Viruses ✅

Question 1

What are the most common cause of human infection?

Answer 1

Viruses

Question 2

How big are viruses?

Answer 2

20-300nm

Question 3

Can viruses be visualised with a light microscope?

Answer 3

No

Question 4

What are viruses dependent on?

Answer 4

Host cells

Question 5

Why are viruses dependent on cells?

Answer 5

They are unable to synthesise their own enegy or proteins, and so are dependent on the host cells to replicate it

Question 6

What is a single virus particle known as?

Answer 6

Virion

Question 7

What can happen within hours of a virion infecting a cell?

Answer 7

It can replicate to produce hundrens of virions

Question 8

What does the rapid replication of a virion inside a cell allow?

Answer 8

Viruses to spread rapidly from cell to cell

Question 9

What do viruses consist of structurally?

Answer 9

Core of nucleic acid surrounded by the capsid

Question 10

What is the capsid?

Answer 10

A protective coating

Question 11

What is the capsid made up of?

Answer 11

Repeating subunits (capsomeres)

Question 12

What do the capsomeres of a virus determine?V

Answer 12

Viral geometric symmetry

Question 13

What are the potential forms of viral geometric symmetry?

Answer 13

• Helical

- Icosahedral

Question 14

What does the capsid mediate?

Answer 14

The attachment of the virus to specific host cell receptors

Question 15

What is the implication of the capsid mediating attachment to specific host cell receptors?

Answer 15

It defines the species and organ specificity of the virus

Question 16

What might the capsid of a virus induce in the host?

Answer 16

Host immune response

Question 17

What does the nucleic acid of a virus contain?

Answer 17

The genome

Question 18

Delete

Answer 18

Delete

Question 19

What is the capsid and the genome of a virus collectively known as?

Answer 19

The nucleocapsid

Question 20

What is the capsid of a virus sometimes covered by?

Answer 20

A lipoprotein envelope

Question 21

What does the lipoprotein envelope surrounding some viruses consist of?

Answer 21

• Lipid envelope

- Glycoprotein spikes

Question 22

What is the lipid envelope of some viruses derived from?

Answer 22

The host cell membrane

Question 23

What is the purpose of glycoprotein spikes on the lipoprotein envelope of some viruses?

Answer 23

It aids attachment to the host cell

Question 24

How do viruses with a glycoprotein envelope compare to those without?

Answer 24

Viurses WITH the envelope are LESS STABLE

Question 25

Give an example of an enveloped virus?

Answer 25

RSV

Question 26

In what way are enveloped viruses less stable than those without?

Answer 26

- Dry out rapidly in the environment | - Easily inactivated by detergent and alcohol

Question 27

Give 2 viruses without an envelope

Answer 27

- Rotavirus | - Norwalk virus

Question 28

What is the classification of viruses based on?

Answer 28

- Viral nucleic acid (DNA or RNA) - Capsid - Presence of envelope

Question 29

What features of the capsid of a virus can classification be based on?

Answer 29

- Size | - Symmetry

Question 30

What are the potenital consequences of viral infection of a host cell?

Answer 30

- Cell death - Fusion of host cells - Malignant transforation - Chronic carriage - Latent infection

Question 31

How can viruses cause cell death?

Answer 31

Inhibition of host cell protein synthesis while allowing ongoing viral protein synthesis

Question 32

What can be used to visualise cell death caused by viruses?

Answer 32

Light microscopy

Question 33

How can cell death caused by viruses be visualised by light microscopy?

Answer 33

As the cytopathic effect (CPE) in cell cultures

Question 34

What is formed by fusion of host cells caused by viruses?

Answer 34

Multinucleated giant cells

Question 35

Where can multinucleated giant cells caused by viruses be visualised?

Answer 35

In cell cultures

Question 36

Give an example of a virus that causes fusion of host cells?

Answer 36

RSV

Question 37

How can viruses lead to malignant transformation?

Answer 37

By causing unrestrained growth, prolonged survival, and morphological changes of the cell

Question 38

Give an example of a virus that can cause malignant transformation

Answer 38

HPV

Question 39

When can chronic carriage of a virus occur?

Answer 39

When there is viral replication without killing of the host cell

Question 40

What might disease result from in chronic virus carriage?

Answer 40

- Direct damage from virus itself | - Host inflammatory response against viral antigens

Question 41

When does latent viral infection occur?

Answer 41

When the virus remains within the cell but doesn’t replicate

Question 42

What group of viruses cause latent infection?

Answer 42

All herpesviruses

Question 43

What happens following primary infection with varicella zoster virus?

Answer 43

It enters a latent phase

Question 44

What does VZV cause when reactivated?

Answer 44

Shingles