Transcript Document

What is a Virus?
Particle of nucleic acid and protein which
reproduce only by infecting living cells
Do viruses qualify as living things?
• Much smaller and less complex than cells
• Consist of either DNA or RNA enclosed in a protein
coat called a capsid
• Do not grow
• Have no nucleus, cytoplasm, or membranes
• Do not carry out cellular functions or generate
metabolic energy
Do viruses qualify as living things?
NO…They are obligate
intracellular parasites,
meaning that they require a
host cell to reproduce.
Lytic
Cycle
Lytic Cycle
(Viral Reproduction)
DOCKING with the host receptor protein
PENETRATION of the viral nucleic acid into the
host cytoplasm
BIOSYNTHESIS of the viral components
Assembly (MATURATION) of the viral components
into complete viral units
RELEASE of the completed virus from the host cell
Lysogenic
Cycle
Lysogenic
Cycle
Lysogenic
Cycle
Retroviruses
• Use RNA instead
DNA
of
Prions
• Protein infectious particles
• Contain no RNA or DNA
Interferon
• Protein produced by cells when exposed
to a virus.
• This protein binds to the cell membranes
of neighboring cells and "interferes" with
the ability of a virus to enter the cell.
Small Pox
Polio
Herpes Simplex
Hepatitis
Varicella Zoster
Mumps
Measles - Rubeola
Other Viruses
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Influenza Virus
Rubella
Parvo-virus
Epstein Barr Virus
Hanta Virus
(HPV) Human Papilloma Virus
(RSV) Respiratory Syncytial Virus
Rabies
Rhinovirus
Rotavirus
West Nile Virus