Which term refers to a microorganism that lacks cellular structure and is smaller than bacteria?

Which term refers to a microorganism that lacks cellular structure and is smaller than bacteria?

• A. Virus
• B. Protozoa
• C. Fungus
• D. Bacteria

Answer: (A)

Viruses are acellular particles that lack cellular structure and are smaller than bacteria. They’re made of genetic material (DNA or RNA) enclosed in a protein coat, and sometimes a lipid envelope. Because they don’t have a cell membrane, cytoplasm, or organelles, viruses can’t carry out metabolism or replicate on their own; they must hijack a host cell’s machinery to reproduce. That’s what sets them apart from other microorganisms like protozoa and fungi, which are cellular eukaryotes, and bacteria, which are cellular prokaryotes.

Viruses are acellular particles that lack cellular structure and are smaller than bacteria. They’re made of genetic material (DNA or RNA) enclosed in a protein coat, and sometimes a lipid envelope. Because they don’t have a cell membrane, cytoplasm, or organelles, viruses can’t carry out metabolism or replicate on their own; they must hijack a host cell’s machinery to reproduce. That’s what sets them apart from other microorganisms like protozoa and fungi, which are cellular eukaryotes, and bacteria, which are cellular prokaryotes.