Virus + Non-Cell Microorganism Morphology

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