Virion
viral unit that is infectious
Arguments that viruses are living
have rna/dna
reproduce
organised
Arguments that viruses are non-living
acellular
don't use energy or grow
can't reproduce alone
Viruses don't possess their own
enzymes
Provirus
viral genome integrated into host's chromosomes, multiplies with it
Capsid
Complex protein structures that surrounds the viral nucleic acid
________ capsid is the most efficient arrangement
icosahedral
Theory of quasi-equivalence
not all protein subunits equivalent, only some subunits can pack together
helical capsids are always ____ viruses
RNA
complex capsid components
bacteriophage with icosahedral head and helical tail
Functions of capsid
protects genome
makes shape
binds virions to specific receptors
capsid subunits are antigens
Functions of envelope
protects capsid
attaches to receptors
helps assemble new particles
Host-cell derived envelope contains
double lipid layer
M protein of viral envelope
on internal side
maintians integrity, assemble virions + releases virus, transports H+
Hemagglutinins of viral envelope
prismatic rods with triangular base
aids in receptors, induces antibody response, role in erythrocyte hemagglutination and hemadsorption
Neuraminidase of viral envelope
in orthomyoxirus and paramyxovirus, glycoprotein anchored in double lipid layer
helps virus penetrate into host cell, releases new viral particles from cell
Fusion profactors of viral envelope
in herpes and paramyxovirus, fuses envelope with membrane, disseminates infection and hemolysis
Genome - 4 types
ss/ds
linear/circular
segmented/non
pos/neg polarity
Nucleic acid can be found ________ or _________ into genome (provirus)
standalone, integrated
Structural enzymes are within _________ and non-structural enzymes are associated with the _______--
envelope, capsid
Role of viral enzymes
replicates viral genome and synthesizes viral proteins
Viriod
Single stranded RNA molecules that have no surrounding capsids
Viriods are localized in the
nucleoplasm and chloroplast
Viriods can replicate in the ________
nucleus
Ribozyme
viroid RNA that can act as an enzyme
Prions
infectious protein particles that do not have a genome
What microorganisms cause BCJ, BGSS, fatal familial insomnia and kuru in humans?
prions
Prion disease characreristics
long incubation period + slowly progressive
neuro symptoms
heredofamilial
Prions do not have a
immune response
Prion-protein (PrPsc)
cleavage product of precursor protein (PrPc), on surface of neurons
PrPsc roles
interacts with acetylcholine recepots
conserves info
sleep regulation
nutrient for purkinje cells
Pathogenicity of prion-protein (brain damage)
transports deficiencies on cell surface, accumulates in brain, makes filamentour aggregates and disorganizes brain
Prion-protein causes _________ of neural bodies, dendrites and axons and excessive _________ proliferation
vacuolization, astrocytic
Entryways of prions
oral or parenteral
The only certain way to diagnose prions
postmortem - histopathological brain lesions
Bacteriophage
A virus that infects bacteria
Hexagonal head of bacteriophage
proteic capsid w/ dna
Tail of bacteriophage
cylinder wrapped in myosin-like protein, basal hexagonal plate w/ enzyme (like lysosome) + attaching fibers
First step of bacteriophage replicative cycle
Attachment on the surface of bacterial wall w/ specific wall receptors
Second step of bacteriophage replicative cycle
Contraction of tail - bacteriophage injects dna into cell
In bacteriophage replication, the phage genome will synthesize new identical phages and ribosomes will synthesize
capsid and tail proteins
Lysogenic cycle vs release stage of replication of bacteriophage
genome of bacteriophage transmit to daughter bacteria + prophage activates vs. bacterial cell lysed + bacteriophages burst out
Administration of a mixture of _______ to treat and prevent infections (bacteriophage)
phages
Phage typing
test for determining which phages a bacterium is susceptible to (source of outbreaks)
double-strandded DNA ________ w/ icosahedral symmetry + part of lavidaviridae family
Virophage
Virophage is parasitic virus that coinfect ____________ ______ together with giant viruses from Mimiviridae family
eukaryotic cells