Introduction to Microbiology

Study Notes

Microbiology is the scientific study of microorganisms, which are typically less than 1mm in size and require magnification to be viewed clearly.
Microorganisms include bacteria, fungi, protozoa, algae, and viruses, some of which are pathogenic, meaning they can cause disease.
Normal flora refers to non-pathogenic microorganisms that inhabit healthy individuals, commonly found on skin, in respiratory tracts, and intestines.

Historically, living organisms were classified into two kingdoms: Animalia and Plantae.
The complexity of life led to the establishment of a five-kingdom system, which includes Monera, Protista, Fungi, Plantae, and Animalia.
A more recent classification divides life into three major domains: Bacteria (prokaryotes), Archaea (prokaryotes), and Eukaryota (eukaryotes).
Kingdom Monera comprises prokaryotic organisms that lack nuclei, with their cell walls typically composed of peptidoglycan, except for archaebacteria.
Prokaryotes reproduce mainly through binary fission (asexual) or conjugation (sexual).

Taxonomy refers to the classification of organisms and is structured hierarchically from kingdoms down to species.
The five kingdoms are Monera (Prokaryota), Protista, Fungi, Plantae, and Animalia, each divided into phyla, classes, orders, families, genera, and species.
Binomial nomenclature assigns each microorganism a two-part name (genus and species), with the genus capitalized and species in lowercase.

Robert Hooke proposed the Cell Theory in 1665, asserting that all living things are composed of cells.
Francesco Redi conducted experiments disproving spontaneous generation, which suggested life could arise from non-living matter.
Antonie van Leeuwenhoek was the first to observe living microbes using a single-lens microscope magnifying up to 300X.
Louis Pasteur, known as the Father of Modern Microbiology, advanced the understanding of fermentation and disproved spontaneous generation. He developed aseptic techniques and vaccines.
Joseph Lister introduced antiseptic surgery, significantly enhancing surgical practices.

Bacteriology focuses on the study of bacteria.
Mycology deals with the study of fungi.
Virology studies viruses, with Beijerinck discovering the intracellular reproduction of tobacco mosaic virus and coining the term "virus."
Parasitology is the study of protozoa and parasitic worms.

Microbes are organisms not visible to the naked eye and require magnification to observe their unique characteristics.
The Six Kingdoms of Life provide a framework for classifying living organisms: two kingdoms consist of prokaryotes (Monera) and four are eukaryotic (Protista, Fungi, Plantae, Animalia).
Organisms may be unicellular or multicellular, with two kingdoms consisting solely of unicellular organisms.
Different kingdoms exhibit variations in cell wall composition, with some lacking cell walls entirely.