assembly
fifth step in the virus life cycle, in which new viruses are created by packaging of the replicated genome into capsids
attachment
first step in the virus life cycle, in which a virion attaches to a host cell's surface
capsomere
collection or assembly of protein molecules making up a viral capsid
cytopathic effect
virus-induced structural change in a host cell that results in cell death, either through lysis (rupture) or inability to reproduce
endocytosis
form of bulk transport that moves material into a cell by an infolding of the cell membrane around the material, forming a vesicle (small sac) that moves into the cell
exocytosis
form of bulk transport used to move material outside the cell by fusion of a vesicle with the plasma membrane and release of the contents outside the cell
genome
genetic material of an organism
helical
type of symmetry of capsomere arrangement associated with spiral-shaped viruses
host range
range of cells—the types of organisms—that can host a virus
icosahedron
roughly spherical geometric structure with 20 triangular faces and the most efficient arrangement of capsomeres in a viral capsid
lysogenic conversion
transfer of genetic information from one bacterial host cell to another by a lysogenic virus
lysogeny
state in which most viral genes in a host cell are dormant and the viral genome (provirus) and host chromosome are integrated and replicated together
oncogenic
causing tumors to develop. With certain viruses, the effect occurs in host cells.
oncolytic viral therapy
a medical treatment that uses a modified virus to induce cell death (lysis) in tumors
penetration
second step in the virus life cycle, when the virion enters or injects its nucleic acid into the host cell
prion
misfolded protein that causes the proteins around it to become misfolded as well
provirus
genome of a virus in the lysogenic life cycle that is incorporated and replicated with the host chromosome
release
sixth and final step of the virus life cycle, when mature viruses leave the host cell
reverse transcriptase
enzyme that uses RNA as a template to make a DNA copy
synthesis
fourth step in the virus life cycle. It occurs when the virus directs the host cell's metabolism to produce the virus's nucleic acid and capsid protein.
uncoating
process that occurs in enveloped viruses when the virion enters a host cell and viral DNA or RNA is freed from the capsid and viral envelope
vaccination
technique of exposing an organism to a form of a pathogen to develop immunity against it
viral budding
process by which a mature virion leaves a host cell, borrowing contents of the host membrane to build its viral envelope as it exits
viral capsid
protein coat surrounding and protecting the viral genome
viral envelope
structure that consists of lipid-containing layers that surround the nucleocapsid of a virus
viral transformation
change to the host cell's physiology, biochemistry, or genetics because of the introduction of viral genetic information
virion
extracellular form of a virus which functions independently of a host
viroid
the smallest identified infectious agent composed simply of circular, single-stranded RNA without a protein coat
virus
infectious agent consisting of a nucleic acid strand within a protein coat