Section 1

Question 1

Viruses are incapable of replication outside of a host cell therefore they are ______ ______

Answer 1

Obligate Symbionts

Question 2

Viruses ________ (do or don’t) have a single evolutionary origin

Answer 2

DO NOT

Question 3

Viruses have ______ genome complexities and effects on host

Answer 3

Varying

Question 4

Virus transmission can be via ______ _____ or other mechanisms

Answer 4

Extracellular virions

Question 5

Viruses can exist as _______ by having evolutionary overlap with other types of genetic information

Answer 5

Hybrids

Question 6

Phage M2 infects __ ____ and has ______ as its genome

Answer 6

Ecoli
+ve sense

Question 7

Pandoravirus infects _____ and has _______ as its genome

Answer 7

dsDNA

Question 8

most. viruses are transmitted between cells as ______

Answer 8

Virions

Question 9

A simple virion consists of _________ surrounded by a ____________

Answer 9

A nucleic acid genome, A capsid (protective protein layer)

Question 10

A virions nucleic acid genome + thecapsid (protective protein layer) = _________

Answer 10

Nucleocapsid

Question 11

Some viruses have more than a capsid and contain a lipid ______ as well

Answer 11

envelope

Question 12

The virion is (usually) ________ inside the host to release the genome

Answer 12

Disassembled

Question 13

Virus is Latin for _______

Answer 13

Poison

Question 14

Viruses were first identified as an infectious agent In 1890s by Martinus Beijerinck studying the disease of ______ ______

Answer 14

tobacco plants (tobacco mosaic virus TMV)

Question 15

Before the discovery of viruses, tulips were sold at very expensive prices because they had _____ ______ due to tulip mosaic virus

Answer 15

distinctive patterning

Question 16

Right after TMV was discovered in plants, ____ ____ _____ ______ was discovered in animals as caused by a virus

Answer 16

Food and mouth disease (virus FMDV)

Question 17

First cancer causing virus discovered in the early 1900s as ____ _____ ______ (because they took filters from a tutor and injected it into other people and it made another tumor)

Answer 17

Rous Sarcoma Virus

Question 18

First bacteriophage discovered in 1915 by _____ _____ and then in 1917 by Canadian ______ ______

Answer 18

Frederick Twort
Canadian Felix d’Herelle (by accident)

Question 19

Felix d’Herelle was studying shigella virus causing dysentery in children but his bacteria kept dying. THEREFORE, he accidentally discovered a type of viruses (bacteriophages) and successfully used it to treat Dysentery as ______ ______

Answer 19

Phage therapy

Question 20

1- Why is the study of viruses an important tool for human medicine? (5 things)

Answer 20

• Enzymes for molecular biology (cloning, protein manipulation etc)
  -CRSIPER gene editing*, **
  -Gene therapy
  -Phage therapy
  -Cancer therapy

*transplantation of pig heart into human after genetically modifying it
**pig example in the notes that had its PERVs inactivated to make LOW FAT pigs

Question 21

2- Viruses are important as strong selective forces on the ______ of the _____ by moving genes from cell to cell (viral and cellular genes)

Answer 21

Evolution of hosts

Question 22

3- Viruses are important as the most ______ entities on earth

Answer 22

Abundant

Question 23

4- Viruses contain most of the ____ _____ on Earth

Answer 23

Genetic Diversity

Question 24

Importance of Viruses (4 things)

Answer 24

• for medical and research reasons
• for evolution of hosts
• most abundant on earth
• most diverse on earth

Question 25

____% of the human genome is made of viruses (endogenous retroviruses) (ex. development of placenta is done by a protein that came from a retrovirus)

Answer 25

5%

Question 26

Viruses infecting bacteria are a frequent cause of different strains and they confer the benefits of ________ and cons of ________

Answer 26

Benefits: carry useful genes, may provide protection of infection by other virus Cons: time bombs that may become activated or go into lytic replication to kill the cell --> if single celled = :'(

Question 27

old time vaccination was called "Variolation" as _____ ______ developed the practice in 1790 to incubate cowpox to prevent smallpox

Answer 27

Edward Jenner

Question 28

______-________ is when immunity to one virus confers protection against a different closely related virus (ex cowpox and smallpox)

Answer 28

Cross-protection

Question 29

Vaccines eventually developed better to become _____ versions of a virus to still infect but with a milder disease

Answer 29

Attenuated

Question 30

Attenuated Vaccine was first developed against _____ by _____ ______

Answer 30

rabies by Lewis Pasteur ***cow infected with rabies BRAIN ----> mouse (spinal cord) -----> another mouse = milder and attenuated rabies

Question 31

Viruses were finally able to be grown in ________ in the 1950 which was a major advancement for vaccine development

Answer 31

In culture

Question 32

________ virus has particles bigger than most bacteria and genomes larger than most bacteria (broke the 'small' virus stereotype recently discovered ______ is even bigger

Answer 32

Mimiviruses Pandoravirus even bigger

Question 33

Patrick Forterre argued that a virion is not a virus RATHER the infected host is the virus (aka:_______)

Answer 33

virocell "a virus is like a seed is to a plant"

Question 34

Key points in the life of a virus are 1- 2- 3-

Answer 34

Getting in (attachment, entry, uncoating?) Doing stuff inside (transcription, translation, replication assembly) Getting out (exiting)

Question 35

Function of early genes expressed: Function of late genes expressed:

Answer 35

early= expression of genes that ALLOW replication to happen late= replication, assembly, packaging

Question 36

A virus getting into the cell is only possible if the cell has the right receptor making it __________

Answer 36

Susceptible

Question 37

A virus replicating inside a cell is one possible if cell has the correct things the virus needs _________

Answer 37

Permissive

Question 38

eukaryotic viruses and even phages show _______ (use different parts of cell for different activities)

Answer 38

Compartmentalization

Question 39

Viruses get out either by _____ or _____

Answer 39

Budding or lysis (some plant viruses even come out without particles covering them, just the genomic material moves)

Question 40

Transmission of viruses between hosts can be complex requiring different ______

Answer 40

Vectors

Question 41

Classification of viruses is most commonly done using the _________

Answer 41

Baltimore Scheme (7 categories by genome)

Question 42

Viruses can be grouped together based on _____, ______, _____ or _______

Answer 42

Host, Structure, Genome, Transmission mode

Question 43

Look up Baltimore classes of genomes *******

Question 44

The authority controlling virus taxonomy is _______ ______ on ______ of ________ (group of volunteers)

Answer 44

International Committee on Taxonomy of Viruses (ICTV)

Question 45

The 8 levels of taxonomy

Answer 45

Realm, Kingdom, Phylum, Class, Order, Family, Genus, Species (>1000 species)

Question 46

Names of taxonomic viruses are printed in ______ and first letters of names are _______

Answer 46

italics, capitalized

Question 47

_____ viruses require a helper virus to replicate

Answer 47

Satellite viruses

Question 48

_____ replicate independently but do not code for any proteins

Answer 48

viroids

Question 49

The three hypothesis about origin of viruses

Answer 49

1- viruses are the "last universal common ancestor" (LUCA) 2- viruses are derived from cells and are genetically reduced parasitic entities 3- viruses evolved from cells but escaped from cellular control after cells evolved into 3 domains

Question 50

Technologies that help us see viruses

Answer 50

electron microscopy, cryogenic-electron microscopy 3D, x-ray crystallography

Question 51

When viruses are composes of copies of multiple subunits It is good for _______ if a capsid has the same subunits it has _______

Answer 51

genomic economy symmetry

Question 52

if viruses can assemble spontaneously it is called ______

Answer 52

self-assembly

Question 53

Virus ______ = the geometry of its outline

Answer 53

shape

Question 54

Virus ______= the rotational and translation relationships that describe the shape

Answer 54

symmetry

Question 55

1- Viral Structure is called _________ = a shape with 20 triangular faces, with >2x rotational axis needing 3 copies of a protein to make on face

Answer 55

icosahedral symmetry

Question 56

using math to define symmetry of capsids is called ______ _______ as viruses get bigger and more complicated

Answer 56

triangulation number

Question 57

2- Viral structure is called ______ _____= fairly common with similar advantages to icosahedral

Answer 57

Helical symmetry

Question 58

Viruses with envelopes often get them from the _____ ______ through budding

Answer 58

cell membrane

Question 59

RG1:

Answer 59

Little to no risk, work on open bench

Question 60

RG 2+3

Answer 60

particular mask to prevent inhalation glasses to avoid splashes in eye gloves and lab coat work in biological safety cabinet

Question 61

RG3

Answer 61

compete isolation in suits