Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

vm639: virology > Introduction to Virology (Exam 1) > Flashcards

Introduction to Virology (Exam 1) Flashcards

1
Q

General Characteristics of Viruses

A

Small (20-300nm), filterable
Simple
Obligate intracellular parasites
Infectious
Include important pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 virus structures?

A

Helical, icosahedral, complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 types of icosahedral viruses and what subtypes are included under those?

A

Non-enveloped: DNA genome or RNA genome
Enveloped: DNA genome or RNA genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type or viruses make up helical viruses?

A

Enveloped, RNA genome
Rhabdoviridae (rabies), Orthomyxoviridae (influenza), Paramyxoviridae (measles), Filoviridae (ebola)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define: Virion

A

Complete virus particle (at minimum consists of viral nucleic acid and viral proteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define: Capsid

A

Protein shell which surrounds the viral nucleic acid
Protect viral genome from destructive agents
Introduction of viral genome into host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define: Nucleocapsid

A

Capsid + Nucleic Acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define: Envelope

A

Lipoprotein outer covering of virions of some viruses
Derived from cellular membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define: Capsomers

A

A cluster or proteins that make up one morphologic unit as seen by electron microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are important practical considerations of viruses?

A

Structure provides protection of the genome from the environment
Contains the viral attachment proteins (VAP) that interact with the cellular receptors; therefore determine tropism
Identification and categorization of viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 3 components of a virus?

A
  1. Proteins and glycoproteins
  2. Nucleic Acids (DNA or RNA)
  3. Lipids (envelope)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 2 types of viral proteins?

A

Structural
Non-Structural

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Characteristics of structural proteins

A

Make up the virion
Protect the genome
Viral attachment protein(s) determine tissue tropism
Antigens that induce neutralizing antibodies, CTLs, T helper cells
In some virus families, enzymes and regulatory proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Characteristics of non-structural proteins

A

Encoded by the viral genome and expressed in infected cells
NOT a part of the virion
Replication functions (like enzymes and regulatory proteins)
Host-interaction functions (e.g. virokines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 2 types of DNA viral genomes?

A

Double-stranded DNA: linear (pox, herpes, adeno), circular (papova, hepadna)
Single-stranded DNA: linear (parvo), circular (circo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 2 types of RNA viral genomes?

A

Double-stranded RNA: (reo)
Single-stranded RNA: positive-sense (corona), negative sense (paramyxo, rhabdo), ambisense (bunya, arena)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the difference between DNA and RNA polymerases?

A

DNA dependent DNA polymerase have editing functions that result in LOW mutation rates
RNA dependent RNA polymerases are error prone resulting in HIGHER mutation rates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Do DNA or RNA polymerases have a higher mutation rate?

A

RNA polymerases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define: Reassortment

A

Genetic shift
Mixture of parental strains
Consequence of segmented genome

20
Q

Is DNA or RNA more durable?

A

DNA

21
Q

What can degrade RNA?

A

RNAases, heat, formaldehyde, UV light

22
Q

What can degrade DNA?

A

Relatively more durable than RNA in tissues, but can be degraded by DNAases and heat

23
Q

Define: Monopartite

A

Single nucleic acid molecule protected in a shell made of proteins (and sometimes also lipids) forming the virus particle
Ex. Paramyxovirus

24
Q

Define: Multipartite

A

Existing as two or more separate but incomplete particles
Segmented
Ex. Orthomyxovirus

25
Q

Define: Diploid

A

2 genetically identical RNA molecules
Ex. retrovirus

26
Q

What is the origin of viral envelopes?

A

Intracellular membranes via budding

27
Q

Characteristics of Non-Enveloped Viruses

A

Generally resistant to environmental conditions and disinfectants
Ex. canine parvovirus 2

28
Q

Characteristics of Enveloped Viruses

A

Fragile and easily inactivated by environmental conditions, soap, and other lipid solvents
Ex. parainfluenzavirus-3
Envelopes are easy to eliminate

29
Q

How are viruses classified?

A

Structure of the virion
Type of genome (DNA/RNA, single/double stranded, positive/negative/ambi-sense, linear/circular/diploid/segmented, gene arrangement)
Nucleotide sequence
Pathophysiology (enteric, respiratory, oncogenic)
Transmission (arthropod-born, rodent-born)

30
Q

Order, Family, Subfamily, Genus of Viruses

A

Order: virales
Family: viridae
Subfamily: virinae
Genus: virus

31
Q

How do viruses replicate themselves?

A

Viruses use the machinery and metabolism of a host cell to produce new copies of themselves

32
Q

What are the (10) steps in viral replication?

A
  1. Attachment
  2. Penetration
  3. Uncoating
  4. Transcription of early mRNA
  5. Translation of early proteins
  6. Replication of viral DNA
  7. Transcription of late mRNA
  8. Translation of late proteins
  9. Assembly of virions
  10. Release
33
Q

What type of attachment is present in viruses?

A

Non-covalent binding
Specific interaction between the viral attachment protein and the cellular receptor

34
Q

What does attachment determine for viruses?

A

Determines cell and tissue tropism of the virus, and is a major determinant of pathogenesis

35
Q

What does attachment determine for viruses?

A

Determines cell and tissue tropism of the virus, and is a major determinant of pathogenesis

36
Q

What happens when a viral attachment is blocked?

A

Blocking attachment interaction prevents infection, and is a function of neutralizing antibodies

37
Q

Define: Penetration and Uncoating (3)

A

Direct fusion of the viral envelope with the plasma membrane mediated by fusion proteins

Uptake by endocytotic vesicle, change in pH leads to conformational change in envelope glycoproteins exposing fusion peptides

Alteration in the conformation of the capsid, release of the viral genome out of the capsid and transfer through the plasma membrane into the cytoplasm

38
Q

Structure of viral mRNA

A

Single-stranded, positive-sense RNA genome

39
Q

How is viral mRNA transcribed?

A

Transcribed from viral DNA by transcriptase, DNA dependent RNA polymerase (DDPR), either cell in origin, cellular RNA polymerase II, or encoded from the virus

Transcribed from viral negative-sense RNA genomes by viral transcriptase, RNA dependent RNA polymerase (RDRP), which does not exist in eukaryotes

40
Q

How does translation occur in viruses?

A

Cellular ribosomes, tRNAs, and initiating factors attach to viral mRNA via 5’ methyl G cap, internal ribosomal entry sites (IRES), covalently linked viral proteins (VpG)

Viral proteins are translated from an opening reading frame (ORF)

Multiple viral proteins must be produced from a viral genome of limited size

41
Q

How are viral proteins assembled and released?

A

Viral proteins self-assemble or are chaperoned

Genomes are packaged

Virions are released by cell lysis (budding from plasma membrane) or exocytosis after assembly/budding into the ER and Golgi

42
Q

Define: Baltimore Classification

A

System used to classify viruses based on their manner of messenger RNA (mRNA) synthesis

43
Q

DNA viral replication is dependent on what?

A

DNA virus replication is dependent on cellular DNA synthesis and mRNA synthesis in the nucleus

44
Q

What are DNA viral inclusions and where are they located?

A

Accumulations of viral proteins and DNA present in the nucleus of infected cell

45
Q

RNA viral replication is dependent on what?

A

RNA virus replication is dependent on cellular protein synthetic apparatus (translational machinery) in the cytoplasm of the cell

46
Q

What are RNA viral inclusions and where are they located?

A

Accumulations of viral proteins found in the cytoplasm of the infected cell

vm639: virology (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions