Chapter 5: Viruses Flashcards Preview

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Flashcards in Chapter 5: Viruses Deck (62)
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1

Seawater can contain ______ viruses per mL

100 million viruses per mL

2

Louis Pasteur

Postulated that a "living thing" smaller than bacteria was causing certain diseases; also proposed term "virus" (latin for poison)

3

Living characteristics of viruses (2)

  1. They reproduce at a fantastic rate, but only in living host cells;
  2. They can mutate

4

Non-living characteristics of viruses (2)

  1. They are acellular,
    1. that is, they contain no cytoplasm or cellular organelles;
  2. They carry out no metabolism on their own and must replicate using the host cell's metabolic machinery.

5

Parvoviruses

smallest viruses; 20 nm in diameter

6

Mimiviruses

largest viruses; 450 nm in length

7

Virus particles contain __________ DNA or RNA

either; not both

8

Viral Components (3)

  1. Nucelic Acid
  2. Capsid
  3. Envelope

9

Capside

protein shell that surrounds the nucleic acid

10

Nucleocapsid

the capsid together with the nucleic acid; naked viruses consist only of this

11

Envelope

external covering of a nucleocapsid; usually a modified piece of the host's cell membrane

12

Spikes

allow viruses to dock with host cell; can be found on BOTH naked and enveloped viruses

13

Virion

a fully formed virus able to establish an infection in the host cell

14

Capsomeres/Protomers

identical protein subunits that make up the capsid

15

Enveloped Virus

a virion with an envelope (most viruses that infect animals are enveloped)

16

Naked Virus

a virion without an envelope

17

How do envelopes form?

When viral glycoproteins and oligosaccharides associate with the cell membrane of the host cell

18

All envelopes have a _________

Phospholipid bilayer

19

Genome packaging plays an important role in ________

the infection

20

3 ways genomes are packaged:

  1. Directly in the capsid-inner side of the protein coat;
  2. Enclosed in special proteins-nucleic acid binding protein;
  3. Enclosed in proteins from the host cell

21

Variola Virus

small pox; double-stranded DNA

22

Herpes Simplex II

Herpes; double-stranded DNA

23

Parvovirus

Erythema Infectiosum; single-stranded DNA

24

Poliovirus

  • Poliomyelitis;
  • Single-stranded RNA;
  • (+) polarity

25

Influenza Virus

  • Influenza;
  • Single-stranded RNA;
  • (-) polarity

26

Rotavirus

  • Gastroenteritis;
  • Double-stranded RNA

27

HIV

  • AIDS;
  • Single-stranded RNA reverse transcriptase

28

Tobacco Mosaic Virus (describe shape)

hollow tubes with protein walls

29

Influenza Virus (describe shape)

an enveloped virus with a helical nucleocapsid

30

Icosahedral Viruses (describe shape)

derived from 20 triangular vases that make up the capsid; has 12 points of symmetry