Virus Replication Strategies

Question 1

What size can virus genomes be between?

Answer 1

2kb and 2.5Mb

Question 2

What is a good example of an enveloped virus?

Answer 2

Influenza

Question 3

What does being enveloped or non-enveloped define?

Answer 3

The replication cycle

Question 4

What is a good example of a non-enveloped virus?

Answer 4

Polio

Question 5

What are non-enveloped viruses coated by?

Answer 5

A capsid only , they possess no membrane

Question 6

How do enveloped viruses get into cells?

Answer 6

Have to fuse the membrane with the membrane of a cell

Question 7

How do non-enveloped viruses get into cells?

Answer 7

Have to go into invaginate vesicle and fuses the vesicle

Question 8

What are repeating subunits of a capsid called?

Answer 8

Capsomeres

Question 9

What shapes can capsids take?

Answer 9

Helical
Icosahedral
Complex

Question 10

What is the most common shape of viruses and the least common?

Answer 10

Icosahedral is most common
Helical is rare for medically important viruses
Complex viruses - no human pathogens like this

Question 11

What can virus families be assigned based on?

Answer 11

Nucleic acid - DNA or RNA
Ss or ds genome
Positive sense or negative sense
Virion architecture

Question 12

What is class 1 Baltimore system?

Answer 12

DsDNA virus

Question 13

What is class II Baltimore classification?

Answer 13

SsDNA

Question 14

What is class 3 Baltimore classification?

Answer 14

DsRNA

Question 15

What is class 4 Baltimore scheme?

Answer 15

Positive ssRNA

Question 16

What is class 5 Baltimore scheme?

Answer 16

Negative ssRNA

Question 17

What is class VI Baltimore scheme?

Answer 17

Ss (+) RNA with DNA intermediate

Question 18

What is class VII Baltimore scheme?

Answer 18

DsDNA with RNA intermediate

Question 19

What is the maturation process?

Answer 19

Assemble a particle but it is not infectious so the maturation makes it infectious

Question 20

What are the stages of virus life cycle?

Answer 20

1. Binding
2. Entry (and Uncoating)
3. Protein expression
4. Genome replication
5. Virion assembly
6. Maturation
7. Release of particles

Question 21

What is examples of tissue tropism?

Answer 21

Measles (skin cells) vs mumps (salivary glands)

Question 22

What are examples of species tropism?

Answer 22

Togavirus (both insect/mammalian cells)
Poliovirus (primate cells)

Question 23

Where do RNA viruses often replicate?

Answer 23

In cytoplasm

Question 24

Where do DNA viruses often replicate?

Answer 24

In the nucleus

Question 25

What are the 3 types of structural proteins?

Answer 25

Capsid proteins
Envelope proteins
Matrix proteins

Question 26

What do alpha proteins mainly trigger?

Answer 26

Mostly transcription factors and then expression of beta genes to make beta proteins

Question 27

What do beat proteins do?

Answer 27

Accumulate and binds to promoters and transcription factors that allow expression of gamma genes and therefore gamma proteins