Virus Structure Flashcards
When do most viruses assemble?
Self-assemble spontaneously
Where is structural information found in viruses?
In proteins
Why is the structure of a virus important?
For protection of the viral genome
What does understanding the structure of a virus help with?
Design antibodies
Understand how viruses enter cells
What are the features of self assembling viral structures?
Regular
Simple
Repeating = several copies of the same protein will interact to form the viral structure
What is found inside the genome?
DNA or RNA
What is the genome protected by?
Capsid
What are capsomers?
Clusters of capsid proteins
What is the capsid?
Capsomers joined to form a protective layer
What structure forms around the capsid protected genome?
Viral envelope
What is the viral envelope made of?
Envelope proteins which cluster to form peplomers
What is the viral envelope?
A lipid bilayer
What are the spikes on enveloped viruses?
Glycoproteins
Do viruses always have an envelope?
No ; they can be enveloped or non-enveloped
What does the capsid protect the genome from?
UV radiation
Extreme pH
Dehydration
Enzymatic attack
What are the functions of the capsid?
Packaging and protecting DNA/RNA
Host cell recognition = by proteins on the capsid
Genomic material delivery
What is the structure of a capsid?
Closed 3D structure with no holes = stable
What do individual capsid units join to form?
Dimers
What do dimers form?
Linear or triangular structures
How are linear dimers further processed?
Coil to form helices which form rod shaped viruses
How are triangular dimers further processed?
Combine to form larger triangular structures
What form of viruses do larger triangular structures form?
Icosahedral viruses
How many vertices do icosahedral viruses have?
12
How many faces do icosahedral viruses have?
20 = equilateral triangles
How many symmetry axes do icosahedral viruses have?
5-3-2
How many subunits form an icosahedral shell?
60
Can the same virus have different structures?
Yes
Why is it important to know the specific 3D structure of a virus?
So that specific antibodies can be designed to disable viral replication
How is zika virus transmitted and on what vector?
Between mother and child
Aedes mosquito
What is polythetic classification?
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
What characteristics are used to determine groups in polythetic classification?
Target cells
Biochemistry
Structure
Genome sequence
Do related viruses share the same characteristics?
Some but not all
Do viruses have a common ancestor?
There is no evidence to show they do
Do viruses interbreed?
No
