V1: Virus classification Flashcards
(13 cards)
Define a virus.
A mobile genetic element that encodes at least 1 protein that is found encasing nucleic acid.
They are not cellular and are obligate intracellular parasites.
Define virion.
A virus particle.
What composes a virus?
Capsid & nucleic acid are required.
Can have enveloppes & other viral proteins but they are not required.
What are the types of capsids?
Helical
Icosahedral
Complex
Which viruses have helical capsids?
Rhabdoviruses, bunyaviruses.
Characteristics of viruses with helical capsids.
Can change shape to be either spherical or filamentous.
Characteristics of viruses with icosahedral capsids
Require 3 capsid proteins
Have a triangular shape
What viruses have icosahedral capsids?
Herpesvirus, picornavirus, parvovirus, adenovirus, rotavirus, retrovirus, papillomavirus.
Characteristics of complex capsids
Can have additional proteins attached to the capsid.
What viruses have complex capsids?
Poxvirus, bacteriophage
What are viral enveloppes made of?
Plasma membrane from the host cell
What are advantages & disadvantages of viral enveloppes?
Advantages:
- Hide the virus from the host’s immune system + allows virus to use host’s cellular pathways as the enveloppe is made from host cell material
Disadvantages:
- Virus are vulnerable w/o enveloppe but the enveloppe is usually not very resistant
What viruses have enveloppes?
Herpesvirus, poxvirus, coronavirus, orthomyxovirus
