Microbiology: Specialized area of biology focusing on organisms too small to be seen without magnification.
Microorganisms (Microbes): Include bacteria, archaea, protozoans, fungi, helminths, viruses, algae.
Types of Microorganisms
Bacteria: Prokaryotic, unicellular, often have peptidoglycan cell walls, reproduce by binary fission, can be autotrophic or heterotrophic.
Archaea: Prokaryotic, similar to bacteria but lack peptidoglycan in cell walls, often extremophiles, also reproduce by binary fission.
Fungi: Eukaryotic, can be unicellular (yeasts) or multicellular (molds and mushrooms), have chitin cell walls, heterotrophic.
Protozoans: Eukaryotic, usually lack cell walls, heterotrophic, motile by pseudopods, flagella, or cilia.
Algae: Eukaryotic, photosynthetic, can be unicellular or multicellular, have cellulose cell walls.
Viruses: Acellular, non-living, require host cells to reproduce, can have DNA or RNA, have a protein coat or capsid.
Helminths: Multicellular animal parasites like worms, heterotrophic, reproduce sexually or asexually.
Microbes in Ecosystems
Essential to earth's habitat for billions of years.
Photosynthesis: Microbes contribute significantly to Earth's oxygen through photosynthesis.
Influence soil, water, and atmospheric conditions.
Human Uses of Microbes
Production of food (bread, alcohol, cheese).
Antibiotics and treatments for diseases.
Biotechnology applications, including genetic engineering and bioremediation.
Historical Context
Spontaneous Generation vs. Biogenesis: Debate over the origin of life, with experiments by Francesco Redi, Louis Pasteur supporting biogenesis (life from life).
Notable Figures:
Anton van Leeuwenhoek: First to observe living microorganisms.
Robert Hooke: Described cells.
Louis Pasteur: Disproved spontaneous generation, developed pasteurization.
Ignace Semmelweis: Advocated hand washing.
Joseph Lister: Introduced antiseptic techniques in surgery.
Robert Koch: Developed Koch's postulates, linking specific microbes to specific diseases.
Edward Jenner: Developed first vaccine (smallpox).
Alexander Fleming: Discovered penicillin.
Modern Advances
PCR (Polymerase Chain Reaction): Amplifies DNA, crucial for forensic science and diagnostics.
Human Microbiome Project: Studies the role of human-associated microbes in health and disease.
Classification and Nomenclature
Taxonomy: Science of classification with hierarchical categories: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
Binomial Nomenclature: Genus and species names are used (e.g., Homo sapiens), important for scientific communication.
Domains: Three-domain system includes Bacteria, Archaea, and Eukarya.