Introduction to virology

Question 1

Infectious obligate intracellular parasite with genetic material, protein coat, and membrane

Answer 1

virus

Question 2

viruses can infect all cellular life forms, found in soil, air and water

Answer 2

viruses are ubiquitous

Question 3

viruses cause disease in

Answer 3

animals
crop plants
industries with bacterial fermentation

Question 4

uses of bacteria

Answer 4

phage typing
enzyme sources
pesticides
anti bacterial
anti cancer agents
gene vectors

Question 5

viruses outnumber cellular life by :

Answer 5

10:1

Question 6

size of viruses

Answer 6

10-300 nm wide
20-800 nm long

Question 7

nucleic acid of viruses

Answer 7

either dna or rna
(bacteria have both)

Question 8

is protein present on viruses

Answer 8

yes (as with bacteria)

Question 9

are viruses cellular

Answer 9

no (bacteria are)

Question 10

do viruses have cytoplasmic membranes

Answer 10

no (bacteria yes)

Question 11

are ribosomes present

Answer 11

no (with one exception)

Question 12

do viruses geow and self replicate

Answer 12

no

Question 13

do viruses have a metabolism

Answer 13

no

Question 14

responsiveness of viruses

Answer 14

some phages respond to a host cell by injecting their genomes

Question 15

also called defective viruses because they have no protein

Answer 15

viroids

Question 16

genetic material present in viroids

Answer 16

only RNA

Question 17

has no genetic material but can self tepkicate through PrP proteins causing death in a matter or 3 months

Answer 17

prions

Question 18

does not induce immune response because it is similar to original protein

Answer 18

prions

Question 19

smallest viruses that infect bacteria

Answer 19

bacteriophages

Question 20

largest virus at 970 nm

Answer 20

ebola

Question 21

size of viruses

Answer 21

ultramicroscopic

Question 22

why do viruses not fulfil the characteristics of life

Answer 22

-lack of enzyme for metabolic processes
-lack machinery for synthesizing proteins

Question 23

viruses multiply by

Answer 23

assembly line method

Question 24

single folded polypeptide chain

Answer 24

subunit

Question 25

unit from which capsids or nucleocapsids are built

Answer 25

structural unit (protomer, assymetric unit)

Question 26

morphological unit that arise from interaction of the proteins within the repeated structural units forming capsid

Answer 26

capsomere

Question 27

protein shell surrounding genome

Answer 27

capsid

Question 28

host cell derived lipid bilayer

Answer 28

envelope (viral membrane)

Question 29

protein assembly within particle, used when there is a discrete substructure

Answer 29

nucleocapsid

Question 30

infectious virus particles

Answer 30

virion

Question 31

three parts of the viral structure

Answer 31

inner nucleic acid core
capsid
envelope

Question 32

DNA or RNA

Answer 32

inner nucleic acid core

Question 33

protein coat surrounding the nucleic acid

Answer 33

capsid

Question 34

found in some larger viruses

Answer 34

envelope

Question 35

associate to form the capsid

Answer 35

capsomeres

Question 36

has symmetric structure

Answer 36

helical – irregularly shaped and spiral
icosahedral – cubical with 20 flat sides

Question 37

shape of faces of an icosahedral viruses

Answer 37

equilateral triangle
5 at the top
5 at the bottom
10 around the middle
13 vertices

Question 38

three axes of symmetry

Answer 38

twofold
threefold
twofold