Structure & Chemical Composition of Viruses Flashcards
What is the smallest virus
Porcine Cirocovirus Type 1 (17nm) , followed by parvovirus (18nm)
What is the largest virus?
Pandoravirus (400nm) the step below it is the poxvirus (200nm)
what is pleomorphism?
the ability of some virus to alter their shape or size
What is the morphology of a virus?
DNA or RNA genes surrounded by a capsid, surrounded by an envelope (a bubble of fat), then molecules of protein on the envelope
what is a capsid?
the protein shell of a virus that encases / envelopes the viral nucleic acid or genome.
what is the capsid made up of?
capsomeres held together by non-covalent bonds
what is the basic sub-unit protein in the capsid of a virus?
a capsomere
what is a nucleocapsid?
Capsid + Virus nucleic acid (DNa/RNA)/genome
because of the interaction between the nucleic acid and capsid proteins…
incomplete virions (empty helical partricles) cannot form.
in all animal viruses the helical necleocapsid is..
enclosed within a lipoprotein envelope
naked helical necleocapsides are common among..
plant viruses
what are the two types of capsomers present in the icosahedral capsid?
(spherical Viruses) pentagonal capsomers at the verices (pentons) and hexagonal capsomeres making up the facets (hexons)
there are always ___ pentons?
12 (spherical virsues)
the number of hexons ______
varies with the virus group (spherical viruses)
what is the Trangulation number?
describes the relation between the number of pentagons and hexagons of the icosahedron the larger the T-number the more hexagons are present relative to pentagons
