Viruses and bacteriophage

Question 1

How are virus classed?

Answer 1

Baltimore method - based on mode of replication and genome type

Question 2

How many groups of virus are there?

Answer 2

7 types

Question 3

Describe I virus:

Answer 3

double stranded DNA transcribed to form a positive mRNA

Question 4

Describe II virus:

Answer 4

Single stranded DNA synthesised of other strand to double stranded DNA intermediate to be transcribed to form mRNA

Question 5

Describe III virus:

Answer 5

Double stranded RNA transcribed of minus strand to mRNA

Question 6

Describe IV virus:

Answer 6

Single stranded RNA directly used as mRNA

Question 7

Describe V virus:

Answer 7

Minus single stranded RNA transcribed to mRNA

Question 8

Describe VI virus:

Answer 8

Single stranded RNA retrovirus reverse transcribed to double stranded DNA intermediate where transcribed to mRNA

Question 9

What is an alternative classification of virus?

Answer 9

International Committee on Taxonomy of Viruses

Question 10

Why are virus not in the tree of life?

Answer 10

Non-living entities

Question 11

Out of bacteria, archaea and eukarya which do virus infect?

Answer 11

All of them

Question 12

What are virophage?

Answer 12

Virus which infect the mimivirus

Question 13

What do virus do?

Answer 13

Utilise host proteins upon infection for their propagation

Question 14

How do you count viruses in the lab?

Answer 14

• Pour mixture (molto top agar, bacterial cells, and diluted phage suspension) onto solidified nutrient agar plate
• Incubate
• Count phage plaques on lawn of host cells