Viruses Flashcards
What is a Virus?
An infectious agent consisting of genetic material (DNA or RNA) inside a protein coat.
What is a Capsid?
A protein shell that encloses the viral genome.
What is an Envelope?
Modified piece of the host of the host cell membrane.
What is a Naked Virus?
A virus consisting only of a nucleocapsid without an envelope.
What are Spikes?
Glycoproteins on a virus surface that help it attach to host cells.
What is a Virion?
A fully formed virus capable of infecting a host cell.
What is a Helical Capsid?
Capsid with a spiral structure surrounding the viral genome.
What is an Icosahedral Capsid?
Capsid with a 3D, 20-sided shape with evenly spaced corners.
What is a Complex Capsid?
A virus structure that does not fit helical or icosahedral shapes.
What is Positive Sense RNA?
Single-stranded RNA ready for immediate translation.
What is Negative Sense RNA?
RNA that must be converted into a readable form before translation.
What are Polymerases?
Enzymes that synthesize DNA and RNA in viral replication.
What is Reverse Transcriptase?
Enzyme that synthesizes DNA from an RNA template (e.g., HIV).
What is the General Virus Life Cycle?
Includes adsorption, penetration, uncoating, synthesis, assembly, and release.
What is Specific Attachment?
Virus enters a host cell via endocytosis.
What is Irreversible Attachment?
Viral membrane fuses with the host membrane to release nucleic acid.
What are Cytopathic Effects?
Virus-induced cellular damage altering the cell’s shape or function.
What is an Inclusion Body?
Compact mass of virus or damaged organelles inside a host cell.
What are Syncytia?
Fusion of multiple host cells into one large multinucleated cell.
What is a Provirus?
Viral DNA that is incorporated into the host genome.
What is a Chronic Latent State?
A virus that remains dormant and reactivates periodically.
What is an Oncogenic Virus?
Virus that can cause cancer by altering host cell growth regulation.
What is Transformation?
Process where viral genes induce uncontrolled cell growth, increasing cancer risk.
What is the Lytic Cycle?
Virus replication that results in host cell destruction.
What is the Lysogenic Cycle?
Viral DNA integrates into the host genome, remaining dormant before activation.
What is a Temperate Phage?
A bacteriophage that can enter either the lytic or lysogenic cycle.
What is Induction?
The process by which a prophage exits dormancy and enters the lytic cycle.
What is Lysogenic Conversion?
Bacteria gain new traits due to viral DNA integration.
What is In Vivo Cultivation?
Growing viruses in living organisms like animals or embryonic tissues.
What is In Vitro Cultivation?
Growing viruses in cell or tissue cultures.
What are Plaques?
Visible areas of cell destruction in tissue culture due to viral infection.
What are Spongiform Encephalopathies?
Diseases caused by prions, leading to brain degeneration.
What are Prions?
Infectious misfolded proteins that cause neurodegenerative diseases.
What is Creutzfeldt-Jakob Disease (CJD)?
A prion disease that affects the central nervous system, leading to degeneration and death.
What is a Satellite Virus?
A virus that requires another virus for replication.
What are Viroids?
Naked RNA strands that infect plants, lacking a capsid or envelope.
What is Interferon?
A protein made in humans that helps prevent viral infections.
What is a virus?
A virus is a microscopic infectious agent that replicates only inside the living cells of an organism.
True or False: Viruses are considered living organisms.
False
Fill in the blank: Viruses consist of genetic material surrounded by a _______.
capsid
What are the two main types of viral genetic material?
DNA and RNA
Multiple Choice: What is the primary function of a virus’s capsid?
To protect the viral genetic material
What is the process by which a virus infects a host cell?
Viral entry
True or False: All viruses can be cultured in a laboratory.
False
Fill in the blank: A virus that infects bacteria is called a _______.
bacteriophage
What is the term for the complete virus particle?
Virion
Multiple Choice: Which of the following is NOT a method of viral transmission?
Photosynthesis
What is the difference between lytic and lysogenic cycles?
Lytic cycle results in the destruction of the host cell, while lysogenic cycle integrates viral DNA into the host genome.
True or False: Viruses can be treated with antibiotics.
False
Fill in the blank: The study of viruses is known as _______.
virology
What is a viral envelope?
A lipid membrane that surrounds some viruses, derived from the host cell.
Multiple Choice: Which of the following diseases is caused by a virus?
Influenza
What is a vaccine’s role in viral infections?
To stimulate the immune system to recognize and fight off the virus.
True or False: All viruses are harmful to humans.
False
Fill in the blank: The __________ is the host organism that a virus infects.
host
What is the term for a virus that causes cancer?
Oncovirus
Multiple Choice: Which virus is responsible for the common cold?
Rhinovirus
What is the significance of viral mutations?
They can lead to new strains that may evade the immune system or change transmissibility.
True or False: Viruses can reproduce on their own.
False
Fill in the blank: Antiviral drugs are used to treat _______ infections.
viral
What is the role of reverse transcriptase in retroviruses?
To convert viral RNA into DNA.
Multiple Choice: Which of the following is a characteristic of viruses?
They require a host cell to replicate.
What is the term for the immune response triggered by a viral infection?
Adaptive immunity
True or False: All viruses have an outer lipid envelope.
False
