Mcgraw Hill: Microbiology Ch 6

Front 1

Virus

Back 1

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.

Front 2

Capsid

Back 2

The protein covering of a virus's nucleic acid core. They exhibit symmetry due to the regular arrangement of subunits.

Front 3

Nucleocapsid

Back 3

The close physical combination of the nucleic acid with its protective covering.

Front 4

capsomer

Back 4

A subunit of the virus capsid shaped as a triangle or disc.

Front 5

helical

Back 5

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.

Front 6

icosahedral

Back 6

A regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions have capsids that resemble icosahedral crystals.

Front 7

spikes

Back 7

A receptor on the surface of certain enveloped viruses that facilitates specific attachment to the host cell.

Front 8

Properties of Viruses

Back 8

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.

Front 9

Naked Viruses

Back 9

Those which only consist of a nucleocapsid

Front 10

Enveloped Viruses

Back 10

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.

Front 11

Adsorption

Back 11

The process in which a virus recognizes a susceptible host cell and connects to receptor sites on its membrane.

Front 12

Host Range

Back 12

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.

Front 13

Penetration

Back 13

The process by which either the whole virus or its just its nucleic acid penetrates the host cell membrane.

Front 14

Penetration by endocytosis

Back 14

the entire virus in engulfed by the cell and enclosed in a vacuole or vesicle.

Front 15

Uncoating

Back 15

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.

Front 16

Cytopathic effects

Back 16

The short and long term effects of viral infection on animal cells. Virus-induced damage to the cell that alters its microscopic appearance.

Front 17

transformation

Back 17

Term used to describe the effect of oncogenic or cancer-causing viruses on cells.

Front 18

oncoviruses

Back 18

mammalian viruses capable of initiating tumors

Front 19

Lysogeny

Back 19

The silent virus infection, a condition in which the host chromosome carries bacteriophage DNA and host cells do not lyse but appear entirely normal

Front 20

temperate phages

Back 20

Special DNA phages which undergo adsorption and penetration into the bacterial host but are not replicated or released immediately.

Front 21

Virus

Back 21

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.

Front 22

Capsid

Back 22

The protein covering of a virus's nucleic acid core. They exhibit symmetry due to the regular arrangement of subunits.

Front 23

Nucleocapsid

Back 23

The close physical combination of the nucleic acid with its protective covering.

Front 24

capsomer

Back 24

A subunit of the virus capsid shaped as a triangle or disc.

Front 25

helical

Back 25

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.

Front 26

icosahedral

Back 26

A regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions have capsids that resemble icosahedral crystals.

Front 27

spikes

Back 27

A receptor on the surface of certain enveloped viruses that facilitates specific attachment to the host cell.

Front 28

Properties of Viruses

Back 28

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.

Front 29

Naked Viruses

Back 29

Those which only consist of a nucleocapsid

Front 30

Enveloped Viruses

Back 30

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.

Front 31

Adsorption

Back 31

The process in which a virus recognizes a susceptible host cell and connects to receptor sites on its membrane.

Front 32

Host Range

Back 32

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.

Front 33

Penetration

Back 33

The process by which either the whole virus or its just its nucleic acid penetrates the host cell membrane.

Front 34

Penetration by endocytosis

Back 34

the entire virus in engulfed by the cell and enclosed in a vacuole or vesicle.

Front 35

Uncoating

Back 35

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.

Front 36

Cytopathic effects

Back 36

The short and long term effects of viral infection on animal cells. Virus-induced damage to the cell that alters its microscopic appearance.

Front 37

transformation

Back 37

Term used to describe the effect of oncogenic or cancer-causing viruses on cells.

Front 38

oncoviruses

Back 38

mammalian viruses capable of initiating tumors

Front 39

Lysogeny

Back 39

The silent virus infection, a condition in which the host chromosome carries bacteriophage DNA and host cells do not lyse but appear entirely normal

Front 40

temperate phages

Back 40

Special DNA phages which undergo adsorption and penetration into the bacterial host but are not replicated or released immediately.

Front 41

lytic cycle of T-even bacteriophage

Back 41

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.

Front 42

induction

Back 42

the process in which the prophage in a lysogenicl cell will be activated and progress directly into viral replication and the lytic cycle.

Front 43

lysogenic conversion

Back 43

when a bacterium acquires a new trait from its temperate phage

Front 44

Purpose of cultivating animal Viruses

Back 44

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.

Front 45

3 techniques for cultivating viruses

Back 45

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

Front 46

Importance of Viruses

Back 46

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.

Front 47

Prions

Back 47

Other noncellular agents of disease, are not viruses but protein fibers

Front 48

viroids

Back 48

extremely small lengths of protein-coated nucleic acid

Front 49

satellite viruses

Back 49

Require a larger virus in order to cause disease.