Virus Structure

Question 1

When do most viruses assemble?

Answer 1

Self-assemble spontaneously

Question 2

Where is structural information found in viruses?

Answer 2

In proteins

Question 3

Why is the structure of a virus important?

Answer 3

For protection of the viral genome

Question 4

What does understanding the structure of a virus help with?

Answer 4

Design antibodies

Understand how viruses enter cells

Question 5

What are the features of self assembling viral structures?

Answer 5

Regular
Simple
Repeating = several copies of the same protein will interact to form the viral structure

Question 6

What is found inside the genome?

Answer 6

DNA or RNA

Question 7

What is the genome protected by?

Answer 7

Capsid

Question 8

What are capsomers?

Answer 8

Clusters of capsid proteins

Question 9

What is the capsid?

Answer 9

Capsomers joined to form a protective layer

Question 10

What structure forms around the capsid protected genome?

Answer 10

Viral envelope

Question 11

What is the viral envelope made of?

Answer 11

Envelope proteins which cluster to form peplomers

Question 12

What is the viral envelope?

Answer 12

A lipid bilayer

Question 13

What are the spikes on enveloped viruses?

Answer 13

Glycoproteins

Question 14

Do viruses always have an envelope?

Answer 14

No ; they can be enveloped or non-enveloped

Question 15

What does the capsid protect the genome from?

Answer 15

UV radiation
Extreme pH
Dehydration
Enzymatic attack

Question 16

What are the functions of the capsid?

Answer 16

Packaging and protecting DNA/RNA
Host cell recognition = by proteins on the capsid
Genomic material delivery

Question 17

What is the structure of a capsid?

Answer 17

Closed 3D structure with no holes = stable

Question 18

What do individual capsid units join to form?

Answer 18

Dimers

Question 19

What do dimers form?

Answer 19

Linear or triangular structures

Question 20

How are linear dimers further processed?

Answer 20

Coil to form helices which form rod shaped viruses

Question 21

How are triangular dimers further processed?

Answer 21

Combine to form larger triangular structures

Question 22

What form of viruses do larger triangular structures form?

Answer 22

Icosahedral viruses

Question 23

How many vertices do icosahedral viruses have?

Answer 23

12

Question 24

How many faces do icosahedral viruses have?

Answer 24

20 = equilateral triangles

Question 25

How many symmetry axes do icosahedral viruses have?

Answer 25

5-3-2

Question 26

How many subunits form an icosahedral shell?

Answer 26

60

Question 27

Can the same virus have different structures?

Answer 27

Yes

Question 28

Why is it important to know the specific 3D structure of a virus?

Answer 28

So that specific antibodies can be designed to disable viral replication

Question 29

How is zika virus transmitted and on what vector?

Answer 29

Between mother and child

Aedes mosquito

Question 30

What is polythetic classification?

Answer 30

Classification related to the number of characteristics which commonly occur within a group or class
- Characteristics are not essential in order to be part of the group

Question 31

What characteristics are used to determine groups in polythetic classification?

Answer 31

Target cells
Biochemistry
Structure
Genome sequence

Question 32

Do related viruses share the same characteristics?

Answer 32

Some but not all

Question 33

Do viruses have a common ancestor?

Answer 33

There is no evidence to show they do

Question 34

Do viruses interbreed?

Answer 34

No