Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
49 Cards in this Set
- Front
- Back
Virus
|
An infectious particle and not a cell; it lacks organelles and locomotion of any kind; they are large, complex molecules; they can be crystalline in form.
|
|
Capsid
|
The protein covering of a virus's nucleic acid core. They exhibit symmetry due to the regular arrangement of subunits.
|
|
Nucleocapsid
|
The close physical combination of the nucleic acid with its protective covering.
|
|
capsomer
|
A subunit of the virus capsid shaped as a triangle or disc.
|
|
helical
|
have rod-shaped capsomers that bond together to form a series of hollow discs resembling a bracelet. These discs link with other discs to form a continuous helix into which the nucleic acid strand is coiled.
|
|
icosahedral
|
A regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions have capsids that resemble icosahedral crystals.
|
|
spikes
|
A receptor on the surface of certain enveloped viruses that facilitates specific attachment to the host cell.
|
|
Properties of Viruses
|
Inactive macromolecules outisde the cell but active inside the cell. Do not independently fulfill the characteristics of life ex. can't metabolize, or synthesize proteins, or multiply w/o the host cell.
|
|
Naked Viruses
|
Those which only consist of a nucleocapsid
|
|
Enveloped Viruses
|
As its released from the host cell it takes with it a bit of its membrane system inthe form of an envelope. Some bud off the cell membrane and other leave via the nuclear envelope or the ER. The membrane has all of its regular membrane proteins replace when it becomes an envelope.
|
|
Adsorption
|
The process in which a virus recognizes a susceptible host cell and connects to receptor sites on its membrane.
|
|
Host Range
|
The range of hosts which a virus can infect that is typically limited because it can only infect a cell with which it can make an exact fit.
|
|
Penetration
|
The process by which either the whole virus or its just its nucleic acid penetrates the host cell membrane.
|
|
Penetration by endocytosis
|
the entire virus in engulfed by the cell and enclosed in a vacuole or vesicle.
|
|
Uncoating
|
After a virus has penetrated the host cell membrane by endocytosis, it is enclosed in a vesicle whose enzymes dissolve the envelope and capsid which releases the viral nucleic acid into the cytoplasm.
|
|
Cytopathic effects
|
The short and long term effects of viral infection on animal cells. Virus-induced damage to the cell that alters its microscopic appearance.
|
|
transformation
|
Term used to describe the effect of oncogenic or cancer-causing viruses on cells.
|
|
oncoviruses
|
mammalian viruses capable of initiating tumors
|
|
Lysogeny
|
The silent virus infection, a condition in which the host chromosome carries bacteriophage DNA and host cells do not lyse but appear entirely normal
|
|
temperate phages
|
Special DNA phages which undergo adsorption and penetration into the bacterial host but are not replicated or released immediately.
|
|
Virus
|
An infectious particle and not a cell; it lacks organelles and locomotion of any kind; they are large, complex molecules; they can be crystalline in form.
|
|
Capsid
|
The protein covering of a virus's nucleic acid core. They exhibit symmetry due to the regular arrangement of subunits.
|
|
Nucleocapsid
|
The close physical combination of the nucleic acid with its protective covering.
|
|
capsomer
|
A subunit of the virus capsid shaped as a triangle or disc.
|
|
helical
|
have rod-shaped capsomers that bond together to form a series of hollow discs resembling a bracelet. These discs link with other discs to form a continuous helix into which the nucleic acid strand is coiled.
|
|
icosahedral
|
A regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions have capsids that resemble icosahedral crystals.
|
|
spikes
|
A receptor on the surface of certain enveloped viruses that facilitates specific attachment to the host cell.
|
|
Properties of Viruses
|
Inactive macromolecules outisde the cell but active inside the cell. Do not independently fulfill the characteristics of life ex. can't metabolize, or synthesize proteins, or multiply w/o the host cell.
|
|
Naked Viruses
|
Those which only consist of a nucleocapsid
|
|
Enveloped Viruses
|
As its released from the host cell it takes with it a bit of its membrane system inthe form of an envelope. Some bud off the cell membrane and other leave via the nuclear envelope or the ER. The membrane has all of its regular membrane proteins replace when it becomes an envelope.
|
|
Adsorption
|
The process in which a virus recognizes a susceptible host cell and connects to receptor sites on its membrane.
|
|
Host Range
|
The range of hosts which a virus can infect that is typically limited because it can only infect a cell with which it can make an exact fit.
|
|
Penetration
|
The process by which either the whole virus or its just its nucleic acid penetrates the host cell membrane.
|
|
Penetration by endocytosis
|
the entire virus in engulfed by the cell and enclosed in a vacuole or vesicle.
|
|
Uncoating
|
After a virus has penetrated the host cell membrane by endocytosis, it is enclosed in a vesicle whose enzymes dissolve the envelope and capsid which releases the viral nucleic acid into the cytoplasm.
|
|
Cytopathic effects
|
The short and long term effects of viral infection on animal cells. Virus-induced damage to the cell that alters its microscopic appearance.
|
|
transformation
|
Term used to describe the effect of oncogenic or cancer-causing viruses on cells.
|
|
oncoviruses
|
mammalian viruses capable of initiating tumors
|
|
Lysogeny
|
The silent virus infection, a condition in which the host chromosome carries bacteriophage DNA and host cells do not lyse but appear entirely normal
|
|
temperate phages
|
Special DNA phages which undergo adsorption and penetration into the bacterial host but are not replicated or released immediately.
|
|
lytic cycle of T-even bacteriophage
|
It adsorbs to host bacteria using receptors, but only the nucleic acid penetrates the host after being injected through a rigid tube inserted through the bacterial membrane and wall which eliminates the need for uncoating. The nucleic acid ceases host cell DNA replication and protein synthesis, and uses host cell machinery for viral replication and synthesis of viral proteins. Viral parts spontaneously assemble into new viruses which fill the host cell until it lyses or splits open.
|
|
induction
|
the process in which the prophage in a lysogenicl cell will be activated and progress directly into viral replication and the lytic cycle.
|
|
lysogenic conversion
|
when a bacterium acquires a new trait from its temperate phage
|
|
Purpose of cultivating animal Viruses
|
1. To isolate and id viruses in clincial specimens. 2. To prepare viruses for vaccines 3. to do detailed research on viral structure, multiplication cycles, genetics and effects on host cells.
|
|
3 techniques for cultivating viruses
|
Viruses must be studies in some type of host cell environment: 1) live animal inoculation 2) bird embryos 3) using cell (tissue) culture techniques, virus growth is detected by the appearance of plaques
|
|
Importance of Viruses
|
They are responsible for several billion infection each year, and they are difficult to treat because the drugs that attack viral replication cycle also cause serious side effects in the host.
|
|
Prions
|
Other noncellular agents of disease, are not viruses but protein fibers
|
|
viroids
|
extremely small lengths of protein-coated nucleic acid
|
|
satellite viruses
|
Require a larger virus in order to cause disease.
|