01: Structure and Classification

Components common to every virus

Nucleic acid genome and a capsid

Capsid building blocks

Proteins called capsomeres

How does a virus end up enveloped

It steals lipids from a host cell or organelle during replication

Molecule that is occasionally present on an envelope

Glycoproteins

Regions of a viral genome

• Structural: codes for viral proteins

• Non-structural: codes for factors and proteins that assist with viral replication

• Third regions for secondary and tertiary structure

Variations in viral genome

• DNA or RNA

• ss or ds

• Linear or circular (DNA)

• Linear or segmented (RNA)

Direction of a positive sense nucleic acid strand

5’ → 3’

Direction of a negative sense nucleic acid strand

3’ → 5’

Function of a capsid

• Protects the genome from the environment

• Opens when the genome needs to be released into host cells (metastable)

• Interacts with host cell receptors

Function of envelope glycoproteins

Helps facilitate receptor interaction

Capsid shapes

• Icosahedral

• Helical

• Complex

Term for single viral particle

Virion

Type of virus that is typically the largest

Enveloped dsDNA virus

Suffix indicating a viral family

-viridae

Suffix indicating a viral genus

-virus

Suffix indicating a viral species

-virus