Chapter 19 - Viruses

Question 1

What are viruses

Answer 1

Genetic information packaged in a protein coat, infectious particles

Question 2

Are viruses alive?

Answer 2

NO- simplest unit of life is the cell and viruses are smaller than cells.

YES- viruses evolve as their genome mutates. New strands of viruses can emerge, they can replicate and reproduce.
To replicate : need a host cell

Question 3

What experiment showed something smaller than a bacterium existed?

Answer 3

Tobacco mosaic disease in plants

Question 4

What is a capsid?

Answer 4

Protein shell that encloses the viral genome

Question 5

Genome of a virus is…

Answer 5

DNA or RNA (ss or ds)

Question 6

Various shapes of capsids:

Answer 6

• rod shaped
• polyhedral
• more complex (T4)

Question 7

What are capsids built from?

Answer 7

Capsomeres

Question 8

What are the bacterial défenses against phages?

Answer 8

• restriction enzymes

- CRISP-Cas system

Question 9

Example of a temperate phage

Answer 9

Phage lambda

Question 10

Which phage undergoes lytic cycle only?

Answer 10

Virulent phage (T4)

Question 11

Which phage undergoes lysogenic cycle and lytic cycle?

Answer 11

Temperate phage

Question 12

What is the role of Reverse transcriptase

Answer 12

Catalyses the synthesis of a DNA strand complementary to the viral RNA

Question 13

What is effective to treat viral diseases in animals?

Answer 13

Vaccines

Question 14

What are other infectious agents? (7)

Answer 14

Prions
Viroids 
Viruses 
Bacteria 
Protists
Fungi 
Parasites

Question 15

___ = general outbreak of a disease

Answer 15

Epidemic

Question 16

___ = global epidemic

Answer 16

Pandemic