ANI SCI 320 Lecture 7 : Viruses

Question 1

What are the 3 things an acellular and virion consist of?

Answer 1

1. RNA and DNA core
2. Protein coat (capsid)
3. Lipid envelope

Question 2

What type of life forms can viruses infected?

Answer 2

ALL types of life forms

Question 3

What are important consideration of virus replication?

Where do DNA viruses replicate vs RNA viruses

Answer 3

Can replicate only when within living host cell

DNA viruses replicate within the nucleus, while RNA viruses replicate within the cytoplasm

Question 4

What are the 5 components of a virus?

Answer 4

1. Virus proteins
2. Envelope from host cell
3. Nucleoprotein
4. Capsid formin virus structure
5. Nucleic acid

Question 5

What are the two systems of classification for virsues?

Answer 5

1. Hierarchical
2. The Baltimore

Question 6

What are the 3 different ways of viral entry?

Answer 6

1. Direct Penetration
2. Membrane Fusion
3. Endocytosis

Question 7

What is direct Penetration?

Answer 7

The viral capisd or genome is injected into the host cell’s cytopasm

Question 8

What is membrane fusion?

Answer 8

The cell membrane is puncture and made to further connect with the unfolding viral envelope

Question 9

What is endocytosis?

Answer 9

The host cell engulfs and takes in viral particle

Question 10

What is uncoating?

Answer 10

Stripping off the viral protein coat releasing the viral nucleic acid or genome

Question 11

How does transcription and mRNA production play into viral reproduction?

Answer 11

Virus takes advantage of host cell structures to replicate itself

Question 12

What is viral protein synthesis?

Answer 12

Virus mRNA is translated on host cell ribosomes into two types of viral protein

Question 13

What is virion assembly?

Answer 13

Newly synthesized genome and proteins are assembled to form new virus particles

Question 14

What is viral latency?

Answer 14

Ability of some viruses to remain dormant within the host cell

Question 15

What forms can the viral genome remain latent?

Answer 15

1. Episome
2. Integrated in the host chromosome

Question 16

How is latency generally maintained?

Answer 16

A few viral genes

Question 17

How is latency stopped?

Answer 17

Viral genome reactivates promoted by external stimuli

Question 18

What are the 2 options for viruses with ability for latency?

Answer 18

1. Latency
2. Lytic pathway

Question 19

What is viral shedding via budding?

Answer 19

Most effective for viruses that require an envelope

Before budding the viral receptor are placed on the host cell surface

Depletes host cell membrane and eventual host cell death

Question 20

What is viral shedding via apoptosis?

Answer 20

Forced cell suicide releases viral progeny

As apoptotic host cells are phagocytosed by macrophages, virus has the opportunity to get into macrophages o infect or to be transported to other tissues in the body

Question 21

What is viral shedding via exocytosis?

Answer 21

Used primarily by non enveloped viruses

Host cell is not destroyed

Virus progeny are enclosed in vesicles and transported to cell membrane to be released

Question 22

What is the viral pathogenesis cycle by HIV? 7 Steps

Answer 22

1. HIV fuses to the host cell surface
2. HIV RNA, reverse transcriptase, integrase and other viral proteins enter the host cell
3. Viral DNA is formed by reverse transcription
4. Viral DNA is transported across the nucleus and integrates into the host DNA
5. New viral RNA is used as genomic RNA and to make viral proteins
6. New viral RNA and proteins move to the cell surface and new immature HIV forms
7. The virus matures and when protease releases the proteins that form the mature HIV.

Question 23

A provirus is an….

Answer 23

Integrated virus