Chapter 5

Question 1

What does it mean for a virus to be ‘Filterable’

Answer 1

when filtering out bacteria with porcelian filters, the filtrate left over was infectious. This result proved that an infection could be caused by a cell-free fluid containing agents smaller than bacteria and thus first introduced the concept of a filterable virus

Question 2

capsid

Answer 2

The protein covering of a virus’s nucleic acid core. Capsids exhibit symmetry due to the regular arrangement of subunits called

Question 3

nucleocapsid

Answer 3

In viruses, the close physical combination of the nucleic acid with its protective covering.

Question 4

virion

Answer 4

An elementary virus particle in its complete morphological and thus infectious form. A virion consists of the nucleic acid core surrounded by a capsid, which can be enclosed in an envelope

Question 5

enveloped virus

Answer 5

A virus whose nucleocapsid is enclosed by a membrane derived in part from the host cell. It usually contains exposed glycoprotein spikes specific for the virus.

Question 6

naked viruses

Answer 6

lack a envelope

Question 7

WHY DO antibiotics not work against viruses?

Answer 7

viruses lack the structures that antibodies work to inhibit or destroy

Question 8

Life cycles of animal viruses

Answer 8

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

Question 9

adsorption

Answer 9

adsorbs specifically to receptor site of susceptible host’s cell membrane. Glycoprotien spikes on capsid of virus bind to membrane receptors

Question 10

Penetration and uncoating

Answer 10

entire viruses is engulfed (endocytosed) by the cell and enclosed in a vacuole or vesicle. The vacuole uses enzymes to dissolve the outside of virus which is the uncoating and releases the viral nucleic acid into the cytoplasm of host

Question 11

Synthesis

Answer 11

replication and protein production directed by viral nucleic acid using the organelles of host cell

Question 12

assembly

Answer 12

mature virus particles constructed with new spikes to be picked up as the virus buds off with the hosts envelope

Question 13

Release

Answer 13

assembled viruses leave host in two ways

• nonenveloped and complex viruses are released when cell lysis
• enveloped viruses are liberated by budding from the membranes of the cytoplasm or other organelles and complete exocytosis

Question 14

host range

Answer 14

fitting with a particular receptor that a host cell presents

Question 15

cytopathic effect

Answer 15

The degenerative changes in cells associated with virus infection. Examples: the formation of multinucleate giant cells (Negri bodies), the prominent cytoplasmic

Question 16

syncytium

Answer 16

A multinucleated protoplasmic mass formed by consolidation of individual cells

Question 17

provirus

Answer 17

The genome of a virus when it is integrated into a host cell’s DNA.

Question 18

oncovirus

Answer 18

mammalian virus capable of causing malignant tumors

Question 19

bacteriophage

Answer 19

viruses that infect bacteria
most have double stranded DNA
can make bacteria more pathogenic
T-even phages like T2 and T4

Question 20

T-even bacteriophages

Answer 20

do not go the penetration part of life cycle
insert nucleic acid into host
most creepy form of virus yet

Question 21

temperate phage

Answer 21

a bacteriophage that enters into a less virulent state by becoming incorporated into the host genome as a prophage instead of the vegetative or lytic form that usually destroys the cell

Question 22

prophage

Answer 22

a lysogenized bacteriophage; a phage that is latently incorporated into the host chromosomes instead of undergoing viral replication and lysis

Question 23

lysogeny

Answer 23

the indefinite persistence of bacteriophage DNA in a host without bringing about the production of virions

Question 24

induction

Answer 24

the process whereby a bacteriophage in the prophage state is activated and begins replication and enters the lytic cycle

Question 25

lysogenic conversion

Answer 25

a bacterium acquires a new genetic trait due to the presence of genetic material from an infecting phage

Question 26

plaque

Answer 26

in virus propagation methods, the clear zone of lysed cells in tissue culture or chick embryo membrane that corresponds to the area containing viruses. i.e plague on our teeth that can cause big problems if not treated

Question 27

prion

Answer 27

: A concocted word to denote “proteinaceous infectious agent”; a cytopathic protein associated with the slow-virus spongiform encephalopathies of humans and animals.

Question 28

viroid

Answer 28

An infectious agent that, unlike a virion, lacks a capsid and consists of a closed circular RNA molecule. Although known viroids are all plant pathogens, it is conceivable that animal versions exist.

Question 29

Differentiating between viral infections and bacterial infections

Answer 29

viral infections cause milder symptoms
duration of symptoms, time of year and community illnesses
blood work, cultures and diagnostic tests

Question 30

hepititis B is associated with

Answer 30

liver cancer

Question 31

difference in replication of animal viruses vs bacterial virses

Answer 31

penetration

Question 32

Phage DNA encodes for the proteins of the viral capsid an

Answer 32

regulatory proteins which direct the production and assembly of the capsid proteins.

Question 33

causitive agent of shingles and the chicken pox

Answer 33

Varicella zoster virus

Question 34

Herpesviridae (DNA virus)

Answer 34

chicken pox, cold sores, varicella zoster virus

Question 35

Papovaviridae (DNA virus)

Answer 35

HPV

Question 36

Hepadnaviridae

DNA virus

Answer 36

hepatitis B

Question 37

Poxviridae (DNA virus)

Answer 37

small pox, variola and vaccinia virus

Question 38

Retroviridae(RNA virus)

Answer 38

rhinovirus

polomyelitis

Question 39

Flaviviridae

RNA virus

Answer 39

west nile virus

Question 40

Filoviridae RNA virus

Answer 40

ebola virus

Question 41

Rhabdoviridae RNA virus

Answer 41

rabies

Question 42

Retroviridae RNA virus

Answer 42

HIV HTLV