Which type of acellular infectious agent depends on living host cells to reproduce?

• A. Viroid
• B. Prion
• C. Bacterium
• D. Virus

Answer: (D)

Verified step by step guidance

1. Understand the definition of an acellular infectious agent: these agents lack cellular structure and cannot carry out metabolic processes independently.
2. Review the options given: Viroid, Prion, Bacterium, and Virus, and identify which are acellular and which are cellular.
3. Recall that bacteria are cellular organisms capable of independent reproduction, so they are not acellular infectious agents.
4. Recognize that prions are infectious proteins that do not contain nucleic acids and do not reproduce by themselves, but rather induce misfolding of normal proteins.
5. Identify that viruses are acellular infectious agents composed of nucleic acid and protein that require living host cells to reproduce, as they lack the machinery for independent replication.