1. What was found by a German biochemist in the late XIX

century?

2. Who suggested that DNA carries genetic information? When

did it happen?

3. What was an important foundation for the description of

DNA?

4. In what scientific institutions were researches on DNA

carried out?

5. What did the Cambridge team try to create?

6. What kind of work did King’s team carry out?

7. What did Franklin find out about DNA?

8. Why did Watson and Crick fail?

IV. Answer the questions.

1. What new information about DNA he/she has learnt from

the text?

2. Is it really important and necessary to know DNA structure?

Why?

IV. Answer the question

Can you tell what DNA is?

Variant 4

Text 4.

Cloning of an Adult Mammal.

I. Study these words. Make sure you know them.

fashion, genetic, clone, mammal, expert, egg, offspring,

to extract.

II. Read the text and do the tasks following it.

When Dr. Ian Wilmut introduced the world to the world to

the first successful clone of an adult mammal – a seven-month

old Finn-Dorset lamb named Dolly – a new frontier in science

opened wide.

When Dr. Ian Wilmut and his team from the Roslin

Institute created a lamb named Dolly, they accomplished what

many experts thought was a scientific impossibility. Unlike

offspring produced in the usual fashion, Dolly does not merely

take after her biological mother. She is a carbon copy, a

laboratory counterfeit so exact that she is in essence her

mother’s identical twin.

In 1996, Dolly became the first large animal to be cloned

from genetic material extracted from an adult cell. Scientists

Inserted a cell from a ewe’s udder into an egg from the same

animal after removing the egg’s DNA. The bioengineered

embryo was implanted in the ewe’s womb and Dolly developed

as a clone. Her birth at the Roslin Institute in Scotland was

announced in 1997 and caused an international sensation.

III. Comprehension Check.

1. Match the words with their meaning by placing the

proper letter on each blank.

_1. adult a) to look or behave like

_2. frontier b) a bag like organ of a cow, from which

milk is produced

_3. to accomplish c) a grown up female sheep

_4. to take after d) a fully grown person or animal

_5. to counterfeit e) to succeed in doing smth

_6. udder f) to copy closely in order to deceive

_7. ewe g) an organ where offspring develop

before it is born

_8. womb h) child or children

_9. offspring i) limit or border

2. What do you think

1. Where was Dolly cloned?

2. Why doesn’t Dolly take after her biological mother?

3. What cell was inserted into an egg?

IV. Answer the questions.

1. What new information about cloning have you learnt from

the text?

2. Do you think that scientists should be allowed to conduct

human and animal cloning experiments?

V. Answer the questions.

What is cloning.? Will it ever be possible to

produce exact copies of human beings?

Сам. работа 6

Variant 1

Read the text and do the tasks following it.

STRENGTH OF MATERIALS

A. Nowadays the science Materials Strength is considered to be a basic engineering discipline. The initial study of this subject was undertaken* by the great Galileo.

The research into the problems of materials strength was markedly intensified in the 19th century. This research was of great importance for the industrial development of the society. Thousands of miles of railways were laid, bridges were erected at that time. People built tunnels and ocean-going ships, they used elaborate* apparatus and digged into the earth in searching for minerals.

B. A lot of structures built centuries ago have not only survived but remained in use.Some of them had been however destroyed because of the errors made by the builders. Sometimes tragedies happened, the buildings were destroyed, machines broke down or bridges collapsed. The reason for those failures was the lack of knowledge on the part of experts: the problems of materials strength were still hidden deep in the mysteries of atomic and molecular structures of materials. That is why it was necessary for any engineer to study the processes determining stresses and deformations in structures and machines under loading conditions.

C. The study on physics of materials strength was first undertaken in the 20th century. Mankind was already entering the age of high speeds, pressures and temperatures ,the age of advanced technology and new unknown materials.

In the 1920s the top speed of an airplane was not more than 200 kilometres per hour, the load per square metre of the wing area was about 50 kilograms. The main construction material was wood. Nowadays the speed of aircraft, even passenger planes, is approaching 3,000 km per hour, with the loads as high as 600 kilograms per square metre of wing. The turbine that drives such anaircraft is not only a miracle of a design, it is also a miracle of materials strength. The given examples are sufficient to illustrate the advantages of new costruction materials.

D. Creation of new materials is of tremendous importance for the further technological development of the society.

Chemists engaged in polymer research have developed synthetic rubbers*. Tyres* made of synthetic rubbers can cover distances several times exceeding the distance from the Earth to the Moon. Having tested a new class of aluminium alloys the metallurgists produced a new durable alloy. It turned to be of great use for aircraft and rocket engineering needs. The technological problem of substantial weight reduction of apparatus was solved due to the considerable material savings.

A further development of the science Materials Strengh will ultimately result in delicate bridges, light airy buildings, small but powerful machines and airplanes capable of carrying huge loads.

* to undertake the study of - начинать изучение

* elaborate - сложный; тщательно-разработанный

* alloy - сплав

* rubber - резина, каучук

* tyre - шина

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