Term
| What complexes of nucleic acids and proteins that have the capacity for replication in animal, plant, and bacterial cells? |
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Definition
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Term
| How to viruses replicate? |
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Definition
| Take over functions of host cell which they parasatize |
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Term
| Characteristics of a virus include...(5 things) |
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Definition
1. Microscopic particle that can infect the cells of a wide variety of organisms
2. Cannot replicate by themselves; replicate only by infecting a host cell
3. Basic structure consists of genetic material contained within a protective protein coat (capsid)
4. Possess genes and can evolve by natural selection
5. Unlike most other forms of life that use cell division to reproduce, viruses spontaneously assemble themselves within cells |
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Term
What type of infection has...
Entry into permissive cells is followed by virion formation |
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Definition
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Term
What type of infection has...
Entry into a non-permissive cell does not result in virion formation |
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Definition
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Term
What type of infection has...
Cell is transiently permissive and only a few viruses are produced; while virus production stops but the genome remains present in the cell |
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Definition
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Term
| Viruses consist of genetic material contained within a protective protein coat called... |
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Definition
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Term
| A complete virus particle is called a _____ and consists of nucleic acid (DNA or RNA) surrounded by a protective protein coat. |
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Definition
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Term
| Do viruses posses genes, but they can not evolve. |
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Definition
| Yes and no cause they can evolve |
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Term
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Definition
| creating multiple copies of themselves but require a host cell to replicate and synthesize new proteins |
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Term
| While most cells use cell division to reproduce, what to viruses do? |
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Definition
| spontaneously assemble themselves within cell |
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Term
Outcomes of virus-cell interactions, this is considered?
cell possess appropriate receptors for virus, as well as all machinery necessary for viral genome replication and infectious virion release |
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Definition
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Term
Outcomes of virus-cell interactions, this is considered?
cell lacks appropriate receptor for virus and therefore cannot interact with virion |
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Definition
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Term
Outcomes of virus-cell interactions, this is considered?
entry into a cell does not result in virion formation because insufficient viral DNA/RNA may be produced or non-infectious virions are produced |
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Definition
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Term
Outcomes of virus-cell interactions, this is considered?
the cell is transiently permissive and only a few viruses are produced; thereafter, virus production stops but the genome remains present in the cell |
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Definition
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Term
| Once a virus becomes restrictive, is the scare over? |
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Definition
| No, may still have serious consequences such as cell transformation and/or cancer |
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Term
| What are some examples of viruses that are Restrictive? |
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Definition
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Term
| lipid bilayers surrounding the virus capsid |
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Definition
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Term
| No envelope = nucleocapsid only = |
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Definition
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Term
| The envelope is typically derived from? |
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Definition
| the host cell membranes (phospholipids and proteins) |
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Term
| Proteins in the envelope can be from which two sources? |
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Definition
-host cell
-viral proteins |
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Term
| Enveloped viruses are ______ to sterilize than non-enveloped viruses and have _______ survival outside host environments |
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Definition
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Term
| IN what form can the genetic information be stored in viruses? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
| For RNA viruses, proofreading mechanism doesn't exist, but or body cells does the proofreading and slightly changes the virus in every person. This thought is known as? |
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Definition
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Term
| Can you classify a virus based on its structures and some of its function? |
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Definition
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Term
| In terms of structure viruses are? |
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Definition
| Very repetitive and ordered |
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Term
| Based on viral proteins in the envelope, they are sensitive to? |
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Definition
-Dessication
-Heat
-Detergents(in lab if spill, put bleach and they dont survive) |
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Term
| For enveloped viruses, the virion is complete – or infectious – even before the envelope is acquired |
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Definition
| False, not complete and infectious til then |
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Term
| Envelopes help viruses enter host cells by identifying and binding host cell receptors? T/F |
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Definition
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Term
| Central dogma of molecular biology: |
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Definition
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Term
| All viruses must make viral proteins that: |
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Definition
-ensure replication of the viral genome
-package the genome into virus particles (virions)
-alter the metabolism of the infected cell so that viruses are produced |
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Term
| At the end of the day, no matter what type of Genomic taxonomy you have, you must get to... |
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Definition
| mRNA in order to make protein |
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Term
| What is the basic life cycle? |
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Definition
1) Attachment of virion to a receptor(always needed)
2) Penetration
3) Uncoating (genome is released into cell)
4) Biosynthesis (genome replication and protein synthesis)
5) Assembly
6) Release (lytic or budding processes) |
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Term
| What are the four Penetration methods of virions? |
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Definition
1) Direct fusion at the plasma membrane (enveloped viruses only)
2) Receptor-mediated endocytosis (or macropinocytosis)
3) Pore-mediated penetration
4) Cell-to-cell movement (non-enveloped viruses) |
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Term
| Is there just one receptor for viruses, multiple or none? |
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Definition
| one or multiple never ever is there none |
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Term
| Receptors can determine what two aspects of viruses? |
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Definition
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Term
| What are 3 main reasons for having a capside? |
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Definition
1)Physical environment is hostile
–UV is damaging
2) Nucleic acids are fragile
–Shearing of viral genome can happen
-Cellular enzymes are damaging
-pH can be damaging
3) Protein coat can facilitate viral entry (specific for non-envelope or naked virions) |
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Term
| After uncoating, the viral genome is replicated in which two places possibly? |
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Definition
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Term
| If a virus is replicated in the cytoplasm, where type are they? |
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Definition
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Term
| If a virus is replicated in the nucleus, where type are they? |
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Definition
| All DNA viruses except poxvirus |
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Term
| ssDNA is subject to what problem? |
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Definition
| degradation (better to be dsDNS virus) |
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Term
| Herpes is what type of virus in terms of genetic material? |
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Definition
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Term
| What do RNA viruses require and is a target for drug? |
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Definition
RNA-dependent RNA polymerases that are not encoded by host cells
-either has to be carried or made right away |
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Term
| Viruses can be classified based on morphology? |
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Definition
-Size
-Shape
-Enveloped
-Uneveloped |
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Term
| Viruses can be classified based on genome? |
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Definition
-RNA/DNA
-linear/circular/segmented
-single/double-stranded
-positve/negative-sense |
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Term
| Viruses can be classified based on Physiochemical Properties? |
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Definition
-Molecular mass
-Buoyant density
-pH
-thermal
-ionic stability |
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Term
| Viruses can be classified based on type of host? |
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Definition
-algae
-archaea
-fungi
-plants
-vertebraes, etc |
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Term
| Viruses can be classified based on Biological properties? |
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Definition
-host range
-mode(s) of transmission
-tropism (growth, turnover of an organism) |
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Term
T/F
All viral protein synthesis is completely dependent upon the translational machinery of the cell as no viral genomes encode a complete system for translating proteins |
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Definition
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Term
| For a virus to multiply, it must... |
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Definition
| infect a cell (it can not replicate outside the cell on its own) |
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Term
| Can viruses infect any species? |
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Definition
| No, Viruses usually have a restricted host range (i.e. a particular animal and a particular cell type) in which they multiply/replicate |
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Term
| The Viral taxonomy includes... |
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Definition
I: Double-stranded DNA
Adenoviruses; Herpesviruses; Poxviruses
II: Single-stranded (+) sense DNA
Parvoviruses
III: Double-stranded RNA
Reoviruses
IV: Single-stranded (+) sense RNA
Picornaviruses; Togaviruses
V: Single-stranded (-) sense RNA
Orthomyxoviruses, Rhabdoviruses
VI: Single-stranded (+) sense RNA with DNA intermediate
Retroviruses
VII: Double-stranded DNA with RNA intermediate
Hepadnaviruses |
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Term
| Attachment of a virus to a receptor (3 keys)... |
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Definition
-More than one receptor may be utilized per virus
-Keep in mind that receptor(s) may not have been discovered yet
-Determines cell tropism and host range |
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Term
| Enveloped virion enters host via? |
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Definition
-Fusion at plasma membrane
-Endocytosis |
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Term
| Unenveloped virion enters host via? |
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Definition
| Pore mediated penetration |
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Term
| Viral uncoating can happen in which two ways? |
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Definition
-Simultaneously with entry
-Involving a series of ordered steps after attachment and penetration of virions |
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Term
| Releases viral RNA/DNA into cell via, which ways? |
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Definition
-Fusion (via ER)
-Permeabilization
-Lysis (bursting of capsid) |
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Term
| DNA viruses think ReDIAL, what does this stand for? |
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Definition
-Re Replicate in nucleus
-D Double-stranded
-I Icohedral structures
-A Enveloped
-L Linear Genomes |
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Term
| What are the two basic types of RNA viruses? |
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Definition
1) Viruses that copy their RNA into new RNA without a DNA intermediate
2) Viruses that use a DNA intermediate |
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Term
| What are some types of Viruses that copy their RNA into new RNA without a DNA intermediate? |
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Definition
Positive-strand RNA viruses (e.g. picornaviruses)
Negative-strand RNA viruses (e.g. influenza)
Double-stranded RNA viruses (e.g. rotaviruses) |
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Term
| What is an example of Viruses that use a DNA intermediate? |
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Definition
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Term
| RNA viruses require what? |
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Definition
| RNA-dependent RNA polymerases that are not encoded by host cells |
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Term
| Where do RNA viruses get these polymerases? |
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Definition
-transport into cell at time of infection
-synthesize them soon after infection |
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Term
| What should I be aware of for RNA viruses in terms of mutations? |
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Definition
| These enzymes(RNA polymerases) lack proof-reading/editing ability; therefore, RNA viruses typically mutate more quickly than DNA viruses |
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Term
| What mediates cap-independent internal initiation of translation by recruiting multiple cellular and viral proteins? |
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Definition
| 5’ untranslated region (UTR) contains the internal ribosome entry site (IRES) |
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Term
| What does ReSHEL stand for in RNA viruses? |
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Definition
-Re Replicate in the cytoplasm
-S Single-stranded
-H Helical structures
-E Enveloped
-L Linear genomes |
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Term
| Virion assembly can occur by what 3 mechanisms? |
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Definition
1) Spontaneously (self-assembly)
2) Require specific virus-encoded proteins (scaffolding proteins) which do not ultimately form part of the virion structure
3) Be assembled from pre-cursor proteins which are modified to form infectious virions |
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