Viruses

Question 1

What is a virus?

Answer 1

A core of nucleic acid (either DNA or RNA) and a protein coat or capsid

Question 2

Viruses are not?

Answer 2

Living organisms, they have no cellular structure and rely on a host cell to reproduce

Question 3

Viruses are considered what type of parasite?

Answer 3

Obligate Intracellular parasites

Question 4

What are the two types of virus structure?

Answer 4

Naked or enveloped

Question 5

What is the size range of viruses?

Answer 5

10 - 150 nanometers, very small

Question 6

How do you see a virus?

Answer 6

Using an electron microscope

Question 7

Viruses can infect?

Answer 7

Both eukaryotes and prokaryotes (bacteria)

Question 8

Viruses that infect bacteria are called?

Answer 8

Bacteriophages or phages

Question 9

How do phages infect bacteria?

Answer 9

They use their end plates, tail fibres and spikes to attach to bacteria before injecting their DNA into the host cell

Question 10

Virulent phages?

Answer 10

Lyse (break through the cell wall) host cells after producing new phages

Question 11

Temperate phages?

Answer 11

Do not lyse the host cell

Question 12

What are the 4 lifecycle stages of a virus?

Answer 12

• attachment
• penetration and uncoating
• synthesis of nucleic acids
• protein synthesis

Question 13

What can’t viruses be grown on?

Answer 13

Agar, as they need cells to grow

Question 14

What is the best way to test a virus?

Answer 14

Viral PCR or RTPCR

Question 15

What kills a virus?

Answer 15

• UV light
• bleach
• antiviral drugs (however these only block the virus getting in or out of the cell, doesn’t actually kill it)

Question 16

Viral diseases include?

Answer 16

Measles, heroes simplex, viral haemoragic fever (Ebola)