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51 Cards in this Set

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Charles Chamberland
Discovered porcelain filters used to filter (remove) bacteria.
Dmitri Ivanovsky
Discovered that some filtrates remained infectious???
Martinus Beijerinck
"Contagium vivium fluidium"
(Contagious living fluid)
Later coined the name virus
(meaning poison or venom)
isolate
propogate
observe and analyze was not available.
The lack of technology needed to: ________,_________, and ________________________ was lacking prior to the 1930s.
Wendell stanley
Crystallized the first virus (TMV)

Consisted of protein and RNA

Viruses first observed with an electron microscope.
Mendel's Particles
Gregor mendel

Certain inherited traits seem to be passed from parent to offspring as discrete hereditary "particles".
Hershey and Chase
Discovered the genetic material of some VIRUSES was DNA
1. Contain a single type of nucleic acid, either DNA or RNA.
2. Contain a protein coat (capsid) around the nucleic acid.
3. Some have a envelope (plasma membrane) around the protein coat.
4. Multiply inside living cells (Viruses can't synthsize proteins or generate ATP)
5. take over metabolic activity of host cells.
What are the general characteristics and structure of viruses?
capsomeres
Immunogenic
The general characteristic and structure of a virus consists of protein subunits called _________.

Is Antigenic/___________ (stimulates antibody production)
capsid
(Characteristic and structure of a virus)

Contain a protein coat (_______) around the nucleic acid.
envelope (plasma membrane)
Some viruses have an __________ around the protein coat.
synthesize
(Characteristic and structure of a virus)Multiply inside living cells (viruses can't _________ proteins or generate ATP).
host
Viruses take over the metabolic activity of _____ cells.
clinical
replication
Important for _________ control: Difficult to disrupt viral __________ without interfering with host cell function.
through an electron microscope.
What is the only way you can see a virus?
20-14,000 nm
What is the size of a virus?
Shapes of viruses
Helical/Spiral
Icosahedral (20 sided polyhedron)
Enveloped
Complex
heat
Most viruses are destroyed by >60' C, 140'F
Cold
This environmental effect has little effect on viruses.

They survive in -76' C for over 1 year.
Desiccation
This environmental effect tolerate drying on viruses.
pH
This environmental effect can tolerate from ranges ~5-9.
Disinfectants
This environmental effect are mostly ineffective on viruses.

Alcohol can destroy lipid enveloped viruses
Oxidizing agents
What environmental effect is mostly effective, and has to do with Hydrogen Peroxide, chlorine, and iodine.
UV light
What environment effect damages nucleic acids on viruses?
1. Living animals and plants
2. Embryonic eggs
3. Tissue/Cell culture
4. Bacterial culture
What is required for cultivation of viruses? (4)
Embryonic eggs
Virus is injected into embryonic tissues and membranes.
Tissue/Cell culture
Cells in solution that provides : nutrients, proper osmotic pressure, pH, etc.

include:
primary cell & embryonic cell lines
Continuous/immortal cell lines
primary cell & embryonic cell lines
Grow for a short time in vitro.
Continuous/immortal cell lines
Can be maintained in vitro indefinitely.
1. Attachment/Adsorption
2. Penetration
3. Biosynthesis
4. Maturation/Assembly
5. Release/Lysis
What are the 5 phases of T-even bacteriophage Lytic cycle?
Attachment/Adsorption
A phase in T-even bacteriophage lytic cycle

Phage tail fibers attach to specific receptors on bacteria.
Penetration
A phase in T-even bacteriophage lytic cycle

Phage release enzyme -> lysosome dissolves part of the bacteria cell wall. Tail sheath contracts and drives phage core through the cell wall and injects DNA.
Biosynthesis
A phase in T-even bacteriophage lytic cycle

Viral DNA takes over the machinery of the host cell and begins producing viral DNA and structural components.
Maturation/Assembly
A phase in T-even bacteriophage lytic cycle

Phage DNA assembles into complete viruses.
Release/Lysis
A phase in T-even bacteriophage lytic cycle

Phage lysosome breaks down bacterial cell wall and multiplied phages are released.
"burst time"
The time from adsorption to release.
"burst size"
The average number of virons released by a cell. (50-200 virons for T-even phage).
Lysogeny
Viral DNA is incorporated into the host DNA without causing lysis of the host cell.
Lysogenic cell

repressor protein.
A cell containing a prophage (provirus). Prophage genes are repressed by a _________ _______.
Latency
Ability to remain in host cells for long periods.
Induction/Excision
Specialized Transduction
What are the 2 phage conversions?
Induction/Excision
Certain environmental factors may cause a prophage to revert to the lytic cycle.

e.g. UV light or certain chemicals.
Specialized Transduction
When a prophage is excised from the host chromosome it can take with it adjacent DNA from the bacterial chromosome.
Animal viruses
Attachment
Penetration occurs by endocytosis
Uncoating by viral or host cell enzymes.
Biosynthesis
Maturation and Release (budding)
Latent viral infections
Virus remains in asymptomatic host cell for long periods. Reactivated by: fever, UV light, stress, trama, hormonal changes, and repair mechanisms in the cell.

eg. cold sores and shingles
Wilhelm Ellerman & Olaf Bang
F. Peyton Rous
Michael Bishop and Harold Varmus
Who worked on viruses and cancer?
Wilhelm Ellerman & Olaf Bang
Found that leukemia could be transferred to healthy chickens by cell-free filtrates containing viruses.
F. Peyton Rous
Found that chicken sarcoma (cancer of conn. tissue) similarly transmitted.

Oncogenes (cancergenes)
Oncogenes (cancergenes)
Genes that can cause a normal cell to be transformed into a malignant cell.
Michael Bishop and Harold Varmus
Won noble prize

Cancer-producing genes carried by viruses are derived from the animal cells genome.
Proto-oncogenes
Normally direct synthesis of products for cell growth and development. When a virus containing an oncogene is introduced into a cell, the cell may be unable to regulate synthesis of the virus's oncogene. The excess product may result in uncontrolled cell division.