Virology 1

Question 1

Viruses are what?

Answer 1

subcellular genetic elements and obligate parasites

Question 2

Viruses are not what?

Answer 2

cells
do not self replicate on their own
motile, so they have no energy supply

Question 3

What are virions?

Answer 3

Virus particles

Question 4

What type of genome are in virions?

Answer 4

DNA or RNA, single or double stranded, linear, circular or segmented

Question 5

RNA viruses genome can have + or - sense. + sense is the same as?

Answer 5

mRNA

Question 6

The genome of a virus is packed in what?

Answer 6

protective protein coat or capsid

Question 7

The virion has an envelope made of what?

Answer 7

host cell membrane modified to contain virus proteins

Question 8

what are the 6 features of a virus?

Answer 8

Surface glycoprotein
Matrix protein
surface protein
Nucleocapsid surrounding the genome
Protein 
Envelope

Question 9

What interacts with the host cell?

Answer 9

Outermost proteins/glycoproteins

Question 10

To protect the genome from breakdown by nucleases, the capsid proteins are assembled how?

Answer 10

Symmetrically around the nucleic acid to form either an icosahedral capsid or a helical capsid

Question 11

Name 3 types of viruses with icosahedral symmetry?

Answer 11

Adeno, Herpes and papillo

Question 12

Examples of viruses with helical symmetry?

Answer 12

Influenza and mumps

Question 13

what exhibits complex symmetry??

Answer 13

Poxvirus

Question 14

what virus has multiple shelled capsids?

Answer 14

Rotaviruses

Question 15

how are viruses classified?

Answer 15

By kind of nucleic acid genome, strategy of replication and morphology of the virion

Question 16

Name some DNA viruses

Answer 16

Pox, herpes, adeno, papilla, parvo

Question 17

Name some RNA viruses

Answer 17

Influenza, mumps, rabies, AIDS, LCM, Rota, polio

Question 18

what is infectivity assay?

Answer 18

poliovirus plaques in a monolayer cell culture

Question 19

what are the 6 stages of viral replication?

Answer 19

Attachment
Penetration
Uncoating
Genome Replication
RNA Synthesis
Protein Synthesis
Assembly
Release

Sometimes protein synthesis can result back to genome replication

Question 20

How an step 2 and step 6 occur?

Answer 20

Step 2 is penetration which is either direct or by endocytosis.
Step 6 is by cell lysis, either non enveloped viruses or budding enveloped viruses.

Question 21

The two ways a virus enters a cell and what is required?

Answer 21

Virus must fuse with the plasma membrane or endocytosis. Both require interaction with a receptor on the host cell

Question 22

binding of the virus to the receptor limits what?

Answer 22

limits the cell types and species that can be infected

Question 23

Once the virus has entered the cell, the genome has to what?

Answer 23

Be uncoated and has to go to the right place in the cell for replication

Question 24

What is + DNA sense?

Answer 24

Single strand of DNA sense if an RNA version of the same sequence is translated or translatable into protein

Question 25

Describe the poliovirus replication process

Answer 25

Single stranded + RNA encodes structural and nonstructural proteins. This is then translated into a polyprotein which is autocleaved where various proteins are produced such as structural coat proteins, proteases and rna polymerase. These proteins then allow for the synthesis of new plus strands. Minus strands are also produced.

Question 26

Viral proteins end up where?

Answer 26

Envelopes of viruses traffic through the ER and Golgi and are deposited on the surface of the cell and then are glycosylated.

Question 27

How are enveloped viruses acquired?

Answer 27

By budding through host cell membranes

Question 28

what is a nucleocapsid?

Answer 28

Capsid containing viral chromosome