Biological Classification and Microbiology

Kingdom Protista

• Most diverse kingdom; organisms can be animal-like, plant-like, or fungus-like.
• Protists are eukaryotes not classified as animals, plants, or fungi.

Animal-like Protists (Protozoa)

• Move in various ways:
  • Amoebas: Use pseudopods.
  • Paramecium: Use cilia.
  • Euglena: Use flagella.
• Diseases caused by protozoa:
  • Malaria: Caused by Plasmodium, spread by mosquitoes.
  • Sleeping Sickness: Caused by Trypanosoma, spread by flies.

Kingdom Fungi

• Multicellular organisms (except yeasts), with cell walls made of chitin.
• Reproduce asexually through budding or spores.
• Role in ecosystems as decomposers.
• Examples of fungi-related diseases: Athlete's foot.
• Lichens: Symbiotic relationship between fungi and algae.
• Mycorrhizae: Symbiosis between fungi and plant roots.

Kingdom Eubacteria

• Includes true bacteria and cyanobacteria (photosynthetic).
• Main reproduction method: Asexual by binary fission and conjugation (simple sexual reproduction).
• Essential roles: live in animals' digestive systems, produce food (yogurt, cheese), and fix nitrogen.
• Some bacteria can cause diseases (food poisoning, tetanus, sore throat).
• Antibiotics used against bacteria; ineffective against viruses.

Genetic Recombination in Bacteria

• Methods include:
  • Transformation: Uptake of foreign DNA.
  • Conjugation: Exchange of DNA through a bridge.
  • Transduction: DNA transfer via bacteriophage.

Taxonomy

• KPCOFGS: Kingdom, Phylum, Class, Order, Family, Genus, Species.
• Binomial Nomenclature: Two-part naming system (Genus species).
• Example: Panthera tigris (Tiger).

Classification Systems

• Old 5 Kingdom system: Monera, Protists, Plants, Fungi, Animals.
• New 3 Domain system: Archaebacteria, Eubacteria, Eukarya.

Viruses and Pathogens

• Pathogen: Disease-causing agent (viruses, bacteria, viroids, prions).
• Viruses: Non-living, must have a host to replicate; can cause two types of infections: lytic (cell lyses) and lysogenic (integrates into host DNA).
• Common diseases caused by viruses: Common cold, flu, mumps.

Archaebacteria

• Found in extreme environments: volcanic vents, acidic springs.
• Types:
  • Methanogens: Live without oxygen.
  • Extreme Halophiles: Live in salty environments.
  • Thermophiles: Live in hot environments.