MCM 2-1 Virus Structure & Classification Flashcards Preview

MSI Unit II > MCM 2-1 Virus Structure & Classification > Flashcards

Flashcards in MCM 2-1 Virus Structure & Classification Deck (19)
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1

definition of a virus

an organism that encodes a capsid that is an obligate intracellular parasite associated with all life forms

2

definition of a virion

the particle encoded by a virus genome

consists of a genome, capsid, and optional envelope

3

how are viruses classified?

by host cell (eukaryotic/ prokaryotic, plant/insect/animal)

by viral genome type (RNA or DNA, single or double stranded)

by virion structure (enveloped or naked, helical/icosahedral, or complex

4

what is the basic structure of a virus or "the viral genome must have the following three modules"

three basic gene modules

1. capsid proteins - structural because they form the virion. encoding molecule

2. the replicon which encodes nucleic acid polymerase, replication origin, necessary accessory proteins

3. multifactorial proteins that interact with the host. Non-structural because they are left behind in the infected cell and not packed into the virion

5

unifying principles of virology

All viruses follow a three-part strategy for survival

1. Genome encodes a capsid that protects it outside the cell

2. Genome contains info for infecting a cell, replicating the genome, intracellular survival, and virion assembly

3. Transmission to new host is required to maintain the virus as a species

6

what led to the discovery of viruses?

diseases led to their discovery, known as "filterable agents"

7

viruses have a _____ genome

modular. it encodes for the capsid, replicon, and host interacting factors

8

what happens to virions outside of the host cell

they are inert and lose infectivity over time

9

virions consist of (3)

a few genes, encased in a protein shell, may or may not be enveloped in a membrane

10

genome

can be DNA or RNA and can be ss, ds, circular, etc.

11

nucleocapsid/capsid/core

protein shell that encapsulates genome

can have helical symmetry due to rolling effect of subunits

or icosahedral symmetry - 20 faces

12

tegument

cluster of proteins outside of the nucleocapsid

13

matrix

proteins that link the core to the envelope

14

envelope

lipid bilayer which can surround the virion

15

glycoprotein

glycosylated proteins found on the outside of envelope

16

spike/fiber

glycoprotein that sticks out, important for attachment and specificity

17

describe adenovirus

icosahedral, dsDNA, naked

DIN

18

describe influenza

helical, dsdna, enveloped

HED

19

describe herpes

icosahedral, dsdna, enveloped

DIE

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