Bacterial Classification and Motility Quiz

Bacteria

• Unicellular, prokaryotic microorganisms with no true nucleus or membrane-bound organelles.
• Found in diverse environments, including extreme conditions like hot springs and deep-sea vents.

Motility

• Some bacteria, like Salmonella, are motile and possess flagella; others are non-motile.

Classification

• Domain: Bacteria
• Kingdom: Monera (or Bacteria)

Examples

• Escherichia coli (E. coli) – Gram-negative rod.
• Staphylococcus aureus – Gram-positive cocci.
• Mycobacterium tuberculosis – Acid-fast bacterium causing tuberculosis.

Reproduction

• Asexual:
  • Binary Fission: Primary reproduction method, where one cell divides into two identical cells.
  • Horizontal Gene Transfer:
    • Conjugation: Genetic material transfer through direct contact.
    • Transformation: Uptake of free DNA from the environment.
    • Transduction: DNA transfer between bacteria via bacteriophages.

Viruses

• Non-cellular, obligate intracellular parasites made of genetic material (DNA or RNA) enclosed in a protein coat (capsid).
• Can only replicate within a host cell.

Morphological Characteristics

• Size: Typically 20 to 300 nanometers, smaller than bacteria.
• Shape:
  • Icosahedral: Symmetrical, spherical (e.g., Adenovirus).
  • Helical: Rod-like (e.g., Tobacco mosaic virus).
  • Complex: Combination of shapes (e.g., Bacteriophage).

Components

• Capsid: Protein coat composed of capsomeres.
• Envelope: Some have an outer lipid membrane (e.g., Influenza virus).
• Genetic Material: DNA or RNA, can be single-stranded or double-stranded, linear or circular.

Classification

• By Genetic Material:
  • DNA Viruses: e.g., Adenovirus.
  • RNA Viruses: e.g., Influenza virus, HIV.
• By Host Range:
  • Bacteriophages: Infect bacteria (e.g., T4 bacteriophage).
  • Animal Viruses: Infect animal cells (e.g., Rabies virus).
  • Plant Viruses: Infect plant cells (e.g., Tobacco mosaic virus).

Reproduction

• Lytic Cycle:

  • Attachment: Virus binds to host cell.
  • Penetration: Viral genetic material enters host cell.
  • Biosynthesis: Host cell synthesizes viral components.
  • Assembly: Formation of new viral particles.
  • Release: Host cell bursts, releasing new viruses.

• Lysogenic Cycle: Viral DNA integrates into host genome, replicates without harming the host.

Fungi

• Eukaryotic organisms that can be unicellular (yeasts) or multicellular (molds, mushrooms).
• Non-photosynthetic; obtain nutrients through absorption.

Morphological Characteristics

• Structure:
  • Yeasts: Unicellular, often oval or spherical (e.g., Saccharomyces cerevisiae).
  • Molds: Multicellular with filamentous hyphae forming mycelium (e.g., Aspergillus).
  • Mushrooms: Fruiting bodies with a cap and stalk (e.g., Agaricus).
• Cell Wall: Composed of chitin and glucans.
• Spores: Reproductive units, can be asexual or sexual.
• Dimorphism: Some fungi switch forms based on environmental conditions (e.g., Histoplasma capsulatum).

Classification

• Kingdom: Fungi
• Phyla:
  • Ascomycota: Sac fungi (e.g., Penicillium).
  • Basidiomycota: Club fungi (e.g., Agaricus).
  • Zygomycota: Conjugation fungi (e.g., Rhizopus).
  • Chytridiomycota: Aquatic fungi (e.g., Batrachochytrium).

Reproduction

• Asexual:
  • Budding: Seen in yeasts (e.g., Saccharomyces cerevisiae).
  • Fragmentation: Hyphae break into pieces, each capable of forming a new fungus.
  • Spore Formation: Conidia or sporangiospores formed via mitosis.
• Sexual:
  • Plasmogamy: Fusion of two hyphae.
  • Karyogamy: Fusion of nuclei.
  • Meiosis: Produces sexual spores (e.g., ascospores, basidiospores).

Protozoans

• Unicellular, eukaryotic microorganisms that can be free-living or parasitic.
• Heterotrophic with diverse morphologies.

Morphological Characteristics

• Shapes include:
  • Amoeboid: Irregular shape using pseudopodia (e.g., Amoeba).
  • Ciliated: Covered with cilia for movement (e.g., Paramecium).

Historical Milestones in Immunology

• 1798: Edward Jenner published findings on vaccination, promoting smallpox vaccine use globally.
• 1928: Alexander Fleming discovered penicillin, the first true antibiotic from Penicillium notatum.
• 1940s: Mass production of penicillin began, revolutionizing bacterial infection treatments.

Test your knowledge on the classification, motility, and reproduction of bacteria. This quiz covers important examples such as E. coli and Staphylococcus aureus, along with their characteristics and modes of reproduction. Dive into the fascinating world of microbiology and see how much you know!