5. Overview of Viruses

Question 1

What neutralizes the viral particles?

Answer 1

Antibody to the viral spikes

Question 2

what is the importance of a mutating viral spike?

Answer 2

mutated spike = new spikes = human antibody can’t recognize. Also, expands the range of potential hosts a virus might infect.

Question 3

Virus consist of:

Answer 3

1. Genes (genome that is ds DNA/RNA, ss DNA/RNA

2. Capsid (protein bottle/shell)

Question 4

2 ways virus leave the host cell:

Answer 4

1. Budding

2. Lysis

Question 5

what is budding?

Answer 5

Virus leaves the host cell in a membrane bubble that stays around the capsid and forms an envelope. Envelope usually has spikes.

Question 6

What is lysis?

Answer 6

Virus triggers host cell to break open, allowing naked nucleocapsids. Spikes are integrated into capsid.

Question 7

What are the 5 outcomes/response of host cells to viral infections?

Answer 7

1. Abortive
2. Lytic
3. Chronic, non-lytic
4. latent
5. Transformation

Question 8

Abortive is….

Answer 8

When no progeny virus are produced in host cell.

Question 9

Lytic is….

Answer 9

The acute process where viral progeny are releasted by death (Lysis) of the host cell.

Question 10

Chronic, non-lytic, is…

Answer 10

when virally infected cells slowly release viral progeny without dying.

Question 11

Latent is…

Answer 11

when virus genome usually becomes integerated into the cell DNA and stays dormant. Virus can ‘re-awake’ at anytime and produce progeny.

Question 12

Transformation is…

Answer 12

when virus causes cell to proliferate uncontrollably.

Question 13

Virus capsids can be:

Answer 13

helical or icosahedral

Question 14

+ Viral DNA/RNA is “____________” whereas - DNA/RNA is “_______.”

Answer 14

+ Viral DNA/RNA is in “the same orientation as mRNA” whereas - DNA/RNA is “anti-sense.”

Question 15

Viruses are simply “_____ ________”

Answer 15

Viruses are simply “genetic instruction”

Question 16

The 2 key steps for virus to replicate and cause disease are:

Answer 16

1. Replication of their genetic material

2. Produce positive-stranded mRNA (+RNA), to replicate their protein components.

Question 17

What is the overall cycle for a virus to infect a host cell? (6 steps)

Answer 17

1. Attachment - to host cell
2. Penetration
3. Uncoat protein capsid - to expose viral genome
4. Replicate viral genome and structure
5. Assemble new virus
6. Release

Question 18

Viremia is….

Answer 18

The release of viral agent into the blood.

Question 19

Viroid is…

Answer 19

a nucleic acid polymer lacking a capsid (basically a virus without a capsid. Only infects plants)

Question 20

Prions are…

Answer 20

infectious agents that are only protein. Infects humans and animals

Question 21

Virus have “______” effect. Many infections occur with little or non obvious symptoms.

Answer 21

Virus have “iceberg” effect. Many infections occur with little or non obvious symptoms.