Term
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Definition
| a package of genetic information protected by a protein shell for delivery into a host cell to be expressed and replicated |
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Term
| Virus is from the greek meaning ___ |
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Definition
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Term
| There is a debate about whether viruses are ___. |
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Definition
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Term
| Name the characteristics that differentiate viruses form other microorganisms. |
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Definition
1. Nucleic acid (one of either DNA or RA)
2. Lack of nuclear membrane and external cell wall
3. Very small genomes that produce limited numbers of proteins and do not posses intracellular systems |
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Term
| What evidence do we have of early viral disease? |
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Definition
- pock marks indicative of smallpox
- 1500 BC - leg deformities in hieroglyphics indicative of polio |
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Term
Give examples of viral diseases for the following time scales:
1000 years
100 years
10 years |
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Definition
1000 --> smallpox and measles
100 --> spanish influenza, HIV
10 --> SARS, MERS, Avian flu, H1N1, Ebola |
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Term
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Definition
| Not really, it's been around for about 20 years but haven't seen an outbreak like this one |
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Term
| How do we classify viruses? |
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Definition
- Disease they are associated with
- Cyto-Pathology they cause
- Site of isolation (ex: adenovirus, enterovirus)
- Places or people that discovered them (ex: Epstein Barr virus or West Nile)
- Biochemical features (ex: retrovirus... goes from RNA to DNA) |
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Term
| Viral taxonomy is usually based on ... (4) |
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Definition
1. Type and form of nucleic acid
2. Structure
3. The organization of the genome
4. Antigenic differences |
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Term
| Explain the possible viral nucleic acid for RNA viruses |
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Definition
They can be be RNA single stranded with positive or negative polarity.
OR
They can be RNA double stranded with one piece or segmented |
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Term
| Explain the possible viral nucleic acid for DNA viruses |
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Definition
| single or double stranded |
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Term
| What does positive sense mean? |
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Definition
| it means that it is similar to mRNA so it can be immediately translated by the host cell |
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Term
| What does negative sense mean? |
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Definition
| Negative-sense viral RNA is complementary to mRNA and thus must be converted to + sense by an RNA polymerase before translation |
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Term
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Definition
- Capsomeres are structural subunits containing several proteins
- they aggregate to produce the viral capsid |
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Term
| What does the viral capsid do? |
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Definition
| It associates with the viral nucleic acid to produce a nucleocapsid |
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Term
| How are nucleocapsids usually arranged? |
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Definition
- cubic (ex: herpes)
- helical (ex: influenza)
- complex |
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Term
| Where are lipid envelopes of viruses derived from? |
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Definition
cellular membranes!
Could be the external cell membrane or organelle membranes (such as the golgi or ER) |
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Term
| Viral envelopes are studded with surface projections called __ or __. |
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Definition
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Term
| Surface projects of viral envelopes are usually ___ by __ __ to make them sticky. |
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Definition
| glycosylated by host systems |
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Term
| Which type of viruses, naked or enveloped, tend to survive longer in the environment? |
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Definition
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Term
| Of the icosahedral DNA type viruses, which ones are naked and which ones are enveloped? |
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Definition
Naked: papilloma virus, parvovirus, adenovirus
Enveloped: herpes virus and hepatitis |
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Term
| Of the icosahedral DNA type viruses, which ones are naked and which ones are enveloped? |
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Definition
Naked: papilloma virus, parvovirus, adenovirus
Enveloped: herpes virus and hepatitis |
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Term
| What is an example of a complex DNA virus? |
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Definition
| Pox viruses! They can carry a lot of genetic material |
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Term
| HIV is a ___. It is (naked/enveloped). It is (icosahedral/helical) |
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Definition
retrovirus
envelopeed
icosahedral |
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Term
| Hepatitis C is a ___. It is (naked/enveloped). It is (icosahedral/helical) |
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Definition
flavivirus
enveloped
icosahedral |
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Term
| Coxsackie viruses, echo virus and polio virus are all examples of ___. |
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Definition
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Term
| Name the 3 RNA viruses that are Icosahedral, Naked, Picornaviruses! |
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Definition
1. Enteroviruses
2. Rhinoviruses
Hepatitis A |
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Term
| Give examples of RNA viruses that are helical and enveloped |
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Definition
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Term
| How are viruses acquired? (DAPFVVE) |
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Definition
- Direct personal contact
- Airborne spread
- Parenterally
- Fomites
- Vectors
- Vertical Transmission
- Enteral |
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Term
| Give examples of viruses acquired through direct personal contact |
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Definition
Herpes (mucosal spread)
HIV (mucosal spread)
Influenza (droplet) |
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Term
| Give examples of viruses acquired through airborne spread |
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Definition
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Term
| Give examples of viruses acquired through parenteral spread |
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Definition
HIV
Hep B & C
Cytomegalovirus |
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Term
| Give examples of viruses acquired through fomites |
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Definition
| enteroviruses and other sturdy drying resistant viruses |
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Term
| Give examples of viruses acquired through vectors |
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Definition
West Nile
- this involves an intermediary such as a bug or animal that transmits the infection |
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Term
| Give examples of viruses acquired through vertical transmission |
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Definition
HIV
Herpes simplex
Cytomegalovirus
Rubella |
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Term
| Give examples of viruses acquired through enteral (food borne) transmission |
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Definition
Hep A
gastroenteritis viruses |
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Term
| List the 5 basic steps that a virus takes to infect |
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Definition
1. Attachment (recognize cell, attach and get in)
2. Uncoating
3. Replication
4. Assembly
5. Egress |
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Term
| What are some consequences of viruses interacting with cells? |
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Definition
- Viral proliferation and cell lysis
- Latent infection
- Persistent infection
- Oncogenesis
- No apparent disease |
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Term
| How do you diagnose a viral infection (lab diagnosis)? |
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Definition
- histology and cytology
- direct examination by electron microscopy
- examination looking for viral antigens (in tissue or serum(
- antibody testing
- virus isolation
- DNA or RNA amplification |
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Term
| What the heck is a prion?! |
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Definition
- A proteinaceous infectious particle
- aka an infectious agent that is composed of protein (no genetic material) |
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Term
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Definition
| Instead of self replicating they induce existing proteins to look like them (take on a rogue form) |
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Term
| Prions are highly resistant to ___ and __ |
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Definition
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Term
| Give both a human and animal form example of the spongiform encephalopathies that prions cause |
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Definition
Human = Creutzfeldt-Jacob Disease
animal = bovine spongiform encephalopathy |
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