Chap 13- Virus Types & Characteristics

Question 1

Viral infections cause win/loss of wars; worldwide devastation due to this particular virus in earlier centuries , ________

Answer 1

smallpox (devastation)

Question 2

Virus & Christianity

Answer 2

Europeans who survived smallpox endemic brought the virus to the new world, killing droves of Aztecs while remaining untouched. Aztecs/new world inhabitants interpreted it as “Christian God” was dominant over their own

Question 3

Seasonal influenza first described by who?

Answer 3

Hippocrates, described as winter illness “Perinthus”

Question 4

Flu pandemics seemingly occur every ________.

Answer 4

Last flu pandemic before Rona was Spanish Flu of 1918 (affected 50mill, life expectancy dropped 12 yrs)

Question 5

naturally occurring minor changes in influenza viruses due to mutation

Answer 5

antigenic drift (small changes result of mutation)

Question 6

MAJOR changes where multiple strains of virus infect single host, and host can no longer recognize virus

Answer 6

antigenic shift (big changes due to multi attack on single host) (Ex: bird,pig, human flus mutating to one virus infecting single host)

Question 7

any substance that causes the body to make an immune response against it

Answer 7

antigenic

Question 8

Dmitri Ivanovsky was first to

Answer 8

isolate virus in tobacco plants & that the virus can pass through a filter. (sap from disease plants could transfer to healthy plants) (pores on filters too small for bacteria to pass, which led to discovery of viruses)

Question 9

Shortcomings & doubts with Ivanovsky’s experiment?

Answer 9

He did not fulfill Koch’s postulates as he was unable to grow the virus from infected sap on culture. This caused doubt (maybe filters were broken? maybe it was just a toxin?)

Question 10

Who proved Ivanovsky’s original findings?

Answer 10

M. Beijiernik showed SAP did not lose its disease ability despite after dilutions via multiple inoculations to healthy plants; dilution was not successful, so it cant be a toxin & it can replicate.

Question 11

Virus Characteristics

Answer 11

needs living tissue spread, are obligatory intracellular parasites, contain DNA OR RNA , have protein coat, most only infect specific cell type

Question 12

Virus in latin means

Answer 12

POISON

Question 13

Are viruses ALIVE?

Answer 13

They are considered noncellular life/ acellular infectious agent

Question 14

2 Things a Virus must have

Answer 14

Nucleic Acid (DNA or RNA - never both), Protein Coat

Question 15

range of cells, tissues, etc that a virus can affect

Answer 15

host range

Question 16

Viruses that infect Bacteria

Answer 16

Bacteriophages or “Phages”

Question 17

How do most viruses connect to host cells?

Answer 17

via attachment sites (receptor sites on host cells)& cellular factor (outer surface of virus chemically connects to receptor sites on host cell)

Question 18

Virus is generally these 3 shapes

Answer 18

icosahedral (20 flat triangles) , helical (capsomeres arranged in helix) , or complex (phage)

Question 19

viral particle aka

Answer 19

VIRION

Question 20

protein coat (of a virus)? made up of ? protects?

Answer 20

capsid; capsomeres; nucleic acid

Question 21

Nucleic acid & capsid make the ____

Answer 21

Nucleocapsid

Question 22

glycoprotein used for attachments to HOST cells (define the host range)

Answer 22

spikes

Question 23

type of virus that HAS lipid enveloper; type of virus that DOES NOT HAVE lipid envelope

Answer 23

Enveloped Virus; Naked Virus (Non Enveloped)

Question 24

outer lipid envelope derived from host’s plasma membrane that only SOME viruses have;

Answer 24

envelope

Question 25

Suffix virus FAMILIES end in?

Answer 25

Viridiae

Question 26

Genus end in “_____”

Answer 26

Virus (Ex: Enterovirus)

Question 27

Name of disease virus causes; indicates regions/intensity

Answer 27

Species (Ex: Poliovirus) *Viruses usually go by Species name)

Question 28

viruses who share ORAL TO FECAL route

Answer 28

enteric viruses

Question 29

viruses who share RESPIRATORY/ SALIVARY ROUTE

Answer 29

respiratory viruses

Question 30

viruses spread from animal to human & are literally the worse

Answer 30

ZOONOTIC viruses

Question 31

viruses that spread via insects

Answer 31

arboviruses

Question 32

Viral Genome Characteristics

Answer 32

VERY SMALL, only encodes its structural components (capsid proteins /enzymes) , which are only concerned about replicating its viral nucleic acids

Question 33

How do virus multiply? (Generalized)

Answer 33

Firstly, must invade host cell. Once virus inside, it takes over host cell expression machinery. Now, the cell starts to produce viral components. These viral components are assembled and result in virus leaving cell and causing cell burst/death.