Chapter 2

Question 1

Define a virus.

Answer 1

infectious agents consisting of one or several molecules of DNA or RNA, usually covered by a protein coat and sometimes by a more complex envelope

Question 2

How do ordinary bacteria, Rickettsia, and viruses compare in regards to binary fission?

Answer 2

Ordinary bacteria and Rickettsia both use binary fission and viruses do not

Question 3

How do ordinary bacteria, Rickettsia, and viruses compare in regards to having both DNA and RNA?

Answer 3

Ordinary bacteria and Rickettsia have both DNA and RNA, viruses only have one or the other

Question 4

How do ordinary bacteria, Rickettsia, and viruses compare in regards to having ribosomes?

Answer 4

Ordinary bacteria and Rickettsia have ribosomes, viruses do not

Question 5

How do ordinary bacteria, Rickettsia, and viruses compare in regards to metabolizing substrates?

Answer 5

Ordinary bacteria and Rickettsia metabolize substrates and viruses do not

Question 6

How do ordinary bacteria, Rickettsia, and viruses compare in regards to sensitivity to antibiotics?

Answer 6

Ordinary bacteria and Rickettsia are both sensitive to antibiotics, you do not use antibiotics to treat viruses

Question 7

How do ordinary bacteria, Rickettsia, and viruses compare in regards to being an obligate intracellular organism?

Answer 7

ordinary bacteria are not obligate intracellular organisms, Rickettsia and viruses are

Question 8

What 3 mechanisms do viruses use to circumvent the immune system?

Answer 8

viral latency antigenic variation destruction of the immune system

Question 9

What are the 5 means that viruses employ for transmission?

Answer 9

contact, ingestion, use aerosols, insect vectors, and live cells travel from one host to another

Question 10

What are the 2 useful aspects of viruses?

Answer 10

The agents are able to transmit their nucleic acid from one host cell to another, and use the host’s enzyme apparatus to replicate by superimposing their genetic information on the metabolic machinery of the host cell

Question 11

How did viruses originate?

Answer 11

It is speculated that viruses probably arose from cellular DNA sequences that learned to wrap themselves in protective proteins that shielded them from environmental nucleases and other destructive forces.