Task7. Read and translate the text about microorganisms.

Bacteria. Bacteria are single-celled prokaryotic eubacteria. Most bacteria can be grouped by form into four general categories: spheroid, rod, curved rod or spiral, and filamentous. Spherical bacteria are known as cocci (singular, coccus). The rod-shaped bacteria are known as bacilli (singular, bacillus). Escherichia coli is a common organism found in human feces. Curved rod-shaped bacteria are known as vibrios. Spiral bacteria are known as spirilla (singular, spirillum).

Fungi. Fungi are aerobic, multicellular, nonphotosynthetic, chemoheterotrophic, eukaryotic protists. Most fungi are saprophytes, obtaining their food from dead organic matter. Along with bacteria, fungi are the principal organisms responsible for the decomposition of carbon in the biosphere. Ecologically, fungi have two advantages over bacteria. They can grow in low-moisture areas and they can grow in low pH environments. Without the presence of fungi to break down organic material, the cycle would soon cease to exist and organic matter would start to accumulate.

Algae. Algae can be a great nuisance in surface waters because, when conditions are right, they will rapidly reproduce and cover streams, lakes, and reservoirs in large floating colonies called blooms. Algal blooms are usually characteristic of what is called an eutrophic lake, or a lake with a high content of the compounds needed for biological growth.

Protozoa. Protozoa are single-celled eukaryotic microorganisms without cell walls. The majority of protozoa are aerobic or facultatively anaerobic chemoheterotrops, although some anaerobic types are known. Protozoa feed on bacteria and other microscopic microorganisms and they maintain a natural balance among the different groups of microorganisms. A number of protozoa are also pathogenic.

Viruses. Viruses are obligate parasitic particles consisting of a strand of genetic material deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) with a protein coat. Viruses do not have the ability to synthesize new compounds. Instead they invade the living (host) cell where the viral genetic material redirects cell activities to the production of new viral particles at the expense of the host cell. When an infected cell dies, large numbers of viruses are released to infect other cells.

Task8. Answer the following questions.

1. How many general categories can most bacteria be grouped into?

2. What are saprophytes?

3. What advantages do fungi have over bacteria?

4. Why can algae be a great nuisance in surface waters?

5. How do protozoa maintain a natural balance among the different groups of microorganisms?

6. Do viruses have the ability to synthesize new compounds?

Task9. Are the sentences true or false? Explain why.

1. Most bacteria can be grouped by form into three general categories.

2. Most fungi are saprophytes, obtaining their food from living matter.

3. Algal blooms are usually characteristic of what is called an eutrophic lake.

4. Protozoa are single-celled eukaryotic microorganisms with cell walls.

5. Viruses have the ability to synthesize new compounds.

6. When an infected cell dies, large numbers of viruses are released to infect other cells.

Task10. Prove that microorganisms are of various kinds, shapes and sizes.

Task11. Prove that microorganisms are of value in nature as well as pathogenic.

Task 12. Translate the following word combinations into English, transcribe and memorize them.

быть видимым невооруженным глазом

отдельная наука

разнообразные организмы

открытие микробов

изучение строения и функций микроорганизмов

рассматривать как отдельную группу

иметь ценность

быть похожим на растение, животное

быть пригодным к чему-либо

происходить от

уладить дело

лабораторные опыты

болезнетворные микроорганизмы

одноклеточные эубактерии

отвечать за что-либо

среда с пониженным содержанием pH

клеточная стенка

синтезировать новые компоненты

GRAMMAR SECTION

Task1. Insert articles and explain their use.

1. … word microbe was coined in … latter quarter of … 19th century.

2. Then … microbiology developed into … separate science.

3. … biochemists, … geneticists, … cytologists, and … molecular biologists have discovered … value of microbes.

4. … early Greeks believed that …living things could originate from … nonliving matter.

5. Robert Koch, … German physician, defined … procedure for proving that … specific organism causes … specific disease.

6. … most bacteria can be grouped by … form into … four general categories.

7. Algae can be … great nuisance in … surface waters.

8. Viruses do not have … ability to synthesize … new compounds.

Task2. These are the answers. Make up questions.

1. The identification of microorganisms and the study of their structure and function.

2. Robert Koch, a German physician.

3. A lake with a high content of the compounds needed for biological growth.

4. On bacteria and other microscopic microorganisms.

5. When an infected cell dies.

Task3. Fill in the necessary prepositions.

1. The discovery that some living forms were invisible … the naked eye was a dramatic one … man's history.

2. Microorganisms are … incalculable value … nature.

3. Microbiology can be subdivided … theoretical, or pure, microbiology, and practical, or applied, microbiology.

4. The foundation … microbiology was securely laid … the period … about 1880 … 1900.

5. … with bacteria, fungi are the principal organisms responsible … the decomposition … carbon … the biosphere.

6. Protozoa are single-celled eukaryotic microorganisms … cell walls.

Task4. Make these sentences interrogative.

1. Microbiology encompasses the study of bacteria, rickettsiae, small fungi (yeasts and moulds), algae, and protozoans.

2. All microbiologists of the early 20th century were influenced by works of Koch.

3. Aristotle held that animals could arise spontaneously from other unlike organisms or from soil.

4. Louis Pasteur proved in a series experiments that only pre-existing microbes could give rise to other microbes.

5. The rod-shaped bacteria are known as bacilli.

6. Viruses do not have the ability to synthesize new compounds.

Task5. Convert these ideas into sentences containing Complex Subject.

1. We know that viruses are obligate parasitic particles consisting of DNA or RNA with a protein coat.

2. Scientists are sure that the viral genetic material redirects cell activities to the production of new viral particles at the expense of the host cell.

3. Specialists consider that microorganisms are no longer the exclusive concern of microbiologists.

4. Our teacher said that since the 1940s, microbiology has experienced an extremely productive period, during which many disease-causing microbes have been identified and methods to control them have been developed.

5. Laboratory assistants think that microorganisms are relatively easy to maintain and handle under laboratory conditions.