Term
| About how many genes does a small virus have? A large virus? |
|
Definition
|
|
Term
| What do viruses consist of? |
|
Definition
| A nucleic acid surrounded by a protein coat (a capsid) |
|
|
Term
Which of the characteristics of viral nucleic that are true:
Can be both DNA or RNA
Double or single stranded
Circular- cannot be linear
Only comes in segments
A matrix protein can surround the nucleic acid |
|
Definition
|
|
Term
| What is the virus capsid made up of ? |
|
Definition
| Made of protein subunits called capsomeres which fit together into a hollow shell |
|
|
Term
| What is the most common structures of a virus? |
|
Definition
| An ocosahedron- 20 triangular faces |
|
|
Term
| What are other common structures of a virus? |
|
Definition
| Polyhedral, helical, complex |
|
|
Term
| Some viruses have an outer membrane called _______________. |
|
Definition
|
|
Term
| Where does the virus envelope come from? |
|
Definition
| Comes from the host cell membrane. |
|
|
Term
| True or False: The viruses envelope contains only viral proteins and glycoproteins in it. |
|
Definition
| False, it can have both host and viral |
|
|
Term
| Why are these proteins important? |
|
Definition
| These proteins are important because they can mediate adherence of the virus to the host, and can be antigenic (recognized as foreign by the host) and serve as vaccines. |
|
|
Term
| What part of a viruses structure attaches to receptors on the host and allow for infection? |
|
Definition
|
|
Term
| How many families of human viruses are there? |
|
Definition
| 22- all ending with "viridae" |
|
|
Term
| What five features organize viral classification? |
|
Definition
1. Nature of nucleic acid- RNA or DNA
2. Single-stranded or double-stranded nucleic acid
3. Capsid shape- polyhedral, helical, both
4. Presence or absence of an envelope
5. Size of virion |
|
|
Term
| How many families of DNA viruses currently exist? How many families of RNA viruses currently exist? |
|
Definition
|
|
Term
| How are viral classification based on route of transmission grouped? |
|
Definition
| Often grouped according to their route of transmission or organ system they infect |
|
|
Term
| How do enteric viruses spread and infect? |
|
Definition
| Spread by the fecal-oral route, infect the GI tract |
|
|
Term
| How do respiratory viruses spread and infect? |
|
Definition
| Spread by respiratory route, infect through the respiratory tract |
|
|
Term
| How do sexually transmitted viruses spread and infect? |
|
Definition
| Spread through sexual transmission, infect through genital tract |
|
|
Term
| What are zoonotic viruses? |
|
Definition
| Animal viruses that can infect humans |
|
|
Term
|
Definition
| Arthropod-borne, insect viruses that can infect humans. |
|
|
Term
| What does the virus genome contain? |
|
Definition
| Only a few genes needed to make it capsomeres, replicate its nucleic acid, and get out of the host cell |
|
|
Term
| True or False: Viruses use host enzymes, ribosomes, and molecules to replicate |
|
Definition
|
|
Term
| Explain the two-stage life cycle of viruses |
|
Definition
1. Outside the host cell they are inert- virions
2. Inside the host cell they replicate themselves or to persist in a latent state until they begin replicating |
|
|
Term
| What is balanced pathogenicity? |
|
Definition
| The virus may hurt the host a little but not enough to kill the host or reduce its ability to transmit the virus |
|
|
Term
| What is a productive infection? |
|
Definition
| A virus that immediately invades, replicates, and kills their host cell |
|
|
Term
| What do latent viruses do? |
|
Definition
| Viruses that integrate their chromosome into the host and stay latent until activated |
|
|
Term
| What is a persistent infection |
|
Definition
| Viruses replicate slowly and continue to produce new viruses without immediately killing the host |
|
|
Term
| What are the steps in productive viral infections? |
|
Definition
1. Attachment
2. Entry
3. Targeting
4. Uncoating of the virion
5 Viral DNA is transcribed, replicated and translated to make new viruses
6. New virions assemble or mature spontaneously
7. New viruses are released from the cell |
|
|
Term
| True or False: Viruses have a low host-range specificity for host species and organ tissues with the species |
|
Definition
|
|
Term
| In bacteriophages, viral DNA is |
|
Definition
|
|
Term
| In animal viruses, the whole virus |
|
Definition
|
|
Term
| How do enveloped viruses enter its host? |
|
Definition
| They fuse their membranes |
|
|
Term
| Where can targeting occur? |
|
Definition
| Can be the cell cytoplasm or nucleus |
|
|
Term
| Where do most DNA viruses replicate? |
|
Definition
| In the cell nucleus because that is where the deoxyribonucleotides and replication enzymes are |
|
|
Term
| What are the steps of uncoating of the virion? |
|
Definition
1. The capsomeres open and release the nucleic acid for it to be replicated by the host cell's enzymes
2. Capsomeres are held together by weak hydrogen bonds |
|
|
Term
| What do the first enzymes do in viral DNA? |
|
Definition
| Destroy the host genome to stop the cell from replicating |
|
|
Term
| What do later enzymes do? |
|
Definition
| Replicate the viral genome and produce viral capsomeres |
|
|
Term
| True or False: Host metabolism continues, providing energy and components for the virus |
|
Definition
|
|
Term
| What are the two types of acute viral infections? |
|
Definition
1. Acute
2. Acute with noninfectious sequellae |
|
|
Term
| What are the two types of persistent viral infections? |
|
Definition
|
|
Term
| What are the types of viral infections? |
|
Definition
1. Slow viruses
2. Prions
3. Retrovirus |
|
|
Term
| What are the characteristics of a slow virus? |
|
Definition
| -Following a mild or subclinical acute infection, the virus gradually increases its replication and pathology over months, years, or decades |
|
|
Term
| What are prions and what are their characteristics? |
|
Definition
| Prions are infectious agents that we associate with protein sequences but no nucleic acids. They cause CNS disease in animal and humans |
|
|
Term
| What are the characteristics of a Retrovirus? |
|
Definition
1. Named for an enzyme, reverse transcriptase
2. Causes acquired immunodeficiency syndrome (AIDS) in humans
3. The entire virus genome is translated as one protein, the cleaved by a protease
4. Anti-HIV drugs are inhibitors of the viral protease |
|
|
Term
|
Definition
| When DNA viruses become latent and integrate their DNA into the genes of humans, they can transform the cells and cause uncontrolled growth. |
|
|
Term
| What type of virus prefers stability |
|
Definition
|
|
Term
| What type of virus prefers instability? |
|
Definition
| If the virus needs to stay ahead of the host immune system, instability may be good because the virus can change before the immune system catches up |
|
|
Term
| What are cells in living host tissues separated with? |
|
Definition
|
|
Term
| What is contact inhibition? |
|
Definition
| When cells divided until they touch, then stop |
|
|
Term
| How do you passage a flask that is full? |
|
Definition
| Remove the cells trypsin, dilute them, feed them, and put them in a new flask or tube |
|
|
Term
| What are primary cell cultures? |
|
Definition
| The cells made directly from the tissues |
|
|
Term
|
Definition
| Cell lines that keep dividing |
|
|
Term
| What are the advantages of using culture? |
|
Definition
1. Culture of the virus from the specimen is the definitive way to diagnose a viral infection
2. You can do further tests to characterize it and save it |
|
|
Term
| What are the disadvantages of culture? |
|
Definition
1. Cultures take a long time and cost a lot
2. Requires a separate lab
3. Requires a lot of skill and equipment |
|
|
Term
| What is Direct Flourescent Antibody (DFA) testing? |
|
Definition
1. Detects virus- specific antigens on the host cell
2. Take the direct specimen with infected cells it in, put them on a microscope slide, stain
3. If the cell lights up, they are infected |
|
|
Term
| What does an amplified nucleic acid test detect? |
|
Definition
| Specific segments of the virus nucleic acid. |
|
|
Term
| What are the advantages of PCR? |
|
Definition
1. Sensitivity; can detect one copy of the virus
2. Specificity; if you chose your primers well
3. Can be fast; 2-3 hours |
|
|
Term
| What are the disadvantages of molecular tests? |
|
Definition
1. Can't tell live from dead virus
2. Useless for persistent viruses; it is always there |
|
|
Term
| How do sexually transmitted viruses spread and infect? |
|
Definition
| Spread through sexual transmission, infect through genital tract |
|
|
Term
| What are zoonotic viruses? |
|
Definition
| Animal viruses that can infect humans |
|
|
Term
|
Definition
| Arthropod-borne, insect viruses that can infect humans. |
|
|
Term
| What does the virus genome contain? |
|
Definition
| Only a few genes needed to make it capsomeres, replicate its nucleic acid, and get out of the host cell |
|
|
Term
| True or False: Viruses use host enzymes, ribosomes, and molecules to replicate |
|
Definition
|
|
Term
| Explain the two-stage life cycle of viruses |
|
Definition
1. Outside the host cell they are inert- virions
2. Inside the host cell they replicate themselves or to persist in a latent state until they begin replicating |
|
|
Term
| What is balanced pathogenicity? |
|
Definition
| The virus may hurt the host a little but not enough to kill the host or reduce its ability to transmit the virus |
|
|
Term
| What is a productive infection? |
|
Definition
| A virus that immediately invades, replicates, and kills their host cell |
|
|
Term
| What do latent viruses do? |
|
Definition
| Viruses that integrate their chromosome into the host and stay latent until activated |
|
|
Term
| What is a persistent infection |
|
Definition
| Viruses replicate slowly and continue to produce new viruses without immediately killing the host |
|
|
Term
| What are the steps in productive viral infections? |
|
Definition
1. Attachment
2. Entry
3. Targeting
4. Uncoating of the virion
5 Viral DNA is transcribed, replicated and translated to make new viruses
6. New virions assemble or mature spontaneously
7. New viruses are released from the cell |
|
|
Term
| True or False: Viruses have a low host-range specificity for host species and organ tissues with the species |
|
Definition
|
|
Term
| In bacteriophages, viral DNA is |
|
Definition
|
|
Term
| In animal viruses, the whole virus |
|
Definition
|
|
Term
| How do enveloped viruses enter its host? |
|
Definition
| They fuse their membranes |
|
|
Term
| Where can targeting occur? |
|
Definition
| Can be the cell cytoplasm or nucleus |
|
|
Term
| Where do most DNA viruses replicate? |
|
Definition
| In the cell nucleus because that is where the deoxyribonucleotides and replication enzymes are |
|
|
Term
| What are the steps of uncoating of the virion? |
|
Definition
1. The capsomeres open and release the nucleic acid for it to be replicated by the host cell's enzymes
2. Capsomeres are held together by weak hydrogen bonds |
|
|
Term
| What do the first enzymes do in viral DNA? |
|
Definition
| Destroy the host genome to stop the cell from replicating |
|
|
Term
| What do later enzymes do? |
|
Definition
| Replicate the viral genome and produce viral capsomeres |
|
|
Term
| True or False: Host metabolism continues, providing energy and components for the virus |
|
Definition
|
|
Term
| What are the two types of acute viral infections? |
|
Definition
1. Acute
2. Acute with noninfectious sequellae |
|
|
Term
| What are the two types of persistent viral infections? |
|
Definition
|
|
Term
| What are the types of viral infections? |
|
Definition
1. Slow viruses
2. Prions
3. Retrovirus |
|
|
Term
| What are the characteristics of a slow virus? |
|
Definition
| -Following a mild or subclinical acute infection, the virus gradually increases its replication and pathology over months, years, or decades |
|
|
Term
| What are prions and what are their characteristics? |
|
Definition
| Prions are infectious agents that we associate with protein sequences but no nucleic acids. They cause CNS disease in animal and humans |
|
|
Term
| What are the characteristics of a Retrovirus? |
|
Definition
1. Named for an enzyme, reverse transcriptase
2. Causes acquired immunodeficiency syndrome (AIDS) in humans
3. The entire virus genome is translated as one protein, the cleaved by a protease
4. Anti-HIV drugs are inhibitors of the viral protease |
|
|
Term
|
Definition
| When DNA viruses become latent and integrate their DNA into the genes of humans, they can transform the cells and cause uncontrolled growth. |
|
|
Term
| What type of virus prefers stability |
|
Definition
|
|
Term
| What type of virus prefers instability? |
|
Definition
| If the virus needs to stay ahead of the host immune system, instability may be good because the virus can change before the immune system catches up |
|
|
Term
| What are cells in living host tissues separated with? |
|
Definition
|
|
Term
| What is contact inhibition? |
|
Definition
| When cells divided until they touch, then stop |
|
|
Term
| How do you passage a flask that is full? |
|
Definition
| Remove the cells trypsin, dilute them, feed them, and put them in a new flask or tube |
|
|
Term
| What are primary cell cultures? |
|
Definition
| The cells made directly from the tissues |
|
|
Term
|
Definition
| Cell lines that keep dividing |
|
|
Term
| What are the advantages of using culture? |
|
Definition
1. Culture of the virus from the specimen is the definitive way to diagnose a viral infection
2. You can do further tests to characterize it and save it |
|
|
Term
| What are the disadvantages of culture? |
|
Definition
1. Cultures take a long time and cost a lot
2. Requires a separate lab
3. Requires a lot of skill and equipment |
|
|
Term
| What is Direct Flourescent Antibody (DFA) testing? |
|
Definition
1. Detects virus- specific antigens on the host cell
2. Take the direct specimen with infected cells it in, put them on a microscope slide, stain
3. If the cell lights up, they are infected |
|
|
Term
| What does an amplified nucleic acid test detect? |
|
Definition
| Specific segments of the virus nucleic acid. |
|
|
Term
| What are the advantages of PCR? |
|
Definition
1. Sensitivity; can detect one copy of the virus
2. Specificity; if you chose your primers well
3. Can be fast; 2-3 hours |
|
|
Term
| What are the disadvantages of molecular tests? |
|
Definition
1. Can't tell live from dead virus
2. Useless for persistent viruses; it is always there |
|
|
