1. Introduction to Microbiology

Viruses:

This type of acellular infectious agent is only known to infect plants and is a small, circular, single-stranded nucleic acid molecule.

An infectious protein is known to cause neurodegenerative diseases in humans such as Creutzfeldt-Jakob disease ('mad cow disease'). This type of acellular infectious agent is known as a _________.

Which of the following statements about acellular infectious agents is FALSE?

All of the following can be transmitted by recreational (i.e., swimming) water sources except

a. amebic dysentery.

b. cholera.

c. giardiasis.

d. hepatitis B.

e. salmonellosis.

Which of the following is not an acellular agent?

a. viroid

b. virus

c. rickettsia

d. prion

Which of the following statements is true?

a. Viruses move toward their host cells.

b. Viruses are capable of metabolism.

c. Viruses lack a cytoplasmic membrane.

d. Viruses grow in response to their environmental conditions.

A virus that is specific for a bacterial host is called a __________ .

a. phage

b. prion

c. virion

d. viroid

A naked virus __________  .

a. lacks a membranous envelope

b. has injected its DNA or RNA into a host cell

c. is devoid of capsomeres

d. is one that is unattached to a host cell

Which of the following statements is false?

a. Viruses may have circular DNA.

b. dsRNA is found in bacteria more often than in viruses.

c. Viral DNA may be linear.

d. Typically, viruses have DNA or RNA but not both.

Another name for a complete virus is ___________ .

a. virion

b. viroid

c. prion

d. capsid

Which of the following is not a criterion for specific family classification of viruses?

a. the type of nucleic acid

b. envelope structure

c. capsid type present

d. lipid composition

A clear zone of phage infection in a bacterial lawn is __________ .

a. a prophage

b. a plaque

c. naked

d. a zone of inhibition

Match each numbered term with its following description.

1. _________ uncoating

2. _________ prophage

3. _________ retrovirus

4. _________ bacteriophage

5. _________ capsid

6. _________ envelope

7. _________ virion

8. _________ provirus

9. _________ benign tumor

10. ________ cancer

A. dormant virus in a eukaryotic cell

B. a virus that infects a bacterium

C. transcribes DNA from RNA

D. protein coat of virus

E. a membrane on the outside of a virus

F. complete viral particle

G. inactive virus within bacterial cell

H. removal of capsomeres from a virion

I. invasive neoplastic cells

J. harmless neoplastic cells

Label each step in the bacteriophage replication cycle below.

a._______<IMAGE>

b._______<IMAGE>

c._______<IMAGE>

d._______<IMAGE>