History and Foundations of Microbiology

Flashcards covering the history, major theories, foundational scientists, and classification of microorganisms based on the lecture transcript.

Microbiology

The study of organisms too small to be seen clearly by the naked eye.

Bacteriology

The study of bacteria, which are classified as prokaryotes.

Virology

The study of viruses, which are acellular pathogens.

Mycology

The branch of microbiology that focuses on fungi.

Parasitology

The focus on eukaryotic parasites, including protozoa and helminths.

Immunology

The study of the host response to microbial invaders.

Animalcules

The term used by Antonie van Leeuwenhoek in the 1670s to describe the first observed live microorganisms visualized with a simple microscope.

Miasma Theory

The belief that "bad air" or rotting organic matter was the cause of disease.

Humoral Theory

The theory that disease resulted from an imbalance of four body fluids: blood, phlegm, yellow bile, and black bile.

Germ Theory

The fundamental concept that specific microscopic organisms are the cause of specific infectious diseases.

Pathogen

A microbe capable of causing host tissue damage.

Spontaneous Generation

The theory that life arises from non-life, also referred to as abiogenesis.

Biogenesis

The principle that life arises only from pre-existing life, often stated as "Omne vivum ex vivo".

Endospores

Extremely heat-resistant microbial structures discovered by John Tyndall.

Tyndallization

A process of repeated boiling and cooling used to kill germinating spores.

Pasteurization

A method developed by Louis Pasteur involving brief exposure to heat below boiling to kill pathogenic microbes while preserving product quality.

Koch’s Postulates

A rigorous 4-step framework used to prove that a specific microbe is the cause of a specific disease.

Antisepsis

The clinical practice of using chemical agents, such as carbolic acid (phenol), to clean wounds and surgical instruments.

Fermentation

The chemical breakdown of substances like glucose into ethanol or lactic acid by microorganisms in the absence of oxygen.

HTST (High-Temperature Short-Time)

A common pasteurization method for milk involving heating to $72 ext{°C}$ for $15$ seconds.

UHT (Ultra-High Temperature)

A pasteurization method involving heating to $138 ext{°C}$ for $2$ seconds to create shelf-stable products.

Taxonomy

The science of naming and classifying organisms based on shared characteristics.

Binomial Nomenclature

The system of naming organisms using two parts: the Genus (capitalized) and the species (lowercase), both of which are italicized.

Gram Stain

A diagnostic tool that differentiates bacteria into two categories based on cell wall composition.

Gram-Positive

Bacteria that stain purple due to a thick peptidoglycan layer in their cell walls.

Gram-Negative

Bacteria that stain pink or red, possessing a thin peptidoglycan layer and an outer lipopolysaccharide (LPS) membrane.

Acellular

A characteristic of viruses indicating they are not composed of cells, but rather genetic material (DNA or RNA) in a protein coat.

Obligate Intracellular Parasites

Organisms that cannot reproduce outside of a living host cell, such as viruses.

Helminths

Multicellular parasitic worms, such as tapeworms and flukes, classified as microbes because their eggs or larvae are microscopic.