Vocabulary notes

in fact - фактично

at least – принаймні, щонайменше

act as – виступати, діяти як

unlike something – на відміну від

infect with – заражати (чимось)

in addition (to) – до того ж, на додачу (до)

III. Match two halves of the sentences

Two types of vaccine to protect horses from West Nile virus are available this year. West Nile kills about one-third of unvaccinated horses that mosquitoes… Viruses, like bacterial infective agents,… Smallpox was effectively elimated as a scourge on humanity by worldwide vaccination programs. In… Virions contain at least… Not infrequently, the virus-specific T lymphocyte kills vital cells such as nerve cells (neurons), muscle cells, and liver cells, all of which carry out important functions. In… Unlike bacteria,…

…fact the chances of getting smallpox from a bad vaccine were greater than that of ever encountering the virus in nature. …addition, the death of cells results in an inflammatory response, which also can damage vital tissues. …infect with the virus, a Kansas State University scientist said. …viruses mimic the metabolic functions of their host cells. …40 proteins and lipids, as well as internal structures called lateral bodies. …act as antigens in the body and elicit formation of antibodies in an infected individual.

IV. Split the text “Viruses” into several logical parts and give titles to them

V. Think of possible questions for the following answers

1. Because viruses are not free-living organisms.

2. It’s the extracellular form of a virus;

3. These organisms are called viroids.

4. Because they do not have ribosomes.

5. The virus derives it from the host cell.

6. It performs three basic functions.

7. The reason is in the frequent changes of the viral DNA or RNA sequences.

8. Viruses can reproduce only in host cells.

9. Such viruses do not destroy the cell at once.

10. Short term diseases are referred to as acute and long-term diseases are called chronic.

VI. Say whether the following statements are true or false according to the text “Viruses”

1. Viruses lack some functions characteristics of other living organisms.

2. All viruses have RNA molecules.

3. At different stages of their development virions can transform into viroids or prions.

4. The parasitic nature of viruses is manifested in their dependence on host cells for energy and protein synthesis mechanism.

5. A virus deprived of its capsule can never penetrate into the host cell.

6. The virion capsid performs a protective function.

7. The main criteria used for viruses classification are their size and shape.

8. Viruses lack the mechanism of correcting the errors in the nucleic acid sequences.

9. The viruses are harmless for their host cell as long as the latter are not subjected to specific physical or chemical influences.

10. Medicine of the future may rely on viruses for the repair of certain genetic defects in humans.