Microorganisms: Viruses, Bacteria, and Fungi

Viruses

• Consist of nucleic acid (DNA or RNA) enclosed in a protein coat
• May have an outer envelope derived from the host cell membrane
• Lack ribosomes, cell walls, and other cellular structures
• Cannot replicate independently, requiring a host cell for reproduction

Bacteria

• Single-celled organisms more complex than viruses
• Diverse shapes: spherical, rod-shaped, filamentous, and comma-shaped
• Possess a cell membrane, but lack a nucleus and mitochondria
• Have a cell wall for protection and shape maintenance
• Utilize oxygen for respiration
• Reproduce asexually, often rapidly
• Some bacteria are pathogenic, causing disease

Fungi

• Diverse group of eukaryotic organisms including yeasts, molds, and mushrooms
• Can be unicellular or multicellular
• Have a defined nucleus and cell walls
• Reproduce sexually or asexually
• Can be parasitic, saprophytic (decomposers), or mutualistic (beneficial relationships)
• Microscopic fungi can cause disease, while macroscopic fungi are often edible

Protozoa

• Diverse group of single-celled eukaryotic organisms
• Lack a cell wall
• Reproduce sexually or asexually
• Have a nucleus, cytoplasm, and various organelles
• Utilize different locomotion mechanisms (e.g., cilia, flagella, pseudopodia)
• Can exist in two forms: trophozoites (active, motile) and cysts (dormant, resistant)
• Some protozoa can be pathogenic, causing disease

Explore the fascinating world of microorganisms through this quiz that covers viruses, bacteria, and fungi. Learn about their structures, reproduction methods, and the roles they play in the ecosystem, including their impact on human health. Test your knowledge and understand the differences between these diverse organisms.