Chapter 6: Introduction to Viruses and Prions

Question 1

All viruses have a general structure called?

Answer 1

Capsid

Question 2

What is a capsid?

Answer 2

Protein coats that enclose and protects their nuclei acid

Question 3

The capsid together with the nucleic acid is called?

Answer 3

Nucleocapsid

Question 4

Some viruses have an external covering that is made up of phospholipid bilateral and its called?

Answer 4

Envelope

Question 5

Viruses lacking an envelope are called?

Answer 5

Naked

Question 6

What are the two distinct capsid types?

Answer 6

1. Helical

2. Icosahedral

Question 7

When are viral envelope acquired?

Answer 7

When the virus leaves the host cell- taken from the host cell membrane.

Question 8

What are spikes?

Answer 8

Exposed proteins on the outside of the envelope

Question 9

Function of spikes

Answer 9

Essential for attachment of the virus to the host

Question 10

Are spikes considered a virulence factor?

Answer 10

Yes, because viruses such as H1N1 can attach to the lower respiratory tract and cause pneumonia

Question 11

Function of the Capsid

Answer 11

Protects the nucleic acid when the virus is outside of the host cell

Question 12

Function of envelope

Answer 12

Helps virus bind to a cell surface and assist in penetration of the viral DNA or RNA into suitable host cells

Question 13

An example of a complex virus (atypical viruses)

Answer 13

Poxviruses lack a typical capsid and are covered by a layer of lipoprotein

Question 14

What are lipoproteins?

Answer 14

Surface proteins that you can find in gram (-) bacteria

Question 15

What type of virus has a polyhedral nucleocapsid along with a helical tail and attachment fibers?

Answer 15

Bacteriophages

Question 16

The viral genome consist of?

Answer 16

• DNA or RNA, but NEVER both.

- Genes necessary to invade host cell and redirect cell activity to make new viruses.

Question 17

Steps of viral replication

Answer 17

Adsorption 
Penetration 
Uncoating 
Synthesis 
Assembly 
Release

Question 18

Adsorption

Answer 18

Binding of virus to specific molecules on the host cells

Question 19

Penetration

Answer 19

Genome enters the host cell

Question 20

Uncoating

Answer 20

The viral nucleic acid is released from the capsid

Question 21

Synthesis

Answer 21

Viral components are produced

Question 22

Assembly

Answer 22

New viral particles are constructed

Question 23

Release

Answer 23

Assembled viruses are released by budding (exocytosis) or cell lysis

Question 24

Penetration of the virus can occur through?

Answer 24

Endocytosis and fusion

Question 25

The release of the virus takes place through 2 major ways

Answer 25

1. Budding (exocytosis)

2. Lysis

Question 26

The damage a virus can cause to the host cells is called?

Answer 26

Cytopathic effects

Question 27

Persistent infections

Answer 27

Cells harbor the virus and is not immediately lysed

Question 28

What are prions?

Answer 28

Infectious proteins

Question 29

Prions cause?

Answer 29

Transmissible spongiform encephalopathies-fatal neurodegenerative disease.

Question 30

Example of chronic latent state viruses

Answer 30

• measles viruses - remain in brain cells for many years
• herpes simplex virus- cold sores and genital herpes
• herpes zoster virus- chicken pox and shingles

Question 31

What’s an obligate intracellular parasites?

Answer 31

Virus