MCQs

Plant viruses often enter through injuries and are spread by insect vectors.

Capsomeres are repeating protein units that assemble into the viral capsid.

Hepatitis B virus is a DNA virus and an important human pathogen.

Tail fibers recognize and bind specific bacterial receptors.

Influenza virus contains a segmented RNA genome.

TMV exhibits a rigid rod-shaped helical symmetry.

Viruses depend entirely on host cellular machinery for replication.

Poliovirus belongs to the RNA viruses and contains positive-sense single-stranded RNA.

Viral envelopes are obtained from host cell membranes during viral budding.

Viruses infect cells possessing specific receptors complementary to viral attachment proteins.

Rabies virus affects the nervous system and commonly causes hydrophobia in infected individuals.

HIV attacks helper T lymphocytes and causes Acquired Immunodeficiency Syndrome (AIDS).

TMV is a classic plant virus containing single-stranded RNA enclosed in a helical capsid.

Bacteriophages are viruses specialized to infect bacterial cells.

Capsid protects the viral genome and helps in host recognition. Envelope is an additional structure found only in some viruses.

A virus contains either DNA or RNA as genetic material but never both simultaneously.

Viruses can reproduce only inside living host cells because they lack independent metabolic machinery.

Viruses lack cellular organization and consist mainly of nucleic acid enclosed by a protein coat, making them acellular infectious particles.

Capsid is the protein coat that surrounds viral nucleic acid and is present in all viruses. Ribosomes, cytoplasm, and true cellular membranes are absent in all viruses.