Bacteria: their Construction

Bacteria are very small single-celled organisms (microorganisms) that exist in enormous numbers almost everywhere. They live in soil, water, air, and in living and dead animals and plants. A gram of soil can contain up to a thousand million bacteria, and there may be hundreds of thousands in a single drop of milk.

Bacteria differ from each other mainly in where and on what they live, and in the shape of their single cells. There are the spherical coccus types such as Staphylococcus and Streptococcus, which often occur in chains or masses, and the rod-shaped bacillus type such as Mycobacterium, which causes tuberculosis. Other disease-causing bacteria are Eberthella typhi (typhoid), and Vibrio cholerae (cholera). The type of bacterium which forms a coil or spiral is Spirillum.

Although bacteria cells are more complicated than viruses they are still very simple. Their structure has been worked out with optical microscopes which magnify by one hundred thousand times. All bacteria have a tough outer cell wall so their food must be soluble before it can be absorbed into the cell. In some bacteria there is a protecting layer of jelly enclosing the cell wall, and also one or more minute fibres (flagella) used for swimming. Inside the cell there is a coil of DNA and other chemical substances, but there is no definite nucleus or any of the other structures found in plant and animal cells.

Bacteria usually reproduce by simply splitting in two. When temperature conditions are favourable, about 37°C for most bacteria, they can divide about оncе every 30 minutes. In theory, one bacterium could form about 140 000 000 000 000 bacteria at the end of 24 hours. In fact, this does not happen because the supply of food soon runs out, poisonous wastes accumulate, and after a time no more bacteria can survive. Although most bacteria reproduce by dividing in two, some bacteria can reproduce sexually, during which the contents of one bacterium flow into another.

Bacteria are very tough. Different kinds can live in almost every environment, from hot springs to arctic frost. Many can form a type of spore under certain conditions. A spore is capsule inside which a bacterium can survive for years of drying out, intense heat or disinfectant. Few of disease bacteria can make spores.

CRAMMAR EXERCISES

PRACTICE MODALS

Ex. 1. Supply the necessary modal verbs.

1. I was very tired last night but I (не мог спать).

2. I had forgotten to bring my camera so I (не смог сделать) any photographs.

3. It was a great party last night you (следовало прийти).

4. Tom is not at work today. He (возможно болен).

5. You (не надо было спрашивать) him about it.

6. It’s a fantastic film. You (должен посмотреть) it.

7. I think you (следует купить) this dress.

8. Peter (должен был заплатить) a parking fine yesterday.

9. That restaurant (не может быть) very good. It’s always empty.

10. This is a valuable book. You (не должен потерять) it.

11. You have been travelling all day. You (должно быть) very tired.

12. I’d like to read Ann’s letter. The only problem is I (не могу найти) my glasses.

13. You (не должен помогать) him with his homework. It’s important that he does it himself.

14. I just want a general idea of the story so I (не нужно читать) all the book.

15. Why did you wash that suit? It was not dirty, you (не надо было стирать) it.

16. I don’t think you (следует смотреть) TV so much.

17. We (пришлось идти пешком) home last night. There were no buses.

18. I don’t want the children play in this room. They (могут разбить) something.

19. I am sorry that I didn’t take your advice I (следовало отправить) this letter a week ago.

20. Our teacher says that we (сможем говорить) English fluently in a few months.

21. Paul doesn’t like his new job. Sometimes he (вынужден) work at weekends.

22. This restaurant (должно быть) very good. It’s always full of people.

 

Ex. 2. Translate into Russian.

1. Water has to be thoroughly analysed during the epidemics.

2. Account has to be taken of the elastic properties of the body.

3. The lamprey must have existed at an early period.

4. Attention was to be paid to the climatic conditions.

5. This species cannot have emigrated from the North by two different routes.

6. Care is to be taken not to use methods of growing tissues on the surface of agar.

7. We know that previous to mutation there must have been a normal gene in place of the mutant gene.

8. The majority of the plant names have been taken straight from the chemical literature and taxonomists are bound to find some difficulty in interpretation.

9. Most species comprised in group 3 may have a very complicated origin.

10. It is to be regretted that the deserved attention was not given to their results.

11. It is to be emphasized that some acids are found in very few species.

12. It is to be noted that the aim was to be demonstrated the production of cells.

 

Ex. 3. Choose and use the appropriate modal verb from given in brackets.

1. These cells (need, can must, to have to be easily found in the roots as well as in the stem of that plant.

2. This plant (must, can, should) grow under such conditions rather well.

3. The roots of this plant (must, can, may, need) be used for human food.

4. Every student (may, can, should) know the difference between the leaves of oak and birch.

5. Such plants (need, must, should) have been cultivated by man long ago.

6. When water (must, may, to be (to), need) to be used for drinking it is necessary that microbes which it (to be (to), to have (to), may) contain (should, must, may) be killed.

7. You will (may, to have (to), to be (to), must) to study the characteristics of both plants as there (may, to be (to), must, can) be a considerable difference between them.

8. One (can, ought to, may, to have (to), should, must) to remember that this reaction is often followed by an explosion.

 

Ex. 4. Translate the sentences paying attention to Modals.

1. A great series of chemical changes has to occur before food becomes protoplasm.

2. These plant parts may have been found on and below the soil surface.

3. This list could be extended a long way.

4. Living protoplasm must always be thought of as a system in dynamic equilibrium.

5. Different techniques have to be used with microorganisms.

6. Hybrids may show characteristics of both parents.

7. The development of this disease must have been considerable favoured by high moisture conditions.

 

PRACTICE SUBSTITUTE WORDS

Ex. 5. Translate into Russian and pay attention to the substitute word “One”.

A.

1. One should take the precautions mentioned. 2. One believes that the procedure described above will simplify the experiment. 3. One may well ask why the two sheets of paper fly apart. 4. One is to make a lot of experiments to make sure that his observation is adequate. 5. When making experiments of this kind one is faced with still another difficulty. 6. One cannot fail to observe that the advance in technique grows more rapid. 7. Instead of numbers one might use symbols for numbers - algebra instead of arithmetic. 8. One may well ask why the numbers b and a are not identical, since they arise from much the same kind of process. 9. If one wishes to know whether or not a certain compound is present, one simply looks for a peak from that compound which would be expected in an otherwise clear region of the spectrum. 10. To know how a plant grows one should study the structure of the plant. 11. One can prevent the evaporation of moisture by means of the method which will check further loss of water. 12. One can find any book on botany in that library. 13. This is a very long distance if one takes into consideration their small size. 14. One must distinguish between processes due to the effect of biological clocks and the biochemical mechanisms of the clocks themselves. 15. By regulating the alternation of light and darkness, one can obtain three generations of sheep in two years. 16. When one says that a vessel is empty, it is not really true for the vessel is full of air. 17. One can improve the structure of the soil by proper treatment. 18. One should not forget that temperature plays an especially important role at the time of developing the root system. 19. One must always be careful when operating this machine. 20. To understand what laser is one has to understand how light is generated.

B.

1. It takes one much time to make all the necessary calculations. 2. The evidence provided by the author makes one believe that his hypothesis rests on sound foundation. 3. The figures presented involve one in the problems of modern statistics. 4. The computer allows one to make calculations in a short time. 5. Fast molecules do not diffuse through the rest as fast as their speed would lead one to expect. 6. His method permits one to get good results. 7. This led one to regard this problem as very complex.

Ex. 6. Translate into Russian and a pay attention to the substitute word “that/those”.

1. The electron temperature is much greater than that of the gas as a whole. 2. Unlike molecules can be determined by methods like those used earlier for like molecules. 3. The diameter of Neptunium is four times greater than that of the Earth. 4. The atomic weight of sulphur is twice as large as that of oxygen. 5. Suppose that the total volume of the gas is k times that of the molecule. 6. Molecules moving from hot regions to cool carry more energy than those moving in the reverse direction. 7. The tесhniquе used has some advantages over that suggested bу Раlm. 8. Тhе resu1ts are in good agreement with those calculated from the mobility data of Green. 9. Ву comparing actual strength of diffusion with that to bе expected if the molecules were elastic spheres, the value of s саn bе found. 10. Carbon dioxide cannot support life, its properties being different from those of the oxygen which it contains. 11. There are many kinds of potential energy besides that due to the force of gravity. 12. Two other very suitable temperatures are always generally available, those of melting ice and of boiling water - the former, constant under all conditions, the latter depending on the atmospheric pressure. 13. Molecules of light gases move quicker than those of denser gases. 14. There is a great difference between the functions of the leaves and those of the roots. 15. The soil of the South contains usually less moisture than that of the North. 16. Outdoor planting differs from that under glass in that the seed is not always soaked before planting. 17. The reproductive and life cycle of ferns is similar to that of the vascular plants just described. 18. Brown and Steward found that although the production of infective particles was inhibited, infectious RNA could be demonstrated at a level approaching that of control infected cells. 19. The mixture is identical to that mentioned above. 20. The minimum temperature for germination of the seed is much higher than that required for the general crop plants.

Ex. 7. Translate into Russian and pay attention to the substitute word “this/these”.

1. Тhе elements of the Periodic Group IA are called the alkali metals. Тhеsе are alike in having а single electron оn the outermost shеll. 2. The chief use of diffusion and thermal diffusion results is to determine the forces between unlike molecules. These can also be determined by methods like those used earlier for like molecules. 3. The speed of fast molecules means that they slip past the molecules which they meet without these having time to deflect them in their course. 4. If a gas molecule imparts energy to a wall molecule, this passes it on to other wall molecules. 5. We keep the ice-cream machine in the spare room. This is mainly used by the children. 6. Most American families are traditional. These comprise a father, mother, and one or more children. 7. Teenagers want independence. These feel that working parents are a benefit. 8. What does the word “politics” mean? This comes from the Greek word “police”, meaning the state or community as a whole.

 

UNIT IV

GRAMMAR. VERBALS. TOPICS. GREAT BRITAIN. LONDON. MY FUTURE PROFESSION. READING. ALGAE. ALGAE: THE SIMPLEST GREEN PLANTS.

The United Kingdom

 

The United Kingdom of Great Britain and Northern Ireland is situated on the British Isles comprising 2 large islands, Great Britain and Ireland, and a number of smaller islands washed by the North sea, the Irish sea, the English Channel and the Atlantic Ocean. Its territory is about 244,000 square kilometers; the population is about 57 million people.

When we speak about the U.K. we actually speak about 4 countries united into one state: England, Scotland, Wales and Northern Ireland. Each of these countries has its own language, its capital, its government. The capital of Scotland is Edinburgh, the capital of Wales is Cardiff, the capital of Northern Ireland is Belfast, the capital of England is London. London is the capital of the United Kingdom as well. English is the official language but a lot of people know more than one language: Welsh, Gaelic, Irish.

The surface of England and Ireland in rather flat, the highlands are in Scotland and most of Wales. The highest mountain in Scotland is Ben Nevis (1,343m high) and the highest mountain in Wales is Snowdon (1,085m high). The main rivers are the Severn, the Clyde, the Thames.

The climate is moderate and mild due to the influence of the warm waters of the Gulf Stream. There is a lot of rain in autumn and winter.

The U.K. is a highly developed industrial state. Britain is a major supplier of machinery, aerospace products, chemicals, electric equipment and a growing oil exporter. Nowadays an important part of foreign trade is so called “invisible” export: insurance, aviation, scientific and technical expertise, tourism, financial services. The biggest industrial centres are London, Glasgow, Liverpool, Sheffield, Birmingham, Manchester.

The United Kingdom is a parliamentary monarchy. Her Majesty Queen Elizabeth II (the second) is considered to be the head of the state, with a largely ceremonial role.

The legislative power belongs to the Parliament which consists of two Houses. The House of Lords is composed of hereditary, life and spiritual peers and peeresses. The members of the House of Commons are elected by the people. The executive power is exercised by the Prime Minister and his Cabinet.

There are three main political parties in the U.K.: the Labour, the Conservative (the Tories) and the Liberal-Democratic Parties. The Labour Party with David Cameron at the head is the ruling party nowadays. There is no written constitution in the U.K., only precedents and traditions.

The inhabitants of the U.K. are famous for their customs and traditions.

British people are naturally polite: they are never tired of saying “Thank you” and “I’m sorry”.

They are generally disciplined; they never talk aloud in the street; they never show their emotions even in tragic situations; they seem to remain good-tempered and cheerful under difficulties.

The most famous educational centres are Oxford and Cambridge universities. They are considered to be the intellectual centres of Europe.

 

Vocabulary

island – остров

surface – поверхность

high – высокий

highland – высокогорье

language – язык

moderate – умеренный

mild – мягкий

state – государство

major supplier – главный поставщик

electric equipment – оборудование; оснащение

foreign trade – зарубежная торговля

invisible – невидимый

insurance – страхование

aviation expertise – авиационная экспертиза

scientific and technical expertise – научно-техническая экспертиза

financial services – финансовые услуги

Her Majesty – Ее Величество (титул)

largely – главным образом

legislative power – законодательная власть

executive power – исполнительная власть

hereditary peers – наследственные пэры

life peers – пожизненные пэры

spiritual peers – епископы – члены парламента

the House of Lords – палата лордов

the House of Commons – палата общин

the Labour Party – лейбористская партия

the Conservative Party – консервативная партия

ruling party – правящая партия

inhabitant – житель

custom – обычай, привычка

polite – вежливый

aloud – громкий

remain – оставаться

good-tempered – уравновешенный; добродушный

cheerful – добрый, веселый

 

Vocabulary Notes

The United Kingdom of Great Britain and Northern Ireland – Соединенное Королевство Великобритании и Северной Ирландии

England – Англия

Scotland – Шотландия

Wales – Уэльс

the Northern Ireland – Северная Ирландия

the North Sea – Северное море

the Irish Sea – Ирландское море

the English Channel – принятое в Соединенном Королевстве название пролива Ла-Манш

the Atlantic Ocean – Атлантический океан

the Gulf Stream – течение Гольфстрим

the British Isles – Британские острова

Answer the questions:

1. Where is the U.K. situated?

2. What parts does the U.K. consist of?

3. What are the British Isles washed by?

4. What is the territory and the population of the country?

5. What city is the capital of the U.K.?

6. What language is official in the U.K.?

7. What do you know about the surface of the country?

8. Are there any high mountains and long rivers in the U.K.?

9. Why is the climate moderate and mild?

10. Is the U.K. a highly developed industrial country?

11. What do the British people produce?

12. What is an important part of foreign trade?

13. The U.K. is a parliamentary monarchy, isn’t it?

14. Do you know the name of the Queen of the U.K.?

15. What does the legislative power belong to?

16. The members of the House of Commons are elected by the population, aren’t they?

17. How many parliamentary political parties are there in the U.K.?

18. What are the inhabitants of the U.K. famous for?

19. What can you say about British character?

I. Make sentences

1. by the Atlantic Ocean, the British Isles, the Irish Sea, are washed, the North Sea

2. the territory, occupies, the U.K., 244,000 square kilometers, of about

3. in the U.K., constitution, no, there is, written

4. naturally, are, polite, British people

5. Oxford, are considered, Cambridge, the intellectual centres, to be, of Europe, and.