MCQs

Baltimore Group III viruses contain double-stranded RNA genomes and require viral RNA-dependent RNA polymerase for replication.

Poliovirus infects motor neurons and may cause poliomyelitis, leading to paralysis in severe cases.

Naked viruses lack a lipid envelope, making them more resistant to drying, acids, and detergents than enveloped viruses.

Viral glycoproteins embedded in the envelope recognize host receptors and facilitate membrane fusion during infection.

Bacteriophages are highly specific viruses that infect bacteria and cannot infect plant or animal cells.

DNA viruses contain DNA as their genetic material, whereas RNA viruses contain RNA. A virus never contains both DNA and RNA simultaneously.

Tobacco Mosaic Virus causes mosaic-like discoloration on tobacco and several other plant leaves, reducing crop yield.

Bacteriophages specifically infect bacterial cells by attaching to receptors on the bacterial cell wall.

Rabies virus has a bullet-shaped appearance but internally possesses a helical nucleocapsid.

Adenovirus is a classic example of a naked virus with an icosahedral capsid, making it highly resistant to environmental conditions.

Adenoviruses possess a linear double-stranded DNA genome enclosed in an icosahedral capsid.

Influenza virus infects humans, birds, and several mammals, therefore it belongs to the animal viruses.

Lipid envelopes are easily disrupted by heat, drying, soaps, and detergents, making enveloped viruses less stable outside the host.

Human Immunodeficiency Virus (HIV) is a retrovirus containing single-stranded RNA and the enzyme reverse transcriptase.

Positive-sense ssRNA viruses can be translated immediately by host ribosomes upon entering the host cell.

Hepatitis B virus is a partially double-stranded DNA virus belonging to the Hepadnaviridae family. It replicates through reverse transcription but is classified as a DNA virus.

T4 bacteriophage possesses an icosahedral head, helical tail, and tail fibers, making it the classic example of a complex virus.

TMV infects tobacco and many related plants but cannot infect animal cells because of host specificity.

Naked viruses possess only a nucleic acid core surrounded by a protein capsid and are generally more resistant to environmental conditions.