Questions to think about.

a. Describe viruses. Are they considered living?

b. What might account for the origin of viruses?

c. How do viruses increase in number? Describe the different mechanisms.

d. What are five diseases affecting humans that are caused by viruses?

e. Describe similarities and differences between viruses and subviruses.

3. Think of 5-7 statements that would contradict the contents of the text.

LANGUAGE FOCUS

1. Match the words that are: a) similar and b) opposite in meaning:

a)	b)
lysing	to make	terminally	useless
to promote	way	inside	inability
conventional	dissolving	normally	continuously
mode	structure	beneficial	inner
to induce	regular, normal	capacity	abnormally
machinery	to contribute	outer	outside

2. Form the derivatives of the words given in the table (where possible):

Noun	Verb	Adjective
	to interfere
	to revise
virus
infection
		befeficial
	to succeed
		sore
theory
	to elucidate
	to transfer

3. Define the following terms:

virus	prions	retroviruses
rhinovirus - ["raInqV'vaI(q)rqs]	influenza viruses - ["InflV'enzq] ['vaI(q)rqsi:z]	bacteriophage - [bxk'tI(q)rIqfeIdZ]
subvirus	AIDS	viral capsid

4. Match the first half of a sentence in column A with the appropriate second half in column B:

A	B
1. Viruses are from 10 to 100 times smaller	a) than to one another.
2. Viruses contain nucleic acids	b) which would explain their small and uncertain molecular weights.
3. Viruses are more closely related to their hosts	c) than the typical bacterium.
4. The mode of prion reproduction might involve fracture and continued growth,	d) that would identify it as living.
5. A virus is inert, incapable of reproduction, or of any metabolic functions	e) which are enclosed in a protective coat of protein.

5. Put the parts of the sentences in the right order:

a. Not, viruses, metabolize, do, cells, unlike, living.

b. Cell, within, are, the, host, virus, particles, the, assembled.

c. Known, the, virus, fastest, virus, mutating, the, influenza, is.

d. That, any, acids, contain, nucleic, there, no, is, evidence, prions.

e. Viruses, be, prions, actually, may, conventional.

f. Are, the, subviruses, infectious, smallest, agents, termed.

FOLLOW-UP ACTIVITIES

1. Prepare a dialogue with your partner discussing:

a. Viruses.

b. Subviruses.

c. Similarities between viruses and subviruses.

d. Differences between viruses and subviruses.

2. Sum up what you have learned about viruses and subviruses and prepare a report about them.

UNIT 2

MONERA

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