高二英语课外阅读

高二英语课外阅读材料（1）

（1）DNA—the Secret of Life

Part One

On February 28,1953, two scientists named James Watson and Francis Crick astonished the scientific community by saying, “We have discovered the secret of life.” It was true. Crick and Watson had found the answer to one of the most important questions of biology—how do living things reproduce themselves?

The answer is in a chemical in the human body called DNA. Every cell in our bodies contains our genes, which pass hereditary characteristics on to our children. Genes are made of the chemical DNA. Watson and Crick had succeeded in understanding the structure of DNA and how genes are able to reproduce themselves. The discovery of DNA has been called the most important biological work of the last 100 years. It has already had and will continue to have an enormous influence on our lives. We have already experienced the benefits in many areas.

Part Two

Story A

Ten years ago John Waters killed a man. Although the police questioned him,

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they did not arrest him. As a result, until recently Waters was a free man. But when he committed the murder, Waters left some of his own cells on his victim. Two months ago, scientists decided to examine these cells. They compared the DNA from these cells with the DNA of people they had questioned. John Waters’s DNA matched exactly. Waters is now in prison. Should DNA testing be made a standard procedure in criminal investigations?

Story B

Mike Heathers is a young, successful businessman. He and his wife, Julia, decided to have children. Mike and Julia visited a surgeon and told him they wanted a good-looking, very intelligent child. Two months later Julia had a small but very expensive operation, using a technology called genetic engineering. Nine months later, a highly intelligent, good-looking baby was born. But what about all those who cannot afford to pay for this operation?

Story C

Mark Sawyer is a top athlete, and he wants to stay that way. About six months ago, Mark secretly visited a surgeon, who performed an operation on him. During the operation, the surgeon inserted an animal gene into Mark that would make him run faster. After that Mark won all his races. He’s a world champion again—but should he be?

Story D

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Damian Peterson and his wife Clara are another couple that want to have children. But it is very likely that their child will be born with a terrible inherited illness. If so, the child will not live long. When Clara became pregnant, hospital tests showed that her child would have his illness. The couple decided to get rid of the unborn baby. Should this be allowed?

Part Three

Watson and Crick’s discovery about DNA was the beginning of enormous advances in the field of genetics. We can see the results in the world today. Stories A and D have actually happened many times. Stories B and C will become possible in the near future.

The new technology of genetic engineering means that scientists will soon be able to insert new genes into unborn babies, children or adults. These new genes will create new characteristics. The unborn baby will be cleverer. The adult will be able to run faster. A new future is approaching. But do we want it? Where are these scientific developments taking us?

If we start choosing the characteristics of our babies, we are altering nature in a very direct way. What might the consequences be? It is possible that we will create two kinds of people, genetically engineered people and ordinary people. And do we want to get rid of unborn babies because they have certain diseases or characteristics? On the other hand, we may soon be able to get rid of the disease---but keep the baby! Wouldn’t that be wonderful? But what about the

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athlete who secretly changes his genes? How will we know if someone has done this?

Genetics is a science that has already caused and will cause great changes in our lives. As a result, there are many important issues to discuss. Let us hope that we can find the right answers.

参考生词：

hereditary /h red t ri/ adj.遗传的

question / kwest n/ v. 盘问，审问，询问

investigation /in vesti gei n/ n. 调查

alter / o lt / v. 使变样， 改变

consequence / konsikw ns/ n. 结果，影响

阅读任务：

Task 1: Read part 1 of the passage and answer the questions.

1.Why did Watson and Crick say, “We have discovered the secret of life?”

2.Why is the discovery of DNA very important?

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Task 2:Read part 2 of the passage and get the main idea of each story.

Story one:

Story two:

Story three:

Story four:

Task 3:Read part 3 of the passage and answer the questions.

1.Do you think stories A—D in part 2 are true?

2.What will genetic engineering help scientists to do in the near future?

3.What will happen if we start choosing the characteristics of our babies?

4.What might the consequences be?

Task 4:Look at the words and expressions from the passage and choose correct answers.

commit a murder couple hereditary perform an operation

pregnant question reproduce victim

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1. …how do living things reproduce themselves? This means___________.

(a ) to have babies or produce young plants

( b) to feed themselves.

2. …our genes , which pass hereditary characteristics on to our children. This means_____.

( a ) new

(b) inherited from parents.

3 Although the police questioned him …This means___________.

( a ) to wonder about someone

(b) to ask someone questions

4 But when he committed the murder…This means___________.

( a) killed the man

(b) saw the dead man.

5 . …waters left some of his own cells on his victim. This means___________.

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(a ) the person he attacked

( b) his own clothes

6 About six months ago, Mark secretly visited a surgeon, who performed an operation on him. This means________

(a ) Mark had an operation

( b) the surgeon said Mark should have an operation

7. Damian Peterson and his wife Clara are another means________.

( a ) two people who are married

( b) example

8. When Clara became pregnant …This means_________

( a ) became worried

(b) was going to have a baby.

Task 5:Discussion:

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couple…This

What is your opinion about the developments in genetics(遗传学）in general?

（2）DNA Fingerprinting

DNA is the genetic material found within the cell nuclei of all living things. 1In mammals the strands of DNA are grouped into structures called chromosomes. 2With the exception of identical siblings (as in identical twins)，the complete DNA of each individual is unique.3DNA fingerprinting is sometimes called DNA typing. It is a method of identification that compares bits of DNA.

A DNA fingerprint is constructed by first drawing out a DNA sample from body tissue or fluid such as hair, blood, or saliva. The sample is then segmented using enzymes, and the segments are arranged by size. The segments are marked with probes and exposed on X-ray film，where they form a pattern of black bars — the DNA fingerprint. If the DNA fingerprints produced from two different samples match，the two samples probably came from the same person.

DNA fingerprinting was first developed as an identification technique in 1985. Originally used to detect the presence of genetic diseases，it soon came to be used in criminal investigations and legal affairs. 4The first criminal conviction based on DNA evidence in the United States occurred in 1988. In criminal investigations, DNA fingerprints derived from evidence collected at the crime scene are compared to the DNA fingerprints of suspects. Generally, courts have accepted the reliability of DNA testing and admitted DNA test results into evidence. However, DNA fingerprinting is controversial in a number of areas： the accuracy of the

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results, the cost of testing, and the possible misuse of the technique.

The accuracy of DNA fingerprinting has been challenged for several reasons. First, because DNA segments rather than complete DNA strands are \"fingerprinted\" ； a DNA fingerprint may not be unique ； large-scale research to confirm the uniqueness of DNA fingerprinting test results has not been conducted. In addition，DNA fingerprinting is often done in private laboratories that may not follow uniform testing standards and quality controls. Also, since human beings must interpret the test, human error could lead to false results.DNA fingerprinting is expensive. Suspects who are unable to provide their own DNA to experts may not be able to successfully defend themselves against charges based on DNA evidence.

Widespread use of DNA testing for identification purposes may lead to the establishment of a DNA fingerprint database.

参考生词：：

fingerprinting /'firjge.pnntir)/ n.指纹法，指纹术

genetic /d3inetik/ adj.遗传的

nucleus /'njuklis/ (复数 nuclei) n.核，中心

mammal /'maemol/ n.哺乳动物

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chromosome /'krumosoum/ n.染色体

identification /aidentifi'keijsn/ n.识别；鉴定，证明

fingerprint /'figoprint/ n.指纹

saliva /so'laivQ/ n.唾液

segment /'segment/ vt.分割，分裂；n.切片，部分

enzyme /'enzaim/ n,酶

suspect /ss'spekt/ n.嫌疑犯

controversial /ikDntro'vaiJsl/ adj.有争议的

uniform /'juinifoim/ adj. 一致的，相同的

注释：

1. In mammals the strands of DNA are grouped into structures chromosomes.

哺乳动物的DNA线被组合为称作染色体的各种结构。

2. With the exception of identical siblings (as in identical twins)：

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called

生物姊妹体除外（如完全相同的双胞胎）

3. DNA fingerprinting is sometimes called DNA typing. DNA指纹检查法有时也DNA 印记法。

4. The first criminal conviction based on DNA evidence：基于 DNA 提供证据的首例定罪。

阅读任务：

Task 1：Read the passage quickly and then summarize the main idea for each paragraph.

Para 1 __________ of DNA

Para 2 _______ to obtain a DNA sample.

Para 3 legal _________ of the DNA fingerprinting

Para 4 ________to be done about DNA fingerprinting.

Para 5 ________of a DNA fingerprint database.

Task 2：Translation

1.The segments are marked with probes and exposed on X-ray film，where

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they form a pattern of black bars — the DNA fingerprint.

2.Originally used to detect the presence of genetic diseases，it soon came to be used in criminal investigations and legal affairs.

Task 3：Discussion

What aspects is the DNAfingerprinting used for? Do you think it is important in our life?

如果你对DNA知识很感兴趣，请你课后查阅更多有关材料。

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