学位英语

第三篇

Genetic Engineering

Genetic engineering began when the DNA molecule(分子), the most basic unit of life, was first described in 1953 by James Watson and Francis Crick. An understanding of DNA led to the altering of normal cell reproduction. Experiments with altering human cells began in 1970. In one of the first experiments, patients were injected with a virus that would produce a life-saving enzyme, but their bodies would not accept it. In 1980 patients with a rare but fatal blood disease were injected with a purified gene that was cloned through DNA technology. Another failure.

Genetic engineering got a legal boost(激励) in 1980. The U.S. Supreme Court said that a patent could be granted on a genetically engineered "oil-eating" bacterium(细菌). This bacterium would help clean up oil spills. The ruling encouraged companies to invent new life forms, and three important medical products were quickly developed.

l Human interferon(干扰素)-- a possible solution to some cancers and viral disease. A newly engineered bacterium produced human interferon as a by-product. This new product reduced the cost of interferon.

l Human growth hormone-- for children whose bodies do not grow to normal height. An expensive growth hormone(荷尔蒙) was previously produced from human cadavers, but by changing the genetic make-up of the single-cell bacterium E. coli, and affordable growth hormone could be produced.

l Human insulin(胰岛素)-- for the treatment of diabetes. People with diabetes used to rely on a beef- or pork-based product until 1982. Now insulin can be manufactured by genetically altered bacteria.

Advances in genetic engineering have continued, though they constantly must be weighted against the safety of procedures. There is clearly much more to discover.

41. This passage is mainly about

A. the human growth hormone.

B. the effects of altering cells.

C. insulin resistance.

D. U.S. Supreme Court rulings.

42. Genetic enginerring may be defined as

A. the altering of normal cell reproduction

B. a branch of applied chemistry.

C. a procedure that holds little promise.

D. a study on life-saving enzymes.

43. According to the passage, human interferon

A. is a hormone that causes disease.

B. could be used to treat cancer.

C. is a viral disease

D. has been cured

44. In this passage, the three genetically engineered medical products are presented

A. as a process.

B. from earliest to latest.

C. in a simple list.

D.as a story.

45. In the last paragraph, the word "weighed" has the cloest meaning with

A. had great influence

B. became a burden.

C. measured accurately.

D. considered carefully.

本题分数（15）

41  B  从第一段尤其是前三句中我们可以了解到，遗传工程就是对细胞进行改造，而后面

列举的三种重要的医疗产品正是细胞改造的成果，因此B项可以概括短文的内容，其他

三个选项均不恰当。

42  A  本文介绍的是遗传工程，第一段后半部说到，对DNA的了解导致了对正常细胞繁殖

的改造，并由此进行了一些实验，可见遗传工程就是“对正常的细胞繁殖进行改造”。

43  B  第三段第一句明确说到，“人体干扰素可能解决某些癌症和病毒性疾病的问题”。

44  C  从文章的表达方式来看，可以很明显看到，这三种通过遗传工程产生的医疗产品是

以罗列的方式来介绍的，其他三个选项均不符合文章的实际内容。

45  D  在本句中，作者说“遗传工程还在继续获得进展，不过还需认真考虑它的安全性”

在这里weigh实际就是“衡量、考虑”的意思，其他三个选项均不恰当。

（责任编辑：vstara）

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