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Microbiology Exam I > Basic Virology > Flashcards

Flashcards in Basic Virology Deck (31)
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1
Q

What 2 bacteria require living cells to survive?

A

Chlamydia and Rickesttsiae

2
Q

Do viruses need living cells to survive?

A

Yes, they are obligate intracellular parasites

3
Q

Viruses consists of

A

NA (DNA or RNA, not both) and proteins, some possess an envelope

4
Q

Viruses are simple replicons, yet

A

they can take over the host cells machinery and use hots enzymes for replication

5
Q

Size of viruses

A

15-300nm, must use ELECTRON microscopy

6
Q

Virion

A

complete viral particle, able to infect host and replicate

7
Q

Genetic material

A

dsDNA, ssDNA, (+)ssRNA, (-)ssRNA, dsRNA with identical or complementary strands, linear or circular, usually condensed with histones

8
Q

Each infectious virion possess the same

A

NA

9
Q

Protomer

A

protein subunit of the capsid (viral protein envelope)

10
Q

Protomers can be arranged 2 ways:

A

icosahedral or helical

11
Q

Capsomers

A

arrangement of protomers that form a capsid with icosahedral symmetry

12
Q

capsid

A

protein shell that self-assembles from protomers and encloses a core of NA

13
Q

There are 3 architectural structures of a capsid

A

complex symmetry, cubic/icosahedral symmetry, helical symmetry

14
Q

Complex symmetry

A

viruses with unresolved arrangements (not solved yet)

15
Q

cubic/icosahedral symmetry

A

20 faces, each is an equilateral triangle, protomers arranged into capsomers

16
Q

helical symmetry

A

enveloped or non-enveloped nucleocapsid formed by a single repeating protomer and ssRNA

17
Q

nucleocapsid:

A

protomers assembled in a helical structure around the nucleic acid genome of the virus (capsid + NA + associated proteins)

18
Q

Nucleocapsids can be enveloped or not, non-enveloped nucleocapsids are

A

stable, resistant to desiccation, acids, and detergents

19
Q

Nucleocapsids may have an envelope that is derived from

A

host NM, CM, or organelle membrane

20
Q

Peplomer

A

protein on surface of enveloped nucleocapsids (spikes) that play a role in attachment to cell receptor

21
Q

Tegument and Matrix protein

A

layer between envelope and nucleocapsid that has complex function and maintains shape

22
Q

Nucleocapsids can be enveloped or not, enveloped nucleocapsids are

A

fragile, easily disrupted/denatured, sensitive to desiccation and detergents

23
Q

If an enveloped virus is disrupted

A

the virus becomes inactive

24
Q

Nearly ALL enveloped viruses are transmitted via

A

arthropods in respiratory droplets or bodily fluids

25
Q

Viruses are classified by 4 categories:

A

type and polarity of NA, type of capsid symmetry, presence of envelope, quantitative measure of capsid architecture

26
Q

5 Orders of Viruses

A

Caudovirales, herpesvirales, mononegavirales, nidovirales, picornavirales

27
Q

Viral clade

A

all descendants from a common ancestor as determined by sequence similarity w/in clade and sequence variation among population

28
Q

Virus serotypes

A

based on antigenic diversity

29
Q

Examples of clades (Hepatitis C)

A

6 major clades with genotypes differing by 30-50%

30
Q

Quasisepsis

A

chronic viral infection that spontaneously generates a population of virions with significant diverse genomics

31
Q

Medical significance of clades:

A

immune evasion