XIII - Virology Flashcards Preview

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Flashcards in XIII - Virology Deck (366)
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1

Size of Viruses

20-300 nm

2

All viruses have a _____ coat.

protein coat (capsid), lipoprotein envelope in some

3

Virus capsids are composed of

repeating capsomeres

4

All helical viruses are

enveloped

5

Icosahedral (spherical) viruses can be enveloped or

naked

6

Viral Proteins

surface proteins, DNA or RNA polymerases, matrix protein, antigenic (serotypic) variants

7

Viral Proteins: Attachment to host cell receptors

surface protein

8

Viral Proteins: Interaction between nucleocapsid and envelope

matrix protein

9

Viral Proteins: Evasion of host defenses

antigenic (serotypic) variants

10

Lipid membrane derived from the host cell, acquired as the virus exits from the cell in a process called budding

viral envelope

11

All enveloped viruses acquire their envelope from plasma membrane except

herpesvirus - nuclear membrane

12

Enveloped viruses are _____ stable and _____ inactivated.

less stable, easily inactivated

13

Naked Viruses

RNA - Calici, Picorna, Reo, DNA - Parvo, Adeno, Papilloma, Polyoma

14

Purified nucleic acids of most dsDNA (except poxviruses and HBV) and (+) strand genome ssRNA viruses are

infectious

15

Naked nucleic acids of (-) strand ssRNA and dsDNA viruses are

not infectious

16

Naked nucleic acids of (-) strand ssRNA and dsDNA viruses require

enzymes contained in the complete virion

17

Infectious particles composed entirely of protein which case transmissible spongiform encephalopathies, highly resistant to inactivation, do not elicit an inflammatory response or an antibody response

Prions

18

Prion Proteins: Non-pathogenic

alpha-helix

19

Prions Proteins: Pathogenic

beta-pleated sheet

20

All viruses are haploid except

retroviruses

21

Genomes of RNA viruses can either have positive or negative

polarity

22

Some RNA viruses have a _____ genome.

segmented genome

23

Viruses with Segmented Genomes

Bunyavirus, Orthomyxovirus (influenza), Arenavirus, Reovirus

24

Must transcribe negative strand to positive, virion brings its own RNA-dependent polymerase

Negative-Strand RNA Viruses

25

Negative-Strand RNA Viruses

Arenavirus, Bunyavirus, Paramyxovirus, Orthomyxovirus, Filovirus, Rhabdovirus

26

Viral Genetics: Mutations can produce

antigenic, drug-resistant or attenuated variants

27

Viral Genetics: Causes epidemics

genomic reassortment

28

Viral Genetics: One virus produces a protein that can be used by another virus

complementation

29

Viral Genetics: Two different viruses infect the same cell

phenotypic mixing

30

Virus Life Cycle

attachment → penetration → uncoating → biosynthesis → maturation → release