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12.03.2020 01:10 •  Английский язык

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

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5. менее вирулентный

6. острый

7. споры

8. перепады температуры

9. более благоприятные условия

10. разрушение

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