Lecture 1: origin and history of viruses

Question 1

important cells that that are essential for recycling O, C, and N contents

Answer 1

bacteriophage

Question 2

origin of rabies, small pox and tulip breaking

Answer 2

mesopatomia (1000 BC)
ganges river area (500 BC)
holland

Question 3

discovered microscopic organisms

Answer 3

antonie van leeuwenhoek (1676)

Question 4

founder of virology

predicted microscopic infectious agents exist

Answer 4

jacob henle(1840)

Question 5

disproved spontaneous generation

Answer 5

louis pasteur (mid 1800s)

Question 6

enforced sterile techniques

Answer 6

joseph lister (1865)

Question 7

name Koch’s postulates (1876)

Answer 7

• regularly associate organism with disease
• isolate organism and grow in pure culture
• reproduce DISEASE with organism grown in pure culture
• re-isolate same organism from experimentally infected host

Question 8

transmitted tobacco mosaic disease agent using leaf sap

couldn’t “grow” agent in pure culture

Answer 8

adolf mayer (1876)

Question 9

first virus discovered

Answer 9

tobacco mosaic virus

Question 10

filtered plant sap retained infectivity

chamber filter

Answer 10

dimitri ivanofsky (1892)

Question 11

size of chamber filter that retains bacteria

Answer 11

0.2u

Question 12

filtered agent ONLY produced in plants

Answer 12

matinus beijernick (1898)

Question 13

slimy liquid or poison

Answer 13

virus

Question 14

infectious virus particle

Answer 14

virion

Question 15

what does a virion contain

Answer 15

protein and nucleic acid

Question 16

purified first virus (bacteriophage)

protein and nucleic acid present

Answer 16

schlessinger (1933)

Question 17

crystallized TMV

Answer 17

wendell stanley (1935)

Question 18

proposed that TMV contains RNA

Answer 18

bawden and pirie (1937)

Question 19

proposed that only turnip yellow mosaic virus (TYMV) particles containing nucleic acid are infectious

Answer 19

markham and smith (1949)

Question 20

proposed that DNA not protein that is heritable material

Answer 20

hershey and chase (1952)

Question 21

describe the hershey-chase blender experiment

Is DNA or protein the heritable material?

Answer 21

• used T2 DNA phage and E. coli
• labeled phage that infected cell: capsid protein (S35) and phage DNA (P32)

-labeled phage infects nonradioactive cell
-blended and centrifuge
-phage head removed from supernatant/infected cell
remains in precipitate
-progeny phages form; cell lyses
-progeny phage contain some labeled DNA

-DNA INHERITED NOT PROTEIN

Question 22

describe the fraenkel-conrat and singe experiment

Answer 22

• TMV can reassemble/ ripped apart
• multiple strains occur (mosaic strain and hypersensitive strain)
• HRV RNA and TMV coat protein assemble and form a “hybrid” virus, reconstituted, with HRV nucleic acid and TMV protein coat
• RNA not protein induces disease

Question 23

properties of a virus

Answer 23

• dependent on living host
• small, particle-like structures (nm range: 10^9, filterable, EM
• contain DNA or RNA (not both)
• viral genome associated with protein

Question 24

is a viron living?

Answer 24

no

Question 25

when is a virus “living”

Answer 25

infected host

Question 26

similarities and differences between virus and living organisms

Answer 26

• similarities
  
  • genome (DNA or RNA)
  • adapt to environment
  • reproduce
• differences
  
  • can’t capture/store energy -no metabolism gets form host
  • not functional outside host- obligate parasites
  • lack lipid biosynthesis

Question 27

7 characteristics of life

Answer 27

living things:

• composed of cells
• different levels of organization
• use energy
• respond to environment
• grow
• reproduce
• adapt to environment

Question 28

impact of viruses on humans, animals and plants

Answer 28

humans
-smallpox, measles, influenza, HIV, SARS, Ebola

animals
-foot and mouth, avian flu, rabies

plants
-coconut cadang-cadang, tomato spotted wilt