A virus that is specific for a bacterial host is called a __________ .
a. Phage
b. Prion
c. Virion
d. Viroid

Verified step by step guidance

1. Understand the question: It asks for the name of a virus that specifically infects bacterial hosts.
2. Recall definitions of each option: (a) Phage refers to bacteriophages, viruses that infect bacteria; (b) Prions are infectious proteins, not viruses; (c) Virion is the complete virus particle, not specific to bacteria; (d) Viroids are infectious RNA molecules that affect plants, not bacteria.
3. Identify the correct term based on the definitions: The virus specific to bacteria is called a bacteriophage, commonly shortened to phage.
4. Confirm that 'phage' is the term used in microbiology to describe viruses that infect bacterial cells.
5. Conclude that the correct answer is option (a) phage.

Key Concepts

Bacteriophage (Phage)

A bacteriophage, or phage, is a virus that specifically infects bacteria. It attaches to the bacterial cell, injects its genetic material, and uses the host's machinery to replicate. Phages are important in molecular biology and bacterial genetics.

Prion

Prions are infectious proteins that cause neurodegenerative diseases by inducing abnormal folding of normal proteins in the brain. Unlike viruses, prions lack nucleic acids and do not infect bacteria, making them distinct from bacteriophages.

Virion and Viroid

A virion is the complete, infectious form of a virus outside a host cell, while a viroid is a small, circular RNA molecule that infects plants but lacks a protein coat. Neither term specifically refers to viruses that infect bacteria.