What are the three bases for classifying viruses?
Morphology, genome, and host
What are the five morphological types of viruses?
Tadpole-like, polyhedral capsid, helical capsid, complex enveloped capsid, and bullet-shaped
Which virus has a tadpole-like morphology?
Bacteriophage
Which virus has a polyhedral capsid?
Adenovirus
What is the shape of the Tobacco Mosaic Virus (TMV) capsid?
Helical (rod-shaped)
Which viruses have complex enveloped capsids with spikes?
Influenza virus and HIV
What type of capsid does a bullet-shaped virus have?
V-shaped capsid
What is the morphology of bacteriophages?
Complex morphology
What features are present at each vertex of some polyhedral viruses?
Spikes
Which virus is described as having a rod-shaped helical capsid?
Tobacco Mosaic Virus (TMV)
What surrounds the capsid of complex enveloped viruses?
Spikes
Does the viral envelope make a virus more tolerant to antibodies?
No (because loss of the envelope removes spikes, so the virus can no longer infect).
Footnote: The viral envelope is a lipid bilayer that contains glycoprotein spikes, which are essential for host cell recognition and entry. If the envelope is destroyed (by heat, drying, detergents, disinfectants, or antibodies), the spikes are lost. Without these spikes, the virus cannot infect, even though the capsid remains. This makes enveloped viruses more vulnerable and less resistant. By contrast, non-enveloped viruses use their tough protein capsid for attachment, which allows them to resist harsh conditions such as acid, bile salts, and alcohol.
What molecule do animal cells use to control viruses during infection?
Interferon (interferes with viral replication)
The genetic code of which virus is bound by a lipid membrane?
Flu virus / influenza virus
Which molecule controls viruses during infection of animal cells?
Interferon [Footnote: Interferons are proteins released by infected animal cells that interfere with viral replication and protect neighboring cells.]
What is the role of an antigen?
Antigen triggers an immune response but does not directly stop viruses. [Footnote: Antigens are viral or foreign molecules recognized by the immune system.]
What is the role of histones?
Histones package DNA in eukaryotic cells, not involved in viral control. [Footnote: Their function is structural, not antiviral.]
What is serum and its role in immunity?
Serum is the fluid part of blood after clotting, containing antibodies and proteins that help fight infection. [Footnote: Useful for immunity, but not the direct molecule animal cells use against viruses.]
How to quickly remember which molecule fights viruses in animal cells?
Interferon “interferes” with viruses. [Footnote: Think of interferon as a natural antiviral protein.]
Which virus kills cancer cells and aids immunity
Oncolytic
What are three true characteristics of enveloped viruses?
They survive for a short time outside a host; their envelope is sensitive to sunlight; and the envelope is derived from the host cell.
