问答题

Biotechnology is the name that has been given to a very wide range of agricultural, industrial and medical technologies that make use of living (47)______ (e.g., plants or animals) or parts of living organisms to provide new products and services. Biotechnology’’s (48)______ lie in the ancient crafts of brewing(酿造), baking and the production of fermented(发酵) foods such as yoghurt and cheese. It was not until 1859 that the cause of both desirable and (49)______ changes in food was identified. Louis Pasteur provided a scientific understanding of these natural processes, which helped to improve the (50)______ of traditional fermentations and ensure the safe (51)______ of food and drink. Pasteur thought that living organisms were always needed to bring about the changes which occur during fermentation. Towards the end of the last century, however, it was realized that non-living extracts from cells could also cause changes that are normally associated with the activities of whole organisms. These extracts were named "enzymes" (酶). We now know that all living things produce enzymes—proteins that are (52)______ for many of the processes of life. During the 1940s, methods of growing living organisms were developed for the production of penicillin and other antibiotics used in medicine. Today this technology permits the (53)______ production of a wide range of products. These include enzymes for food and drink production processes, vitamins and other useful chemicals. In 1973, two scientists, Stanley Cohen and Herbert Boyer, managed for the first time to make very specific changes to the genetic make-up (i.e., the DNA) by means of "genetic engineering" (also called genetic modification). The techniques have since been applied to plants and animals, and in a limited way they have also been applied to humans in an attempt to (54)______ the symptoms of inherited illness. Although the term biotechnology refers to a much older and (55)______ technology than genetic engineering, the techniques of genetic engineering are of such importance that the two terms have become virtually synonymous, (56)______ in the USA. Word Bank A) reliability B) commercial C) broader D) transfer E) undesirable F) alleviate G) progress H) particularly I) reveal J) organisms K) comment L) responsible M) preservation N) origins O) genetics