DNT 509 Oral Biology Lec1

Microbiology Overview

  • Definition: Study of microorganisms (bacteria, viruses, fungi, protozoa) not visible to the naked eye.

  • Importance: Vital to Earth processes, affecting all life aspects.

Microflora

  • Community of bacteria in/on the body with ecological relationships with the host.

Microbiology Disciplines

  • Branches: Bacteriology, Mycology, Parasitology, Virology, Phycology, Protozoology.

History of Microbiology

  • Key Figures:

    • Robert Hooke: Early observations using microscopes.

    • Anton van Leeuwenhoek: First described microorganisms in 1675.

    • Louis Pasteur: Founded microbiology, germ theory, vaccinations, and pasteurization.

    • Robert Koch: Identified bacteria as disease agents, developed Koch's postulates.

Germ Theory

  • Suggests microorganisms cause infectious diseases.

  • Pasteur's experiments supported this theory against miasma theory.

Key Concepts of Bacteriology

  • Bacterial Features:

    • Unicellular, prokaryotic lacks nucleus, classified into domains (Archaea, Bacteria, Eukarya).

    • Structure: Cell wall (peptidoglycan), plasma membrane, ribosomes (70S).

    • Growth and Reproduction: Binary fission, genetic adaptation through plasmids.

Bacterial Cell Structure

  • Components:

    • Cell wall, plasma membrane, nucleoid (genetic material) without a nuclear membrane.

    • Ribosomes, flagella (motility), pili (attachment), and capsules/slime layers (protection).

Viruses

  • Definition: Obligate intracellular parasites made of RNA/DNA and a protein coat (capsid).

  • Classification: Based on nucleic acid and structure (enveloped/naked).

  • Discovery: First recognized in late 19th century, significant advances in the 20th century with technology like electron microscopy.

Fungi

  • Eukaryotic organisms with chitin cell walls.

  • Classified into four divisions based on sexual reproduction mechanisms (Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota).

Protozoa

  • Unicellular, diverse eukaryotes, classified by movement (Rhizopoda, Ciliates, Flagellates, Sporozoans).

Helminths

  • Large, multicellular organisms, can be free-l