ch. 13 terminology Flashcards
virus
obligate intracellular parasites
basic components of viruses
biochemically dependent on the host cell
multiply successfully in living cells
no larger than 300nm
multiply by binary fission
do not contain both dna and rna
no ribosomes
limited metabolically
cannot multiply or make copies of themselves
not sensitive to antibiotics
viral tropism
virus ability to infect a specific cell or tissue
pantropic
affecting many types of tissues
incubation period
between time of exposure and first symptoms
virus enters body
infects lymph nodes
virus multiplies
produces viremia in the blood
virus spreads through the body and blood stream
Phase 2 of incubation
Disease– symptoms of a viral infection
acute infection
you either recover or die— appears suddenly and may be brief or prolonged duration
persistent infection
infection lingers for long periods of time
virus is not cleared but remains in specific cells of infected individuals
latent infection
lack of demonstrable infectious virus between episodes ( period of time during which no infection virus in produced) of recurrent disease
infectious agent present with no disease
chronic infection
virus is constantly being produced over a period of time
continued presence of infectious virus following the primary infection– may include chronic or recurrent disease
modes of virus entry
mouth
respiratory tract
nose
bite of arthropod (mosquito)
sexual interaction
broken skin –scratch
inoculation with a needle
virion
physical virus particle
nucleocapsid alone for some viruses (picornaviruses) or including outer envelope structure for others ( retroviruses)
capsid
regular shell-like structure composed of aggregated protein subunits which surrounds the viral nucleic acid
capsomere
morphological unit detected under electron microscope
nucleocapsid
CORE
viral nucleic acid enclosed by a capsid protein coat
