Microbiology Chapter 6

Front 1

Properties of viruses

Back 1

obligate intracellular parasites of bacteria, protozoa, fungi, algae, and plants, ultramicroscopic size, not cells, not considered to be living, inactive outside host cell and active inside host cell, lack enzymes for metabolic processes, lack machinery for synthesizing proteins, multiply by taking control of host cells genetic material, molecules on virus surface impart high specificity for attachment to host.

Front 2

What is the basic structure of a virus?

Back 2

protein shell (capsid) surrounding nucleic acid core

Front 3

What kinds of nucleic acid structures can viruses have?

Back 3

dsDNA, ssDNA, ssRNA, and dsRNA

Front 4

A virus particle covering consists of...

Back 4

capsid which all viruses have, and sometimes an envelope

Front 5

A virus particles central core consists of...

Back 5

nucleic acid molecules (DNA or RNA) and sometimes matrix proteins enzymes

Front 6

most stable form of covering that is a twenty sided capsid of a virus is called...

Back 6

isocohedron

Front 7

how are viruses viewed?

Back 7

electron microscopy

Front 8

What are viral capsids made of?

Back 8

proteins, subunits called capsomeres

Front 9

What are two general conformations of viral capsids?

Back 9

helical (rod-shaped capsomeres) and icosahedral (ring or dome shaped capsomeres)

Front 10

What helps with the attachment of icosahedral capsids?

Back 10

spike proteins

Front 11

What is the structure of the viral envelope?

Back 11

piece of membrane from the host cell which has been modified by the inclusion of viral proteins

Front 12

What does the viral envelope have included?

Back 12

plasma membrane, ER, and nuclear membrane

Front 13

How does the viral envelope get acquired?

Back 13

by a process called budding which is like stealing

Front 14

What are the functions of capsids and envelopes?

Back 14

protection for viral genome (protections from enzymes of host cells and from UV light damage) and for delivery of virus genome to host cell by attachment and penetration

Front 15

the complex viral structures

Back 15

inject virus into the cell

Front 16

How are viruses classified?

Back 16

by what kind of nucleic acid they use

Front 17

group 1 of viruses

Back 17

dsDNA

Front 18

group 2 of viruses

Back 18

ssDNA

Front 19

group 3 of viruses

Back 19

dsRNA

Front 20

group 4 of viruses

Back 20

(+) sense RNA

Front 21

group 5 of viruses

Back 21

(-) sense RNA

Front 22

group 6 viruses

Back 22

RNA reverse transcribing viruses

Front 23

group 7 viruses

Back 23

DNA reverse transcribing viruses

Front 24

example of dsDNA (group 1)

Back 24

Herpes Simplex Virus II or HPV

Front 25

example of ssDNA (group 2)

Back 25

parvovirus

Front 26

example of dsRNA (group 3)

Back 26

rotavirus

Front 27

example of (+) sense RNA (group 4)

Back 27

yellow fever

Front 28

example of (-) sense RNA (group 5)

Back 28

Ebola Virus

Front 29

example of RNA reverse transcribing (group 6)

Back 29

HIV

Front 30

example of DNA reverse transcribing (group 7)

Back 30

Hepatitus B

Front 31

Viral multiplication have these characteristics...

Back 31

adsorption, penetration, uncoating, synthesis, assembly, and release

Front 32

adsorption

Back 32

attachment

Front 33

penetration

Back 33

entry

Front 34

uncoating

Back 34

exposing the viral genome to the host cell machinery

Front 35

synthesis

Back 35

making new viral genomes and new viral proteins

Front 36

assembly

Back 36

putting the virions together

Front 37

release

Back 37

allowing the new virions to leave the cell

Front 38

tissue tropism

Back 38

specific to attachment

Front 39

What are the two principle means by which animal viruses penetrate?

Back 39

endocytosis (engulfment) and uncoating, or fusion of the cell membrane with the viral envelope

Front 40

genome copies make

Back 40

DNA replication, RNA transcription, and RNA reverse transcription

Front 41

Viral proteins made

Back 41

viral specific enzymes, new capsomere proteins, spike proteins, and matrix proteins

Front 42

How do cells release viruses?

Back 42

by budding : envelope viruses

Front 43

explain the life cycle

Back 43

adsorption, penetration, duplication of phage components, assembly of new virions, maturation, lysis of weakened cell, release of viruses

Front 44

Whats even smaller than viruses?

Back 44

prions, satellites, viroids

Front 45

assembly

Back 45

putting the virions together

Front 46

release

Back 46

allowing the new virions to leave the cell

Front 47

tissue tropism

Back 47

specific to attachment

Front 48

What are the two principle means by which animal viruses penetrate?

Back 48

endocytosis (engulfment) and uncoating, or fusion of the cell membrane with the viral envelope

Front 49

genome copies make

Back 49

DNA replication, RNA transcription, and RNA reverse transcription

Front 50

Viral proteins made

Back 50

viral specific enzymes, new capsomere proteins, spike proteins, and matrix proteins

Front 51

How do cells release viruses?

Back 51

by budding : envelope viruses

Front 52

explain the life cycle

Back 52

adsorption, penetration, duplication of phage components, assembly of new virions, maturation, lysis of weakened cell, release of viruses

Front 53

Whats even smaller than viruses?

Back 53

prions, satellites, viroids

Front 54

Adsorption

Back 54

the virus attaches to its host cell by specific binding of its spikes to cell receptors

Front 55

penetration and uncoating

Back 55

the virus is engulfed into a vesicle and its envelope is uncoated, thereby freeing the viral RNA into the cell cytoplasm

Front 56

Synthesis

Back 56

Under the control of viral genes, the cell synthesizes the basic components of new viruses; RNA molecules, capsomers, and spikes

Front 57

Assembly

Back 57

viral spike proteins are inserted into the cell membrane for the viral envelope; nucleocapsid is formed from RNA and capsomers

Front 58

Release

Back 58

Enveloped viruses bud off of the membrane, carrying away an envelope with the spikes. This complete virus or virion is ready to infect another cell.