Main Themes of Microbiology – BIOL 107

Vocabulary cards covering core terms, scientists, cell types, measurement units, and historical concepts from the lecture notes.

Microbiology

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

Microbe (Microorganism)

Any microscopic organism; dominant form of life on Earth in numbers, biomass, and impact.

Prokaryotic Cell

Small cell type lacking a nucleus and membrane-bound organelles; DNA is a single circular strand.

Eukaryotic Cell

Larger cell type with DNA in chromosomes, a nucleus, and membrane-bound organelles.

Bacteria

Unicellular, prokaryotic microorganisms such as Escherichia coli.

Archaea

Prokaryotic microbes distinct from bacteria; often thrive in extreme environments.

Fungi

Eukaryotic microbes that may be unicellular (yeasts) or multicellular (molds, mushrooms).

Protozoa

Broad group of unicellular, eukaryotic microbes; classification considered outdated by some.

Virus

Acellular infectious agent composed of nucleic acid and a protein coat; replicates only inside host cells.

Capsid

Protein coat surrounding viral nucleic acid.

Nucleocapsid

The combined viral capsid and enclosed nucleic acid.

Viral Envelope

Lipid membrane surrounding some viruses, derived from host cell membranes.

Biofilm

Community of microbes that adhere to each other and surfaces, embedded in a self-produced matrix.

Colony

Visible mass of microbial cells originating from one parent cell, grown on solid media.

Metric System

Decimal-based system of measurement used to size microbes (meters, centimeters, millimeters, etc.).

Micrometer (µm)

One-millionth of a meter (10⁻⁶ m); common unit for bacterial size.

Nanometer (nm)

One-billionth of a meter (10⁻⁹ m); common unit for viruses and molecular structures.

Dimensional Analysis

Method of converting between units using conversion factors.

Conversion Factor

Ratio expressing equivalence between two units (e.g., 1 cm = 10 mm).

Scientific Notation

Compact way to express very large or small numbers as a coefficient times 10 raised to a power.

Light Microscope

Instrument that uses visible light to magnify objects roughly 1 mm to 1 µm in size.

Electron Microscope

Microscope that uses electron beams to view objects smaller than 1 µm, including viruses and DNA.

Limit of Naked Eye

Approximately 1 millimeter; smallest size humans can generally see without magnification.

Robert Hooke

Scientist who first observed microbes (not bacteria) and coined the term “cell” (1665).

Anton van Leeuwenhoek

First microbiologist; observed and described bacteria with single-lens microscopes (~300–500×).

Abiogenesis (Spontaneous Generation)

Disproven belief that living organisms arise from non-living matter.

Biogenesis

Concept that living things come only from other living things; established by Louis Pasteur.

Francesco Redi

Conducted experiments showing maggots do not spontaneously appear in meat; flies lay eggs.

Lazzaro Spallanzani

Demonstrated that boiled, sealed broth remains sterile, undermining spontaneous generation.

Louis Pasteur

Disproved spontaneous generation with swan-neck flasks; founded pasteurization and germ theory.

Pasteurization

Heat treatment devised by Pasteur to prevent microbial spoilage (e.g., in wine or milk).

Germ Theory of Disease

Idea that microorganisms are the causative agents of many diseases.

Electron Microscope Discovery

Advancement that enabled visualization of viruses and sub-cellular structures in greater detail.

Genome Sequencing

Modern technique determining the complete DNA sequence of an organism, transforming microbiology.