RNA viruses may be positive-sense, negative-sense, or double-stranded: True/false

• Prokaryotes: cells contain 70S ribosomes
• Virus: DNA or RNA subtypes
• Flagella: long, helical protein structures
• Cilia: tiny hairlike appendages

• Prokaryotes: cells contain 70S ribosomes: Prokaryotic cells lack membrane-bound organelles and have 70S ribosomes, which are smaller than the 80S ribosomes found in eukaryotes. These ribosomes are essential for protein synthesis and are a distinguishing feature of prokaryotic cells, helping differentiate them from eukaryotic cells in microbiology.

• Virus: DNA or RNA subtypes: Viruses are acellular organisms that contain either DNA or RNA as their genetic material, never both. The type of nucleic acid determines their classification, replication strategy, and pathogenic mechanisms. Viruses rely on host cells for reproduction, as they lack the machinery for independent protein synthesis.

• Flagella: long, helical protein structures: Bacterial flagella are long, helical filaments made of the protein flagellin. They function in motility, allowing bacteria to move toward favorable environments or away from harmful conditions. Flagella are structurally distinct from cilia, which are shorter and more numerous.

• Cilia: tiny hairlike appendages: Cilia are short, hairlike structures on the surface of some eukaryotic cells that beat rhythmically to move fluids, mucus, or cells. They are primarily involved in movement and environmental sensing, and are much shorter and more numerous than flagella, making them easily distinguishable.

Pili, also called sex pili, are hair-like appendages on the surface of many bacteria that are longer than fimbriae and play a key role in bacterial conjugation. During conjugation, a donor bacterium uses a pilus to attach to a recipient cell and transfer genetic material, typically plasmids, which can carry genes for antibiotic resistance or other traits. Fimbriae, in contrast, are shorter and primarily function in adhesion to surfaces or host tissues, not in genetic exchange. The structural and functional distinction between pili and fimbriae allows bacteria to both attach to environments and share genetic information for survival and adaptation.