Intro to Virology Flashcards
- simple organization
- DNA or RNA genome
- unable to reproduce outside of living cells
- obligate intracellular parasites
Viruses
- complex organization
- DNA genome and RNAs
- carry out cell division
- some are obligate intracellular parasites
Cellular Organisms
_____ virus is bigger by far than any other known virus; and rivals bacteria
Pandoravirus
_______ viruses genomes are segmented and the segments are distributed into separate viral particles
Multicomponent
Multicomponent viruses genomes are segmented and the segments are distributed into separate _______
viral particles
____ theory of viral origin: viruses evolved by degenerative evolution from intracellular parasitic cells
Reductive origin
____ theory of viral origin: viruses evolved from functional parts of cells that acquired an ability to reproduce themselves uncontrolled by the cell
Intracellular origin
____ theory of viral origin: viroid nucleic acids could have evolved outside of cells during the RNA world and acquired the ability to infect cells
Independent origin
Cultivation of viruses requires _____ of living host cell
inoculation
\_\_\_\_\_\_\_\_\_\_ used for cultivation of viruses •suitable animals •embryonated eggs•tissue (cell) cultures –monolayers of animal cells –plaques •cytopathic effects (CPEs)
living host cell
–microscopic or macroscopic degenerative changes or abnormalities in host cells and tissues
cytopathic effects (CPEs)
DNA/RNA + structural proteins+ enzymes and nucleic acid- binding proteins form a _______
nucleocapsid
What form of symmetry is the HSV-1 and Bacteriophage T4 capsid?
Icosahedral
Filamentous virus is what symmetry?
Helical
If a virus only has a nucleocapsid, what is it referred to as?
Naked capsid virus
If a virus has a nucleocapsid and glycoproteins and membrane, it is referred to as _______
Enveloped virus
What is the difference between an enveloped and non-enveloped virus?
Glycoproteins and lipid bilayer
Vaccinia poxvirus is what viral symmetry?
Asymmetrical
Viruses are classified using a combination of what 4 properties?
- Type and structure of nucleic acid used for viral genome
- Presence or absence of envelope
- Type of capsid symmetry
- Replication strategy
What are the 5 steps of virus replication?
–adsorption –penetration and uncoating –synthesis of viral proteins and nucleic acids –assembly of virions –release
______ of Virions
•viral surface proteins and/or enzymes mediate attachment to specific host receptors
Adsorption
What are the 3 mechanisms of penetration and uncoating?
–injection of nucleic acid
–fusion of envelope with host membrane
–endocytosis
–encoded by late genes (Assembly of Virus Capsids)
capsid proteins
–empty procapsids formed then nucleic acid inserted (Assembly of Virus Capsids)
assembly of naked viruses
–in most cases, similar to assembly of naked viruses (Assembly of Virus Capsids)
assembly of enveloped viruses
–usually by lysis of host cell(Virion Release)
naked viruses
–formation of envelope and release usually occur concurrently(Virion Release)
enveloped viruses
- virus-encoded proteins incorporated into host membrane
* nucleocapsid buds outward and is surrounded by modified host membrane(Virion Release)
enveloped viruses
_____ are viral and are considered as part of the human virome
Bacteriophages
Which prophage is associated with Botulinum toxin?
Phage C1
Which prophage is associated with Diphtheria toxin?
Beta phage
Which prophage is associated with LPS synthesis?
Epsilon 34
Which human endogenous retrovirus (HERV) is associated with Syncytin-1?
HERV-W
Which human endogenous retrovirus (HERV) is associated with apolipoprotein C1?
HERV-E
The bacteriophage replication cycle is characterized by ____ release: produces viruses without killing the cell
Slow release
What are the 3 bacterial defenses against bacteriophages?
Genetic resistance
Restriction endonucleases
CRISPR
_________ –mutations in bacterial genes (e.g. receptor)(bacterial defenses against bacteriophages)
Genetic resistance
________–enzymes that cut invading DNA(bacterial defenses against bacteriophages)
Restriction endonucleases
________ –a bacterial immune system(bacterial defenses against bacteriophages)
CRISPR
______ therapy being explored as a potential antibiotic treatment
Phage therapy
_______ may limit the bacterial numbers to levels that the human immune system can tolerate; the particles may modulate immune system activity; they may attack biofilms
Phages
