Brainscape's Knowledge GenomeTM

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


See full index

FOH Final > 6.8 Medical Virology > Flashcards

6.8 Medical Virology Flashcards

1
Q

What is the minimal requirements for a virus?

A

Minimally a virus has DNA or RNA plus a protein shell called a capsid.

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

What are the functions of the capsid or envelope?

A

1) Protect nucleic acid when extracellular
2) assist in the entry into a new host cell
3) Help package any essential enzymes.

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

What is the most common STD?

A

HPV

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

What are important viruses in the US?

A
  • HPV

- Influenza

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

Describe naked viruses

A
  • Are generally hardy in the environment, can survive well outside host and transmit easily via fecal oral route
  • Examples: Adenovirus, polyomavirusm and calicivirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe enveloped viruses

A
  • Normally take membranes from infected cells to make envelope
  • Are generally sensitive to their environment, easily inactivated by detergents, heat, solvents, and alcohol. Prefer transmission by direct contact or blood
  • Examples: Coronavirus, arenavirus, and orthomyxovirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the Capsid

A
  • Helical or Icosahedral symmetry
  • Viral genomes need to be condensed into the capsid or nucleocapsid
  • Made of many copies of viral proteins
  • Protects the genome and confers shape
  • May interact with cells or immune system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe viral surface structures

A

Used for attachment and penetration, may also be involved in release, maturation, or immunity.

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

Describe Viral Genome

A
  • May be DNA or RNA only
  • Can be single or double stranded
  • May be segmented but normally linear.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three types of RNA genomes?

A

1) Positive sense-Translate straight to mRNA
2) Negative sense- Make positive strand, then make mRNA, must bring own RNA dependent polymerase.
3) Ambisense

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

What must Negitive sense RNA bring in the capsid to infect a cell?

A

RNA dependent polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Are viruses normally diploid or haploid?

A

Mostly haploid, with exceptions such as HIV which is Diploid.

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

What are the 9 steps of viral replication?

A

1) Recognition
2) Attachment
3) Penetration or fuse
4) Uncoating
5) mRNA synthesis
6) Protein synthesis
7) Genome replication
8) Viral processing and building
9) Cell Exit via Lysis or budding

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

Describe viral attachment

A

Randome collision, interaction with host cell receptors, multiple interaction, and fluid nature of plasma membrane

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

Describe Entry of virus via Fusion

A

By fusion of viral envelope with plasma membrane leaves viral spike proteins on the surface for possible cell to cell fusion. Only enveloped viruses.

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

What is viropexis?

A

Viral entry by receptor mediated endocytosis. Naked viruses enter this way

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

What is macropinocytosis?

A

Is a mode of endocytosis in which larger particles are brought into the cell forming an invagination, and then are suspended in small vesicles. These are then fused with lysosomes that help to break down capsid and release viral genome.

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

Describe bacteriophage entry

A

Adsorption, intimate contact, and penetration/uncoating

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

Where do most DNA viruses target?

A
  • The nucleus

- This is so the virus can use the host machinery to make mRNA and then viral proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can double stranded DNA viruses use to yield viral mRNA’s

A

RNA polymerase II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does Hepatitis B virus bring with it when infecting a cell?

A

It is a partially double stranded DNA virus that brings along reverse transcriptase.

22
Q

How do most DNA viruses generate mRNA?

A

Through splicing.

23
Q

Where do most RNA virus stay?

A

In the cytosol

24
Q

What must Retroviruses bring along?

A

Reverse transcriptase.

25
Q

What are examples of virus that have segments that code for one protein?

A
  • Orthomyxovirus (influenza)

- Reoviruses (rotaviruses)

26
Q

What codon initiates mRNA production?

A

AUG

27
Q

What is an example of a latent virus?

A

HPV and Chicken Pox

28
Q

What is an example of a chronic virus?

A

Any of the Hepatitis

29
Q

What causes antigenic drift?

A
  • Mutations in the genome
  • RNA likes to mutate, due to little/no proofreading
  • Host cells can damage genome via oxidation or deamination thus leading to mutation
30
Q

Define Attenuated

A

The disease causing properties are modified to not cause the disease

31
Q

Define Cold-Adapted

A

The virus strains replicate efficiently in cooler areas of the nasopharynx at 25 degrees Celsius, to initiate an immune response in the nose

32
Q

Define Temperature sensitive

A

The virus strains do not replicate in the lungs where infections occurs.

33
Q

What does it mean for a cell to be permissive?

A

The cell must be able to go through replication.
Example:
-Non-permissive CD4 T cells, which make of 95%, infected by HIV are killed before replication can occur.
-Permissive CD4 T cells undergo the full replication cycle of HIV

34
Q

How can defective particles create a functional virus?

A

Defective particles may be complemented with a helper virus. Thus A and B by themselves can not make a functional virus, but if they are together they can.
Example: Delta virus needs HBV to make outer proteins

35
Q

Define Defective interfering (DI) particles

A

May block a productive infection of normal virus by outcompeting for resources in the infected cell.

36
Q

Describe Phenotypic mixing

A

1) Viral genetic diversity via recombination
2) Recombination and template switching
3) Viral genetic diversity via reassortment

37
Q

What are positive effects of recombination?

A
  • Creation of advantageous genotypes
  • Removal of deleterious mutations
  • Repair of defective genomes
38
Q

Describe Antigenic Shift

A
  • Potential for pandemic
  • Is the process by which two or more different strains of a virus, or stains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original stains.
39
Q

Describe Antigenic Drift

A
  • Random Mutations
  • Is a mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody-binding sites
40
Q

What are specimens used for viral diagnosis?

A

Swabs, fluids, scrapings, biopsy, stool.

41
Q

What are indications of viral growth in cell culture?

A
  • Growth of cells in a favorable artificial environment
  • Plaque assay to titer (quantify virus)
  • Virus induced cytopathic effects
  • Visualize cytopathic effect (CPE)
42
Q

What are microscopic methods of identification in the specimen?

A
  • Light microscopy for CPE using biopsied tissues or scrapings
  • Fluorescent antibodies
  • Direct fluorescent antibody test.
  • Electron microscopy: Viruses may be characterized based on morphology and size.
43
Q

What is direct fluorescent antibody test?

A

Virus replicating in tissues/cells is detected using a fluorescently labeled antibody

44
Q

What are serologic procedures to detect a rise in antibody titer or the presence of IgM antibody?

A
  • Enzyme-linked Immunosorbent Assay (ELISA)

- Complement fixation

45
Q

How do you detect viral antigens in blood or body fluids?

A
  • Radioimmunoassy: Sensitive method for detecting antigens, but exposes lab personnel to radioactivity.
  • ELISA “Sandwich: to detect antigens
  • Competitive ELISA for antigens
46
Q

What is Hemagglutinin?

A
  • A viral protein found in the envelope of some viruses that is involved in attachment to respiratory cells; also agglutinates red blood cells of specific animal species in vitro.
  • Species with hemagglutinin: Paramyxoviruses and orthomyxoviruses
47
Q

What is Hemadsorption?

A

-A method for detecting hemagglutinating viruses that is based on adherence of erythrocytes to infected cells.

48
Q

What is a Hemagglutination assay?

A

Hemagglutinin in the viral envelope is detectable by its binding of erythrocytes

49
Q

What is a Hemagglutination inhibition assay?

A

Virus specific antibodies interfere with the interaction between hemagglutinin on the virus and the erythrocyte.

50
Q

What are some methods of detecting viral nucleic acids in blood or in the patients cells?

A
  • DNA probes
  • PCR: Polymerase chan reaction: Exponential amplification of a segment of DNA
  • Reverse transcription- PCR: for RNA templets
  • Real time PCR for qualification (qPCR): uses an internal probe to detect the amplification of the target sequence.

FOH Final (32 decks)

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