Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

What is a bacteriophage?

1. A virus that attacks bacterial cells

2. A type of bacterial infection

3. A bacterium that helps in digestion

4. A human disease caused by a virus

The correct answer is: A virus that attacks bacterial cells

A bacteriophage is indeed a virus that specifically targets and attacks bacterial cells. These viruses infect bacteria by attaching to the bacterial surface and injecting their genetic material into the bacterial cell. Once inside, the bacteriophage takes over the bacterial machinery to replicate itself, ultimately leading to the destruction of the bacterial cell when new virions are released. This process is significant in various fields, including medicine and biotechnology, as bacteriophages can be used as tools for phage therapy to combat antibiotic-resistant bacterial infections. Unlike other types of viruses that infect human or plant cells, bacteriophages are highly specific to their bacterial hosts, making them an interesting subject of study in virology and microbiology. The other options describe different biological entities or processes that do not accurately capture the definition of a bacteriophage. A bacterial infection involves the growth of bacteria in a host organism, while bacteria that aid in digestion are part of the microbiome, and human diseases caused by viruses typically refer to infections in human cells, not bacteria.