Chapter 7 Vocabulary

capsid

a protein that surrounds the nucleic acid core. composed of capsomeres and spikes that attach virions to host cells

capsomeres

protein subunits that make up a viral capsid

nucleocapsid

capsid + nucleic acid

genome

the complete set of chromosomes and genes in an organism

host range

the limitation imposed by the characteristics of the host cell on the type of virus that can successfully invade it

reverse transcriptase

enzyme possessed by retroviruses that carries out the reversion of RNA to DNA ( a form of reverse transcription )

endocytosis

the process whereby solid and liquid materials are taken into the cell through membrane invagination and engulfment into a vesicle (cell eats stuff)

exocytosis

the process that releases enveloped viruses from the membrane of the hosts cytoplasm

(cell vomits viruses)

provirus

the genome of a virus when it is integrated into a host’s cell’s DNA

cytopathic effects (CPEs)

virus induced damage to host cells used for diagnosis. the cells can become disoriented and change shape/size, and develop intracellular changes

inclusion bodies

compacted masses of virus (in cytoplasm or nucleus) that damages cell organelles

syncytia

fusion of several host cells into large single cells; membrane fusion

prophage

an inactive stage where they persist in a bacterium by the integration of their DNA into the host chromosome, but do nor make new viruses

lytic cycle

the virus introduces its genome into a host cell and initiates replication by hijacking the host’s cellular machinery to make new copies of the virus. then the new copies break the cell and infect others

induction

process in which the prophage becomes active, enters replication and lytic cycle

lysogenic cycle

viruses sneak into the host’s DNA and stay hidden, later on gets induced, and infects other (much slower)

lysogenic conversion

when temperate phage gives bacteria new traits

plaques

clear patches of destroyed cells in observation

prions

“proteinaceous infectious agent” nickname

misfolded protein that causes other proteins in the brain to fold abnormally

viroids

infectious RNA particles smaller than viruses that disrupt cell metabolism by an unknown mechanism resulting in cell death (mostly infects plants)

satellite viruses/virophages

viruses that infect other viruses