Microbiology

The body provides a home for a great number of the smallest organisms – microorganisms. Most of them are harmless but some take part in dental diseases. There are three different groups of microorganisms: fungi, bacteria and viruses. They may be of different kinds, both harmless and more or less dangerous.

Bacteria are subdivided into groups according to their shape bacilli, cocci, spirochetes, spores.

Bacilli are rod – shaped bacteria. For example, lactobacillus is found in decayed teeth.

Cocci are round bacteria.

Streptococci are berry – shaped bacteria which grow in twisted chains. They are associated with different diseases. Hemolytic streptococci (called hemolytic because bacteria cause hemolysis) are responsible for such conditions as “strep” throat, tonsillitis.

Streptococci viridians (viridians means “green” and these bacteria produce a green color on the growth medium) are less virulent (poisonous) than the hemolytic form and cause infections in teeth.

Staphylococci are bacteria which grow in small clusters like grapes. One strain of staphylococcus may be found in gumboils.

There are also spiral bacteria (spirochetes) found in acute necrotizing ulcerative gingivitis.

Some bacteria can exist in the form of spores. Spores can survive extremes of temperature and live for years until conditions become more favorable again. They are highly resistant to destruction.

EXERCISES

EXERCISE 1. Укажите русские эквиваленты следующих слов и словосочетаний:

1. to provide a home;

2. both harmless and less or more dangerous;

3. to be associated with;

4. the growth medium;

5. to cause infection,

6. gumboils;

7. to survive extremes of temperature;

8. to be highly resistant to destruction.

EXERCISE 2. Найдите в тексте эквиваленты следующих слов и словосочетаний:

1. безвредный

2. более или менее опасные

3. в соответствии с формой

4. ассоциироваться

5. менее вирулентный

6. острый

7. споры

8. перепады температуры

9. более благоприятные условия

10. разрушение

EXERCISE 3. Процитируйте предложения из текста со следующими словами и словосочетаниями:

1. to provide a home

2. to take part in

3. to be subdivided into

4. to be found

5. to grow in twisted chains

6. to initiate

7. to cause infection

8. to grow in small clusters

9. to survive

10. to be highly resistant.

EXERCISE 4. Ответьте на вопросы:

1. What does a mouth provide a home for?

2. Are all bacteria harmless?

3. What groups of bacteria do you know?

4. How are bacteria subdivided?

5. What are bacilli and where are they found?

6. How do streptococci grow?

7. What do they initiate?

8. What bacteria are called staphylococci?

9. What can be found in acute necrotizing ulcerative gingivitis?

10. Can spores survive extremes of temperature?

EXERCISE 5. Закончите следующие предложения:

1. Streptococci are less virulent than …

2. Viruses are sometimes more dangerous than …

3. One strain of staphylococcus is easier found in gumboils than …

4. Spores are more resistant to destruction than …

5. Bacteria are often more dangerous than …

6. Inflammation may be more protective than …

7. Infection may be often the initial cause of the disease than …

EXERCISE 6. Переведите на английский следующие предложения:

1. Большинство бактерий безвредны, но некоторые вызывают серьезные заболевания.

2. Споры гораздо более устойчивы к неблагоприятным условиям, чем другие бактерии.

3. Они более устойчивы к разрушению, чем другие виды бактерий.

4. Этот вид бактерий такой же опасный, как и тот, который мы изучили на прошлом занятии.

5. Иногда воспаление – скорее неблагоприятная реакция, чем защитная.

EXERCISE 7. Задайте 10 вопросов по тексту.

EXERCISE 8. Перескажите текст.

PLAN OF THE RETELLING

1. I have read the … which is called…

Дата добавления: 2014-12-16