Microbiology - Test 3

Front 1

T or F viruses are infectious agents too small to be seen by the light microscope

Back 1

True. viruses are infectious agents too small to be seen by the light microscope

Front 2

T or F viruses are 5000 fold smaller than the cells they infect

Back 2

False. Viruses are 100 - 1000 fold smaller than the cells they infect

Front 3

T or F viruses are true cells

Back 3

False. Viruses are NOT true cells

Front 4

T or F viruses are obligate intracellular parasites

Back 4

true. viruses are obligate intracellular parasites

Front 5

T or F virions can contain RNA and DNA

Back 5

False. Virions contain only RNA or DNA. Never both

Front 6

Because of the small size of a virus, they contain little nucleic acid and very few ___

Back 6

Because of the small size of a virus, they contain little nucleic acid and very few genes

Front 7

T or F viruses are living organisms

Back 7

False. Viruses are NON-Living

Front 8

Viruses can infect what types of things?

Back 8

animals, plants, and other microorganisms

Front 9

define bacteriophage

Back 9

viruses that infect only bacteria

Front 10

define phage

Back 10

same as bacteriophage - viruses that infect only bacteria

Front 11

the size of a virus is measured in ____. most viruses range in size from ___ to ____

Back 11

the size of viruses is measured in nanometers (nm). most are between 10nm to 500nm

Front 12

Viruses contain (a) protein, DNA or RNA (b) protein, DNA, and RNA, (c) just protein (d) DNA

Back 12

A. protein, either DNA or RNA

Front 13

Viruses are totally dependent on _____ for replication

Back 13

host cell

Front 14

viral components must assemble into _____ in order to go from one host cell to another

Back 14

complete viruses

Front 15

another name for complete virus

Back 15

viroid

Front 16

shapes of viruses?

Back 16

isometric, helical, complex

Front 17

isometric virus

Back 17

isometric - nucleic acid surrounded by a polyhedral (many shape) shell or capsid (ex: adenovirus)

Front 18

helical virus

Back 18

ribbon like consist of nucleic acid surrounded by a hollow protein cylinder or capsid. possess a helical structure (ex tobacco mosaic virus)

Front 19

complex virus

Back 19

polyhedral head and helical sheath or tail; (ex: most phages)

Front 20

viruses will be either naked capsid or an envelope morphology. what does "naked virus" mean?

Back 20

naked viruses have protein capsids and nucliec acid. they are resistante and survive in the outside world

Front 21

what is enveloped virus

Back 21

envelope virus has a capsid, nucleic acid, and an envelope. they are susceptible to environmental factors such as drying, gastric acidity and bile

Front 22

T or F a capsid is a protein coat

Back 22

true

Front 23

T or F the shape of the virus is determined by the shape of the capsid

Back 23

true

Front 24

capsids are found in how many viruses? (a) most (b) a few (c) not many

Back 24

capsids are found in most viruses

Front 25

capsomere

Back 25

capsomeres are protein subunits; capsids are made of capsomeres

Front 26

capsids purpose?

Back 26

serves to PROTECT and INTRODUCE viral genome into host cell

Front 27

define nucleocapsid or naked virus

Back 27

viruses consisting of a genome surrounded by a capsid

Front 28

T or F attachment proteins project out from the capsid and bind the virus to host cells

Back 28

true

Front 29

Most animal viruses have ___

Back 29

an envelope

Front 30

a virus' envelope is similar to

Back 30

eukaryotic cell membrane; composed of a lipid bilayer

Front 31

where is an envelope derived from?

Back 31

derived from host cell membranes by a process called budding

Front 32

T or F enevlopes are usually of host cell origin; but the virus does incorporate proteins of its own, often appearing as glycoprotein spikes

Back 32

True

Front 33

the glycoprotein spikes function in ?

Back 33

spikes function in attaching the virus to receptors on susceptible host cells

Front 34

the nucleic acid of a virus will be what type? DNA or RNA?

Back 34

either a DNA or RNA

Front 35

the nucleic acid of a virus will be what type? single stranded, double stranded?

Back 35

single or double stranded

Front 36

the nucleic acid of a virus will be what type? linear, circular, or segmented?

Back 36

can be circular, segmented, or linear

Front 37

the nucleic acid of a virus will code for?

Back 37

codes for the synthesis of viral components and viral enzymes for replication

Front 38

T or F Viruses contain many enzymes in their capsid

Back 38

False. Viruses contain a few enzymes in their capsid

Front 39

Are the enzymes of viruses active or inactive? When does the inactive or active state of a virus change?

Back 39

Enzymes of viruses are inactive. They become active after the virus has entered the host cell

Front 40

What Enzyme does the HIV virus carry?

Back 40

HIV carries Reverse Transcriptase -- a RNA dependent DNA polymerase

Front 41

Animal Viruses: type of nucleic acid and its arrangement?

Back 41

animal viruses: DNA or RNA; single or double stranded; linear or segmented

Front 42

replication scheme for animal viruses?

Back 42

Lytic, Temperate, replication may occur in the nucleus or cytoplasm

Front 43

shapes of animal viruses

Back 43

spherical, rod, complex

Front 44

T or F animal viruses are not enveloped, only naked

Back 44

False. Animal viruses can be enveloped or naked viruses

Front 45

what is the replication cycle for viruses

Back 45

multiply in host cell only; uses host cell structures and enzymes; contains little nucleic acid

Front 46

the little nucleic acid that the virus contains, what is it used for?

Back 46

used to make the viral protein coat; assures replication of viral nucleic acid; moves the virus into and out of the host cell

Front 47

the replication cycle exists in two phases, inside the cell and outside the cell. explain

Back 47

outside the cell -- metabolically inert; inside the cell -- replication form

Front 48

in what ways can viruses be transmitted?

Back 48

inhaled ddroplets, food/water, direct transfer from other infected hosts, bites of vector, transplacental, sexually transmitted

Front 49

T or F viruses can infect only one or a restricted range of host species

Back 49

true

Front 50

T or F with viruses, there is a specific interaction between the nucleocapsid or virus membrane and host molecules

Back 50

true

Front 51

what are the types of relationships a virus can have with a host cell

Back 51

productive infection, extrude, latent infection, lysogenic cell

Front 52

define productive infection

Back 52

multiply inside the host cell and cause lysis phage -- called virulent phage or lytic phage

Front 53

define extrude

Back 53

some viruses leak out of the host cells w/o killing them

Front 54

with latent infection, the virus becomes a part of the genome of the host cell. T or F

Back 54

true

Front 55

define temperate phage

Back 55

due to latent infection; modify properties of the host cell phage

Front 56

define lysogenic cell

Back 56

a phenomenon called lysogenic conversion bacterial cell carrying a prophage is called lysogenic cell

Front 57

what are the stages of viral replication

Back 57

attachment, penetration, transcription, replication of phage DNA and synthesis of protein, assembly, release

Front 58

attachment phase

Back 58

virus must bind to specific receptor on surface of host cell

Front 59

penetration phase

Back 59

after few minutes, enzyme in the tip of the phage tail degrades small portion of the bacterial cell wall and the DNA is injected into the cell while protein coat of the phage remains on the outside

Front 60

transcription

Back 60

phage DNA in the host cell is transcribed into mRNA which is then translated into protein

Front 61

replication of phage DNA and synthesis of protein

Back 61

phage protein and nucleic acid replicate independently of one another.

Front 62

DNA from replication phase serves as two functions. What are they

Back 62

template for replication of more phage DNA, template for synthesis of mRNA

Front 63

assembly

Back 63

assembly or maturation process forms intact or mature phage. Once the phage head is formed it is packed with DNA. The tail is then attached, followed by the addition of tail spikes

Front 64

release

Back 64

enzyme lysozyme is synthesized to digest host cell from within; this results in cell lysis and the release of the phage

Front 65

with generalized transduction, can any bacterial gene be transferred?

Back 65

yes, any bacterial gene can be transferred.

Front 66

what types of phages carry out generalized transduction?

Back 66

generalized transducing phages carry out generalized transduction

Front 67

which types of phages serve as generalized transducing phages?

Back 67

virulent and temperate phages

Front 68

with generalized transduction, what happens?

Back 68

DNA from donor cell integrate into the recipient cell DNA by homologous recombination

Front 69

specialized transduction - what types of genes transfer?

Back 69

only a few specific genes

Front 70

what carrys out the specialized transduction?

Back 70

temperate phages ONLY (NOT virulent)

Front 71

with specialized transduction, a peice of bacterial DNA remains attached to the peice of phage DNA that is exised. T or F

Back 71

true

Front 72

with specialized transduction, when does the phage DNA replicate

Back 72

the phage DNA and the bacterial gene attached to the phage DNA replicate at the same time

Front 73

what genes are transduced with specialized transduction?

Back 73

Only genes located near the site at which the temperate phage integrates its DNA are transduced

Front 74

define balanced pathogenicity

Back 74

most viruses infect and persist within the hose in a state of BALANCED PATHOGENICITY in which the host is not killed

Front 75

viruses cause diseases classified as:

Back 75

acute or persistent

Front 76

define acute infetions

Back 76

acute infections: short duration, self-limited, virus is localized, may lead to lasting immunity (ex: measles, mumps, influenza, poliomyelitis)

Front 77

define persistent infections

Back 77

persistent infections can be: late complications following an acute infection, latent infection, chronic infection, slow infections

Front 78

Interactions of animal viruses with their hosts?

Back 78

attachment, entry, target site of viral replicaiton, uncoating, replication of nucleic acid and protein, maturation, release, shedding, transmission,

Front 79

when animal viruses interact with their host and attachment occurs, what does that mean

Back 79

fusion of viral envelope and host membrane

Front 80

where is viral replication in the host of an animal virus?

Back 80

either nucleus or cytoplasm

Front 81

what is uncoating

Back 81

in all viruses, nucleic acid separates from its protein prior to the start of replication

Front 82

in the maturation stage of animal virus, what happens

Back 82

protein formation occurs, protein coat and nucleic acid are assembled

Front 83

in the "release" stage of animal virus, what happens

Back 83

cell lysed; budding in persistant infection, or exocytosis

Front 84

shedding?

Back 84

shedding occurs from the same opening or surface that the virus enters from mucus, saliva, feces, etc