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Virus attachment is the binding of the virus to the host ______.
Virus attachment is the binding of the virus to the host ______.
cell
Rhinovirus binds a protein known as ______ 1 (ICAM-1).
Rhinovirus binds a protein known as ______ 1 (ICAM-1).
intercellular adhesion molecule
Influenza A virus strains bind to the ______ acid sugars found at the ends of cellular carbohydrate chains.
Influenza A virus strains bind to the ______ acid sugars found at the ends of cellular carbohydrate chains.
sialic
HIV initially binds to a protein known as ______ on the surface of T lymphocytes with one of two coreceptor proteins.
HIV initially binds to a protein known as ______ on the surface of T lymphocytes with one of two coreceptor proteins.
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The Baltimore classification system categorizes viruses based on the type of ______ acid genome and replication strategy of the virus.
The Baltimore classification system categorizes viruses based on the type of ______ acid genome and replication strategy of the virus.
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Poliovirus binds to the ______ receptor (PVR) CD155.
Poliovirus binds to the ______ receptor (PVR) CD155.
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Measles virus binds to ______, CD150.
Measles virus binds to ______, CD150.
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Positive-strand RNA is able to be immediately translated into ______.
Positive-strand RNA is able to be immediately translated into ______.
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Dengue virus binds to ______.
Dengue virus binds to ______.
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Viruses are only classified using ______, family, genus, and species.
Viruses are only classified using ______, family, genus, and species.
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The ______ of a virus is generally the “common name” of the virus.
The ______ of a virus is generally the “common name” of the virus.
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Most types of viruses use ______-mediated endocytosis to enter the cell.
Most types of viruses use ______-mediated endocytosis to enter the cell.
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The suffix -virales is used in the ______ of viruses.
The suffix -virales is used in the ______ of viruses.
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Negative-strand RNA is not translatable into ______; it first has to be transcribed into positive-strand RNA.
Negative-strand RNA is not translatable into ______; it first has to be transcribed into positive-strand RNA.
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The genus of a virus ends in the suffix -______.
The genus of a virus ends in the suffix -______.
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The family of a virus ends in the suffix -______.
The family of a virus ends in the suffix -______.
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The virus's genome acts as the instructions for the synthesis of virus ______.
The virus's genome acts as the instructions for the synthesis of virus ______.
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The replication strategy of a virus is generally dependent upon the type of ______ acid genome it contains.
The replication strategy of a virus is generally dependent upon the type of ______ acid genome it contains.
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Viruses with ______ genomes have similar nucleic acid to living organisms and often use the enzymes and proteins that the cell normally uses.
Viruses with ______ genomes have similar nucleic acid to living organisms and often use the enzymes and proteins that the cell normally uses.
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The Baltimore classification system categorizes the viruses into seven classes based upon their type of ______.
The Baltimore classification system categorizes the viruses into seven classes based upon their type of ______.
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The ______ polymerases are used by viruses with dsDNA genomes.
The ______ polymerases are used by viruses with dsDNA genomes.
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The ______ viruses are classified into Class I according to the Baltimore classification system.
The ______ viruses are classified into Class I according to the Baltimore classification system.
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The ______ viruses are classified into Class IV according to the Baltimore classification system.
The ______ viruses are classified into Class IV according to the Baltimore classification system.
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The ______ virus is an example of a virus that reverse transcribes.
The ______ virus is an example of a virus that reverse transcribes.
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So all dsDNA viruses that infect humans enter the nucleus of the cell, while ______ genomes do not.
So all dsDNA viruses that infect humans enter the nucleus of the cell, while ______ genomes do not.
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During replication, the ssDNA genome enters the nucleus of the host cell, where the ssDNA is converted to dsDNA by ______ polymerase.
During replication, the ssDNA genome enters the nucleus of the host cell, where the ssDNA is converted to dsDNA by ______ polymerase.
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DsRNA viruses contain an ______ that is carried into the cell within the virion.
DsRNA viruses contain an ______ that is carried into the cell within the virion.
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The genomes of +ssRNA viruses are infectious, since positive-sense RNA is able to be directly translated by ______.
The genomes of +ssRNA viruses are infectious, since positive-sense RNA is able to be directly translated by ______.
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−ssRNA viruses are not infectious and must be transcribed into ______ before translation can occur.
−ssRNA viruses are not infectious and must be transcribed into ______ before translation can occur.
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Retroviruses are viruses that reverse transcribe an RNA genome into ______.
Retroviruses are viruses that reverse transcribe an RNA genome into ______.
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RNA polymerase II transcribes an RNA pregenome that is reverse transcribed, after being packaged into the capsid, into the rcDNA genome in the ______ of the cell.
RNA polymerase II transcribes an RNA pregenome that is reverse transcribed, after being packaged into the capsid, into the rcDNA genome in the ______ of the cell.
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New strains of virus can occur when two different strains infect one ______.
New strains of virus can occur when two different strains infect one ______.
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Recombination occurs when the genome of an RNA virus is being replicated and the RdRp jumps from the template of one strain to the template of the other strain, creating a hybrid ______.
Recombination occurs when the genome of an RNA virus is being replicated and the RdRp jumps from the template of one strain to the template of the other strain, creating a hybrid ______.
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Reassortment occurs when the genome segments of ______ viruses are mixed while being packaged into new capsids.
Reassortment occurs when the genome segments of ______ viruses are mixed while being packaged into new capsids.
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Viruses components must be collected at a particular site of the cell and undergo assembly to form an immature ______ particle.
Viruses components must be collected at a particular site of the cell and undergo assembly to form an immature ______ particle.
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Most nonenveloped DNA viruses assemble their nucleocapsid in the ______, since that is the site of genome replication.
Most nonenveloped DNA viruses assemble their nucleocapsid in the ______, since that is the site of genome replication.
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Viruses with envelopes derived from the plasma membrane usually assemble at the ______.
Viruses with envelopes derived from the plasma membrane usually assemble at the ______.
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Maturation refers to the final changes within an immature ______.
Maturation refers to the final changes within an immature ______.
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The HA1 portion binds the cell surface ______, the HA2 portion is what fuses the viral envelope to the endosomal membrane to release the virus into the cytoplasm.
The HA1 portion binds the cell surface ______, the HA2 portion is what fuses the viral envelope to the endosomal membrane to release the virus into the cytoplasm.
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Nonenveloped viruses can also exit the cell via ______.
Nonenveloped viruses can also exit the cell via ______.
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Study Notes
Virus Classification and Taxonomy
- The Baltimore classification system categorizes viruses based on the type of nucleic acid genome and replication strategy.
- The system categorizes viruses into seven classes based on their type of genome:
- Class I: Double-stranded DNA (dsDNA) viruses
- Class II: Single-stranded DNA (ssDNA) viruses
- Class III: Double-stranded RNA (dsRNA) viruses
- Class IV: Positive-sense RNA viruses
- Class V: Negative-sense RNA viruses
- Class VI: RNA viruses that reverse transcribe
- Class VII: DNA viruses that reverse transcribe
- Viruses are classified using order, family, genus, and species.
- The classification system uses suffixes to distinguish between different taxonomic levels:
- Order: -virales suffix
- Family: -viridae suffix
- Genus: -virus suffix
- Species: generally the "common name" of the virus
Virus Attachment
- Virus attachment refers to the binding of the virus to the host cell.
- The interaction is specific, with the virus containing a virus attachment protein that adsorbs to a cell surface receptor on the cell.
- Examples of virus attachment include:
- Rhinovirus binding to intercellular adhesion molecule 1 (ICAM-1)
- Influenza A virus binding to sialic acid sugars
- HIV binding to CD4 and coreceptors CCR5 and CXCR4
Virus Replication
- The replication strategy of a virus is dependent on the type of nucleic acid genome it contains.
- Viruses with dsDNA genomes use the enzymes and proteins of the host cell, including DNA polymerases and RNA polymerases.
- RNA genomes do not enter the nucleus and use different replication strategies.
- The replication process involves the synthesis of viral proteins and the replication of the viral genome.
Virus Penetration
- Penetration refers to the crossing of the plasma membrane by the virus, following attachment.
- Enveloped and nonenveloped viruses use different penetration strategies.
- Examples of penetration strategies include:
- Receptor-mediated endocytosis
- Clathrin-mediated endocytosis
- Caveolae-mediated endocytosis
- Bulk-phase endocytosis
Virus Assembly
- Assembly refers to the collection of viral components at a specific site in the cell and the formation of an immature virus particle.
- The assembly site can be in the nucleus, at the plasma membrane, or at intracellular membranes.
- Examples of assembly sites include:
- The nucleus for nonenveloped DNA viruses
- The plasma membrane for enveloped viruses
Virus Maturation
- Maturation refers to the final changes within an immature virion.
- Structural capsid changes are often involved, such as the cleavage of the influenza HA protein into two portions.
Virus Release
- Release refers to the final step in the virus life cycle, where the virus exits the cell.
- Enveloped viruses can bud from the plasma membrane or other membrane systems, undergo exocytosis, and exit the cell.
- Nonenveloped viruses can exit the cell via exocytosis or cause the lysis of the cell.
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Description
This quiz covers the classification and replication of viruses, including the Baltimore classification system and the characteristics of positive-strand RNA.
