Chapter 13, Exam Two Flashcards
Contain a single type of nucleic acid. Contain a protein coat. Multiply synthesizing machinery of the cell. Synthesis of specialized structures that can transfer the viral nucleic acid to other cells.
Viruses
Of a virus, is the spectrum of host cells the virus can infect.
Host range
Viruses are sensitive to interferon true or false
True
Viruses possess both DNA and RNA true or false
False
Narrow host range and ability to kill their host cells
Idea of phage therapy
Using bacteriophage to treat bacterial infections
Phage therapy
Viruses that may selectively in fact and kill tumor cells or cause any response against tumor cells
Oncolytic viruses
A complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by a protein coat outside a host cell
Viron
nucleic acid of a virus is protected by a protein coat
Capsid
Protein subunits of capsid
Capsomeres
Combination of lipids, proteins, and carbohydrates that cover a Capsid.
Envelope
Host cell’s plasma membrane coating animal virus. Extrusion process. May contain proteins determined by the viral nucleic acid and materials derived from normal host cell components.
Viral envelope
Carbohydrate – protein complexes that project from the surface of the viral envelope
Spikes
The capsid of this virus protects the nucleic acid from nuclease enzymes in biological fluids and promotes the viruses attachment to susceptible host cells
Non-enveloped to viruses
Helical viruses
Ebola and rabies
Polyhedral viruses
Icosahedron, 20 triangular faces and 12 corners
Roughly spherical, enveloped helical or enveloped polyhedral viruses
Enveloped viruses
Bacteriophage, structures such as the capsid, but tail sheath, tail fibers, base plate, and pin
Complex viruses
The international committee on taxonomy of viruses group viruses into families based on what?
Genomics and structure
A bacteriophage sample is mixed with host bacteria and melted agar. clearings or plaques are visible against a lawn of bacterial growth.
Plaque method
Each plaque corresponds to a single virus in the initial suspension. Concentrations of viral suspensions measured by the number of plaques are usually expressed in terms of…
Plaque forming unit PFu
Require living host cells in order to multiply
Intra-cellular parasites
When two or more strains of the virus combined to form a new subtype having a mixture of surface antigens of two or more original strains
Antigenic shift
Host for many animal viruses. A hole is drilled in the shell of an embryonated egg, and a viral suspension is injected into the egg’s fluid. Viral growth is signaled by the death of the embryo by embryo cell damage, or the formation of typical pox or lesions in the egg membranes. Vaccinations may have egg proteins.
Embryonated egg
Cells grown in culture media in a laboratory. Cell lines are started by treating a slice of animal tissue with enzymes that separate individual cells. Cells are suspended in a solution. Normal cells and here to glass or plastic and produce a monolayer.
Cell culture
Cell deterioration in cell culture is called
Cytopathic effect
Derived from tissue slices tending to die only after a few generations
Primary cell lines
Develops from human embryos, can be maintained for about 100 generations, widely used for culturing viruses that require a human host.
Diploid cell Lines
Transformed cancer cells that can be maintained through an indefinite number of generations, sometimes called immortal
Continuous cell lines
Serological method most used as a means of identification. Virus is detected and identified by it’s reaction with antibodies.
Western blotting
By infecting every cell in a culture and then testing the culture medium and cells for virions and viral proteins and nucleic acids. Growth curve looks like a single peak.
One step growth curve
Bacterial phage alternative mechanism/ lifecycle where lysis and death of the host cell occur
Lytic cycle
Bacteriophage can multiply by this cycle. Where the host cell remains alive.
Lysogenic cycle
Attachment, penetration, biosynthesis, maturation, and release.
Lytic cycle of t-even phage
Where a virus attaches to a complementary receptor site on the bacterial cell
Attachment, lytic cycle
Where a T even cell injects it’s nucleic acid into bacterium using phage lysozyme. Phage particle functions like a hypodermic syringe.
Penetration, Lytic cycle
Breaks down a portion of the bacterial cell wall
Phage lysozyme
Host protein synthesis is stopped by virus induced degradation of the host DNA, viral proteins that interfere with transcription, or the repression of translation. Initially, the phage uses the host cells nucleotides and several of it’s enzymes to synthesize many copies of phage DNA. Biosynthesis of viral proteins begins. The host cells ribosomes, enzymes, and amino acids are used for translation. Late messages are translated into phage capsid proteins.
Biosynthesis, lytic cycle
Multiplication is complete, infective virions are not present yet
Eclipse period
Phase in which viral component assemble into viral particles spontaneously
Maturation, lytic cycle