Chapter 5 Flashcards
capsid in a virus
protein shell that surrounds the nucleic acid
nucleocapsid
the capsid and the nucleic acid together
envelope in a virus
the external covering of a capsid, usually a modified piece of the host’s cell membrane
what is a virion
a fully formed virus that is able to establish an infection in a host cell
retroviruses
carry own enzymes to create DNA out of their RNA
what class of virus is COVID
+ssRNA virus
phases of the animal virus replication cycle
adsorption penetration uncoating synthesis assembly release
host range
the limited range of cells that a virus can infect
tropism
specificities of viruses for certain tissues
2 types of penetration by animal viruses
1) endocytosis - entire virus is engulfed by the cell and enclosed in a vacuole or vesicle
2) direct fusion - envelope merges directly with the cell membrane, liberating the nucleocapsid into the cell’s interior
describe the early and late phases of dsDNA virus synthesis
early = viral DNA enters nucleus, genes are transcribed into mRNA; RNA transcript moves into the cytoplasm to be translated into viral proteins needed to replicate viral DNA
late = parts of the viral genome are transcribed/translated into proteins required to form the capsid and other structures; new viral genome and capsids assembled
how are nonenveloped and enveloped viruses released from the host cell
nonenveloped - reach maturation in the cell nucleus or cytoplasm and released when the cell lyses or ruptures
enveloped - liberated by budding from the membranes of the cytoplasm, nucleus, endoplasmic reticulum, or vesicles
what is syncytia
the fusion of multiple damaged host cells into single large cells containing multiple nuclei (giant cells)
what are inclusion bodies
compacted masses of viruses or damaged cell organelles in the nucleus and cytoplasm
transformation
the effect of oncogenic (cancer-causing) viruses on the cell
