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Flashcards in An Introduction to Viruses Deck (40)
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1

What can you say about the size of viruses?

They are very small, being only 20-400nm in diameter

2

What can you say about cells, viruses and replication?

Viruses are non-cellular so genetic elements cannot replicate independent of a host

3

What are different structures of viruses?

Icosahedral (20 faces, each in an equilateral triangle)

Helical (protein binds round DNA/RNA in a helical fashion)

Complex (neither of above)

4

What can you say about the host range of viruses?

Many viruses have a specific host range and can only infect specific host cell types

5

Can viruses be grown in a lab dish?

No, because they need a cell to act as a host

6

What are examples of icosahedral viruses?

Polio

Rhino

Adeno

7

What is an example of a helical virus?

Tobacco mosaic virus

8

What is a virus?

Genetic element that cannot replicate independently of a living (host) cell

9

What is virology?

The study of viruses

10

What is a virion?

Extracellular form of a virus

11

Where do virions exist and what do they do?

They exist outside of the host and facilitates transmission from one host cell to another

12

What do virions contain?

Nucleic acid genome surrounded by a protein coat and in some cases other layers of material

13

What are virus families classified according to?

Virion shape/symmetry

Presence/absence of envelope

Genome structure

Mode of replication

14

What do envelopes do to a virus?

Makes them much more fragile, making them easier to kill and cannot survive outside the body for a long time

15

What are examples of enveloped viruses?

Flu

HIV

Hep C

16

17

Where are lipid envelopes stolen from?

The host cell the virion came out of

18

What is the process of virus replication?

1) Replication of genomic nucleic acid

2) Virion assembly

3) Virion released from cell and attaches to another

4) Uncoats inside the other cell

5) Replication of genomic nucleic acid

19

What are different kinds of transmission?

Blood borne

Sexual

Vertical

Faecal-oral

Droplet

Airborne

Close contact

Vector borne

Zoonotic

20

What can you say about the kinds of animals viruses can infect?

Some viruses can only infect humans whereas some can infect a range of animals, leading to recombination and generation of new strains

21

What does viruses infecting many kinds of animals lead to?

Recombination and generation of new strains

22

What are the possible consequences of viral infection?

Clearance of virus (no short or long term immunity)

Chronic infection

Latent infection (virus lies dormant)

Transformation (long term infection with altered cellular gene expression)

23

What happens when viruses lie dormant?

Full virus genome is retained in the host cell but expression is restricted, but reactivation may occur

24

What are examples of viruses that can lie dormant?

Herpes simplex virus

Varicella zooster virus

25

How can viruses lead to cancer?

Modulation of cell cycle control (driving cell proliferation)

Modulation of apoptosis (prevention of programmed cell death)

Reactive oxygen species damage (causes inflammatory response which lead to cancer via oxygen species)

26

What aspects of a virus can be detected?

Whole organism

Part of organism (such as antigen or nucleic acid)

Immune response to a pathogen (such as an antibody)

27

What can the whole organism be detected by?

Microscopy

Culture

28

What is not really used anymore?

Electron microscopy and cell culture

29

Why is cell culture not practical?

Works well but has a large time lag

30

What can looking at the immune response determine?

Acute/recent infection

Prior infection/response to vaccination