists study the brain mainly _____.

A. in a direct way

B. with their own experience

C. by observing how it works

D. by watching people's behaviour

4. Which of the following can be the first sentence in the fourth paragraph?

A. Psychology is also about the ways people use their mental abilities to operate in the world around them.

B. William James is considered to be the greatest psychologist in the 1890s.

C. Psychology suggests that living beings adapt to a changing environment so that they can survive.

D. It is important for psychologists, as well as ordinary people, to be aware of the reasons.