History of Microbiology and Microscopy - Flashcards

A set of practice flashcards covering the key concepts and facts from the lecture notes on the history of microbiology, germ theory, key scientists, microscopy, staining, and bacterial morphology.

What is microbiology?

The study of living things too small to be seen without magnification.

Name the major groups of organisms studied in microbiology.

Bacteria and Archaea; Fungi; Protozoa (Protists); Helminths; and Acellular agents (Viruses and Prions).

What are the defining features of Bacteria and Archaea?

Unicellular, lack nuclei (prokaryotic), much smaller than eukaryotes, found wherever moisture is present; some live in extreme environments.

What characterizes Fungi?

Eukaryotic; obtain food from other organisms; have cell walls; molds (hyphae and spores) and yeasts (unicellular, reproduce asexually).

What are Protozoa (Protists) like?

Single-celled eukaryotes; similar to animals in nutrient needs and cellular structure; live freely in water or in animal hosts; mostly asexual and sexual reproduction; capable of locomotion.

What are Helminths?

Parasitic worms; eukaryotic; multicellular; adult stages macroscopic; many life stages microscopic.

What are acellular agents?

Viruses are acellular, obligate intracellular parasites and very small; Prions are proteins with no genetic material and can cause disease.

Define abiogenesis and biogenesis.

Abiogenesis is spontaneous generation (life arising from nonliving matter); biogenesis is life arising from preexisting life.

What was Aristotle’s view on the origin of life?

Ancient belief that living things arise from vital forces; spontaneous generation was later disputed by biogenesis.

What did Redi’s experiments demonstrate?

Decaying meat isolated from flies did not develop maggots, challenging spontaneous generation.

Who is considered the father of microbiology and protozoology?

Antonie van Leeuwenhoek; built powerful microscopes and observed protozoa (‘animalcules’) and bacteria.

What did Robert Hooke contribute to cell theory?

Described cellulae (cells) in cork; contributed to the cell theory that cells are the basic units of life; first to publish a microorganism description (fungus).

What were Pasteur’s key contributions?

Disproved abiogenesis; showed microbes come from air and cause decay; developed pasteurization; germ theory of disease; vaccines.

What is pasteurization?

Heating liquids to kill microbes to prevent spoilage and extend shelf life.

Explain Koch’s postulates.

1) The causative agent must be present in every diseased individual; 2) It must be isolated and grown in pure culture; 3) The pure culture must cause disease when inoculated into an experimental animal; 4) The agent must be re-isolated from the experimental animal in pure culture.

What techniques and tools are associated with Koch’s experiments?

Simple staining; first photomicrograph of bacteria; estimating CFU/ml; steam sterilization; Petri dishes; aseptic techniques.

Who introduced aseptic technique in surgery?

Joseph Lister; advocated handwashing, sterilization, and clean clothing to prevent infection.

What is Ignaz Semmelweis known for?

Handwashing to prevent puerperal fever in obstetric patients.

What is the purpose of microscopy and staining in microbiology?

To study bacteria by increasing contrast and revealing cellular features for identification and characterization.

Describe the basic parts of a light microscope.

Ocular lens, objective lenses, stage, condenser, diaphragm, illuminator, coarse and fine focusing knobs, arm, base.

What is immersion oil used for in microscopy?

Reduces refraction losses between slide and objective lens, increasing resolution and brightness.

What are the main types of microscopes?

Light microscopy (bright-field, simple and compound); Electron microscopy (TEM and SEM); other advanced types like STM and AFM.

What sizes and capabilities are associated with TEM, SEM, and LM?

TEM ~0.078 nm to 100 μm; SEM ~0.4 nm to 1 mm; LM ~200 nm to 10 mm (with immersion oil, etc.).

What is Gram staining used for?

Differentiates Gram-positive (purple) and Gram-negative (pink) bacteria; a first step in identification; helps distinguish genera like Mycobacterium and Nocardia.

What does Ziehl-Neelsen staining detect?

Acid-fast bacteria, such as Mycobacterium species.

What does the endospore stain reveal?

Green endospores and pink/red vegetative cells.

What is the purpose of negative staining?

Background is stained while cells remain unstained to reveal capsules.

List common bacterial shapes and arrangements.

Shapes: cocci (spherical), bacilli (rods), coccobacilli, vibrio (curved), spirillum (spiral), spirochetes (corkscrew); Arrangements: singles, diplococci/diplobacilli, tetrads, irregular clusters (staphylococci, micrococci), palisades.

What are the take-home points about microbiology history?

Understand germ theory, Koch’s postulates, antiseptic technique, and fermentation; know microscope types and limits; know bacterial morphology.