Lecture 1

Question 1

The capsid and/or envelope facilitates early aspects of viral infections, including attachment, _____, and release of nucleic acid into the cell (“un-_____.”)

Answer 1

Attachment

Penetration

Un-coating

Question 2

The ______ is the morphological repeating unit of the capsid.

Answer 2

Capsomere

Question 3

_______ are glycoproteins found inserted into viral envelopes that help with attachment and penetration.

Answer 3

Peplomer

Question 4

The _____ layer, found only in enveloped viruses and comprised of _____ proteins, is found between the capsid and the envelope (usually attached to the envelope.)

Answer 4

Matrix

Matrix

Question 5

There are three types of capsid structures:

1. ______ which are typically shaped like icosahedrons.
2. ______ which are typically shaped like cylinders with the nucleic acid bound directly to each of the capsomeres of the capsid.
3. ______ has elements of both of the other 2.

Answer 5

Cubic

Helical

Complex

Question 6

The hierarchichal classification and the associated suffixes of viruses is as follows (in order from broadest to most specific):

1. order - “____”
2. families - “____”
3. subfamilies - “____”
4. genus - “____”
5. species (primary classification.)

Answer 6

order - "Virales"
families - "Viridae"
subfamilies - "virinae"
genus - "viruses"
Species

Question 7

Relatedness, host range, and pathogenicity are the three key features of a virus that allow the ICTV to classify the viral ______. Morphology, genome properties, and strategy of replication/gene expression allow classification down to ______.

Answer 7

Species

Genus

Question 8

______ viral genomes have open reading frames in both positive and negative sense.

Answer 8

Ambisense

Question 9

_____ viruses (type of genome) are a million fold more prone to mutation (frequency of about 10^-3 - 10^-4) because of error-prone polymerases that lack the ability to “_______.”

Answer 9

RNA

Proofread

Question 10

There are 7 families of DNA viruses:

1. _______ (i.e. adenovirus)
2. ______ (i.e. HSV 1+2)
3. ______ (i.e. HPV)
4. ______ (i.e. JCV or BKV)
5. ______ (i.e. mollusca contagiosum, variola, CPX, MPX.)
6. ______ (i.e. parvovirus B19 - “fifth disease”)
7. ______ (i.e. hepatitis B - HBV)

Answer 10

Adenoviridae

Herpesviridae

Papillomaviridae

Polyomaviridae

Poxviriday

Parvoviridae

Hepadnaviridae

Question 11

Embryonaated egg cultures are used when looking for very high _____. Flu, yellow fever, and MM components of MMR are examples of viruses cultured this way. One of the main concerns with production of vaccines from these cultures is ______.

Answer 11

Titres

Allergies

Question 12

Cell culture is another way to obtain virus for study. There are 3 types of cell derivations:

1. ______, which are cells taken from tissue and can only grow for a limited number of _____. Can be mixed cultures.
2. ______, which are derived from normal human tissue (usually fetal and usually clonal) and can be ______.
3. ______ ______, which are typically derived from _____, so they are immortalized and often ______.

Answer 12

Primary

Generations

Diploid

Immortalized

Continuous Lines

Tumors

Aneuploid

Question 13

There are 2 groups of tests done to test for virus:

1. ______ methods, measures the infectious virus, but is time consuming and expensive. It’s typically used for Clinical research and confirming ______.
2. ______ methods, which measure viral components (doesn’t tell you if there’s an infectious virus), are rapid and inexpensive. They’re typically used for clinical research and _______ diagnostics.

Answer 13

Biological

Diagnoses

Physical

Primary

Question 14

All biological methods are based on the ______ effect (change in behavior or appearance of a cell when infected.) Keep in mind that particular viruses will cause particular changes in particular cells (not all cells will react the same to the same virus.)

Answer 14

Cytopathic

Question 15

One of the biological methods is cell _____ used to detect the presence of ______ virus in kidney cells.

Answer 15

Rounding

Vaccinia

Question 16

_____ is another biological method, and it is used to detect _____ virus in lung tumor cells (A___.)

Answer 16

Fusion

Measles

A549

Question 17

______ bodies are another biological method, which shows _____ bodies in neuronal cells (evidence of replicating virus inside cells), and can be used to detect _____.

Answer 17

Inclusion

Negri

Rabies

Question 18

_____ is another biological method used to detect active virus in cells. The idea is the virus will lyse the cells, leaving behind acellular ______. The live cells can be stained, so that acellular ______ would be areas where virus had lysed the cells. Each _____ represents a single infection (telling you the number of viral titres present.)

Answer 18

Lysis

Plaques

Plaques

Plaques

Question 19

Biological methods are sometimes used as a primary diagnostic tool. For instance, newborns born to a mother infected with CMV would have to undergo a cell-based method of detection (biological as opposed to physical/molecular) because the physical method for CMV testing tests for ____. The newborn will be positive regardless of whether he is infected. Why?

Answer 19

Abs

The newborn will be positive for this molecular-based test because he receives all of his Abs from his mother. Thus, a cell-based test should be carried out to determine if the child has an infection.

Question 20

There are 3 types of physical methods for testing:

1. Serological
2. ______
3. Imaging

Answer 20

Molecular

Question 21

The serological testing method is usually _______-based, which uses either an antigen to detect viral Abs, or Abs to detect viral antigen.

Answer 21

ELISA

Question 22

_______ is another form of serological testing that uses _____ _____ ______ (DFAs), which can be used directly on a clinical specimen, so they’re very rapid and cheap. This test has high _____ but low _____ (so positive result is definitive, whereas negative is not.)

Answer 22

Immunofluorescence

Direct Fluorescent Abs

Specificity

Sensitivity

Question 23

_______ inhibition assay is a form of serological testing used to detect viruses of the ______ family (i.e. influenza.) The viral protein that’s tested for binds RBC’s and holds them apart, so a positive test would show diffuse RBCs whereas negative would show a “plug” of RBCs. The inhibition portion of the test adds Abs to _______, which will allow the RBCs to form a “plug.” The idea is to use a bunch of different Abs to determine which strain of virus is present.

Answer 23

Hemagglutinin inhibition assay

Orthomyxoviridae

Hemagglutinin

Question 24

There are 2 techniques used for detection of viral nucleic acid (physical method):

1. __-_______ techniques, which are primarily used to detect _____ virus, include things like in-situ hybrid, southern blot, and hybrid capture.
2. _______ techniques using PCR.

Answer 24

Non-amplification

DNA

Amplification

Question 25

_____ is the last of the physical methods and requires use of an ______ microscope. The particular use for this method is when novel viruses are discovered.

Answer 25

Imaging

Question 26

There are 3 steps all viruses follow in order to enter into a host cell:

1. _____, the binding of the virus to the cell, which is very specific (certain virus on certain cells.)
2. _____, which is when the virus actually enters the host cell via direct fusion (_____ viruses), endocytosis (naked or _____ viruses), or _____ (like the poliovirus entry through an endosome.)
3. _____ –> capsid degenerates to release genetic material.

Answer 26

Adsorption

Penetration

Enveloped

Enveloped

Injection

Uncoating

Question 27

_____, one of the forms of penetration, is pH mediated. As the pH of the endocytic vesicle drops, the capsid undergoes a conformational change that allows it to enter into the cytoplasm for uncoating.

Answer 27

Endocytosis

Question 28

DNA viruses use host _____ to make mRNA. An exception to this is the ______ family –> they don’t move to the nucleus because they bring their own _____.

Answer 28

RNA Pol II

Poxviridae

RNA Pol

Question 29

ssRNA and dsRNA viruses encode their own ______ which translates an ____-sense genome and then generates a sense genome (same as original) for replication.

Answer 29

RNA Pol

Question 30

Gene regulation is important in viral replication. The DNA viruses employ selective _____ usage (late vs early) to accomplish this.

Answer 30

Promoter

Question 31

Positive sense RNA viruses use several strategies for gene regulation:

1. one large ______, which is cleaved by a protease to form the functional proteins. The order of cleavage (post-translational regulation) is what regulates early vs late proteins.
2. Polyproteins made from both genomic and sub-genomic _____.
3. Polyproteins made from genomic mRNA and individual proteins made from _______ mRNA.

Answer 31

Polyprotein

mRNA

Sub-genomic

Question 32

Negative sense RNA viruses produce all individual proteins from multiple _____ _____ frames. The idea is that the early phase proteins would be encoded closest to the _____ end, so they can accumulate faster.

Answer 32

Open Reading frames

3’ end

Question 33

Some viruses have specific packaging sequences (____ sequences) that directly bind capsid protein to facilitate capsid formation around the genome.

Answer 33

Psi sequences

Question 34

Non-enveloped viruses escape cells via ____, while enveloped viruses bud through either the _____ (subsequently released via exocytosis) or plasma membrane.

Answer 34

Lysis

Golgi

Question 35

______ is the most prevalent cause of immunodeficiency in children worldwide, with _____ being the number one killer of these children.

Answer 35

Malnutrition

Measles

Question 36

______ is a mode of transmission that occurs in a ______ or healthcare facility. _____ is an infection directly by a healthcare worker.

Answer 36

Nosocomial

hospital

Iatrogenic

Question 37

_____ transmission, a type of human-human transmission, occurs between mother an offspring immediately before, during, or after birth.

Answer 37

Vertical

Question 38

The difference between localized and disseminated infections is the side of cells through which the virus exits. In both cases, the virus enters via the ____ surface, but virus exits through the _____ surface in disseminated infection.

Answer 38

Apical

Basolateral