Exam 3: Viruses Part 1

Front 1

Define Obligate Intracellular Parasite (What bacteria fall under this category)

Back 1

Requires host cell to reproduce inside of
-Chlamydia & Rickettsia

Front 2

Why are viruses considered to be non-cellular/non-living

Back 2

-Lack CM, cytoplasm, ATP, and enzymes
-Nucleic acids (either or, not both)
-Can not reproduce on their on

Front 3

Give an example of strain specific and phage typing

Back 3

-E. coli B strain
-T4 strain phage attacks B strains

Front 4

Size of viruses

Back 4

1x10^-9 = nanometers

Front 5

What is the scientific term given to a colony of viruses? Define a colony of virus

Back 5

Plaque: Billions of viruses that originate from one cell

Front 6

List the different shapes of viruses

Back 6

-Helical
-Polyhedra/Icosahedral
-Cuboidal
-Round
-Complex

Front 7

Describe the nucleic acids in viruses

Back 7

-DNA or RNA
-Single or double stranded

Front 8

Describe the capsid structure in viruses

Back 8

-Capsomeres
-Proteins

Front 9

Describe the envelope in viruses

Back 9

-Optional
-Composed of phospholipid bilayer from host CM
-Covers capsid

Front 10

Describe the spikes in viruses

Back 10

-Optional
-Adherence

Front 11

How is a virus considered living?

Back 11

-Can reproduce (but not on its own)
-Have nucleic acids (not both)
-Have large macromolecules (ie. proteins)
-Can inactivate a virus (ie. heat)

Front 12

Describe the effect of heat on most viruses (include an exception)

Back 12

-Most viruses are inactivated at moderate temperatures (>60C)
-Exc: Hepatitis B (serum hepatitis) can withstand boiling for 10 min.

Front 13

Describe the effect of cold temperature on viruses

Back 13

-No effect
-Can withstand extreme cold (-76C)

Front 14

Describe the effect of pH on viruses

Back 14

-Extreme pH = inactivates viruses by denaturing DNA/RNA and proteins

Front 15

Describe the effect of desiccation/ drying on viruses

Back 15

-No effect

Front 16

Describe the effects of disinfectants/ antiseptics on viruses (include exception)

Back 16

-No effects
-Exc: oxidizing agents (ie. bleach, H2O2)

Front 17

Describe the effect of antibiotics on viruses

Back 17

No effect

Front 18

Describe the effect of UV light on viruses

Back 18

-No effect unless direct contact with UV light (ie. herpes simplex (cold sores))

Front 19

What are the 4 methods of cultivating viruses?

Back 19

-Lab animals & plants
-Chick embryos
-Cell cultures/ cell lines
-Bacterial cultures- Plaque assay method

Front 20

What is the disadvantage of using lab animals and plants for cultivating viruses

Back 20

Costly

Front 21

How are chick embryos used in the cultivation of viruses

Back 21

-For large numbers of viruses
-For vaccines

Front 22

What are the 3 ways of classifying viruses (include their types of method as well)

Back 22

-Type of host (general)
-Tissue affinity (general)
-Type of nucleic acid (most specific)

Front 23

Describe how viruses are classified by the type of host

Back 23

-Animal/ humans = animal/ human virus
-Plant = plant virus
-Bacteria = bacteriophage/ phage

Front 24

What are the 4 types of viruses classified by their tissue affinity

Back 24

-Neurotrophic (nervous)
-Dermatotrophic (skin)
-Viscerotrophic (viscera)
-Pneumotrophic (lung)

Front 25

What are 3 examples of neurotrophic viruses

Back 25

-Polio virus
-Rabies
-Herpes simplex (latent/ dormant in spinal cord)

Front 26

What are 3 examples of dermatotrophic viruses

Back 26

-Herpes simplex
-Chicken pox
-Measles

Front 27

What is an example of a viscerotrophic virus

Back 27

Hepatitis

Front 28

What are 2 examples of pneumotrophic viruses

Back 28

-Influenza
-Rhinovirus = cold

Front 29

Describe how viruses are classified by their nucleic acid

Back 29

-Either the DNA or RNA (not both) is either single stranded or double stranded

Front 30

Describe how a provirus goes from a latent infection to an active infection

Back 30

Latent (dormant) infection becomes an active infection spontaneously or by being induced (by chemicals, environmental factors, UV light)

Front 31

How does a provirus convert a normal host cell into a tumor cell

Back 31

-By introducing new viral oncogenes to host chromosome
-By activating/stimulating host proto-oncogenes to become oncogenes

Front 32

What is contact inhibition? What does a loss of contact inhibition result in?

Back 32

-Cells stop dividing with contact with nearby cells
-Result: tumor

Front 33

What is a prion?

Back 33

Proteinaceous infectious particle

Front 34

Who discovered prions? Where was it discovered?

Back 34

Stanley (1982)
-Scrapie (Neurological disease of sheep)

Front 35

Describe the resistance of prions

Back 35

Resistant to boiling, most disinfectants, and UV light

Front 36

How does an abnormal (lethal) PrP infect normal PrP

Back 36

Abnormal (lethal) PrP > contacts normal PrP > structurally alters and converts normal PrP into abnormal (lethal) PrP

Front 37

What will result if host if infected with prions?

Back 37

Abnormal (lethal) PrP accumulates in brain tissues and forms plaques

Front 38

What disease can abnormal prions cause?

Back 38

Spongiform encephalopath (large vacuoles develop in brain)

Front 39

List 4 prion diseases (Spongiform encephalopathies)

Back 39

-Scrapie (sheep)
-Kuru (cannibals in New Guinea)
-Mad Cow Disease (bovine spongiform encephalopathy/ BSE)
-Creutzfeldt-Jakob disease (CJD)

Front 40

How do prion disease break the species to species barrier?

Back 40

-Sheeps are fed to cows
-Humans eat cows

Front 41

Describe Creutzfeldt-Jakob disease (CJD)

Back 41

-Similar to mad cow disease
-Genetic
-Occurs in elderly people

Front 42

Describe the symptoms/ pathology of spongiform encephalopathies

Back 42

-Long incubation times, progresses slowly (15-20 years)
-CNS damage
-No immune response

Front 43

What would an autopsy of a person who has spongiform encephalopathies look like?

Back 43

Brain tissues show large vaculoes, porous, sponge-like (spongiform)