Exam1 Microbiology Vocabulary Review

A curated set of vocabulary flashcards covering key terms, people, structures, processes, and agents discussed in the microbiology lecture transcript. Use them to reinforce foundational concepts and prepare for exams.

Medical Microbiology

Branch that studies microbes causing diseases in humans and animals.

Agricultural Microbiology

Branch that examines microbes affecting crops, livestock, and soil fertility, including plant pathogens and biological pest control.

Industrial Microbiology

Field that safeguards food & water and applies biotechnology for large-scale production of products such as antibiotics, enzymes, and vitamins.

Environmental Microbiology

Study of microbial impact on earth’s habitats (soil, water, atmosphere), including subfields like geomicrobiology and astrobiology.

Louis Pasteur

French scientist who disproved spontaneous generation with the Swan-neck flask experiment, invented pasteurization, founded germ theory, and produced the rabies vaccine.

Swan-neck Flask Experiment

Pasteur’s broth study showing that sterile media remain microbe-free unless exposed to airborne organisms, refuting spontaneous generation.

Pasteurization

Mild heat treatment devised by Pasteur to reduce microbial load and spoilage in liquids such as milk and wine.

Germ Theory of Disease

Concept, championed by Pasteur and Koch, that specific microbes cause specific diseases.

Robert Hooke

First scientist to record microscopic observations of microbes (mold filaments) in 1660s.

Anton van Leeuwenhoek

Dutch tradesman who built simple microscopes and first described bacteria and protozoa (“animalcules”).

Robert Koch

German physician who devised postulates linking a particular microbe to a particular disease.

Koch’s Postulates

Four experimental steps used to prove that a microorganism causes a specific disease.

John Needham

Researcher whose inadequate boiling of broth failed to disprove spontaneous generation.

John Tyndall

Scientist who showed dust carries heat-resistant microbes (endospores) requiring stronger methods than boiling.

Endospore

Highly resistant, dormant bacterial structure produced mainly by Bacillus and Clostridium species to survive harsh conditions.

Joseph Lister

Surgeon who introduced antiseptic surgery via handwashing and phenol mist, greatly reducing post-operative infections.

Oliver Wendell Holmes

Physician who observed fewer infections in home births than hospital births, implicating hospital contamination.

Ignaz Semmelweis

Physician who reduced childbed fever by requiring handwashing between autopsies and deliveries.

Carl von Linné (Linnaeus)

Naturalist who established binomial nomenclature and hierarchical classification.

Binomial Nomenclature

Two-part Latin naming system giving each organism a Genus (capitalized) and species (lowercase).

Genus

First, capitalized part of a scientific name grouping closely related species.

Species (specific epithet)

Second, lowercase part of a scientific name identifying a single kind of organism within a genus.

Bright-field Microscope

Common light microscope that produces dark images on a bright background; routine lab work.

Dark-field Microscope

Light microscope producing bright specimens on a dark background; useful for live, unstained cells (e.g., spirochetes).

Phase-contrast Microscope

Optical system enhancing contrast of transparent cells to visualize intracellular structures without staining.

Differential Interference (DIC) Microscope

Light microscope generating high-contrast, pseudo-3D images of living cells.

Fluorescence Microscope

Instrument using fluorescent dyes or proteins excited by specific wavelengths to visualize structures.

Confocal Microscope

Fluorescence-based microscope providing sharp, optical sections and 3-D reconstructions.

Transmission Electron Microscope (TEM)

Electron microscope that transmits electrons through thin sections, revealing internal ultrastructure; essential for viewing viruses.

Scanning Electron Microscope (SEM)

Electron microscope that scans specimen surface, producing realistic 3-D images.

Simple Stain

Single dye (e.g., crystal violet, methylene blue) adding contrast to cells for morphology observation.

Gram Stain

Differential stain categorizing bacteria as Gram-positive (purple) or Gram-negative (pink/red) based on cell-wall peptidoglycan thickness.

Acid-fast Stain

Differential stain detecting mycolic-acid-rich bacteria (e.g., Mycobacterium tuberculosis) which appear red; others stain blue.

Endospore Stain

Differential stain that colors endospores green or red, distinguishing them from vegetative cells.

DNA Replication

Semi-conservative copying of DNA guided by enzymes such as helicase, DNA polymerase III, and ligase.

Transcription

Process where RNA polymerase synthesizes complementary mRNA from DNA template.

Translation

Ribosome-mediated decoding of mRNA codons into an amino-acid sequence (protein).

Horizontal Gene Transfer (HGT)

Movement of genes between contemporary cells rather than parent to offspring.

Conjugation

Direct HGT where a donor bacterium transfers plasmid DNA through a pilus to a recipient.

Transformation

Indirect HGT in which bacteria uptake free DNA fragments from the environment.

Transduction

Indirect HGT where bacterial DNA is transferred by a bacteriophage.

Transposon

“Jumping gene” able to move within or between DNA molecules (chromosome ↔ plasmid).

Spontaneous Mutation

Random DNA change arising from replication errors without external cause.

Induced Mutation

DNA change triggered by environmental mutagens such as chemicals or radiation.

Mutagen

Physical or chemical agent (e.g., UV light, X-rays) that damages DNA and increases mutation rate.

Point Mutation

Small change affecting a single nucleotide pair in DNA.

Missense Mutation

Point mutation that substitutes one amino acid for another in a protein.

Nonsense Mutation

Point mutation converting a sense codon into a stop codon, truncating the protein.

Silent Mutation

Base change that does not alter the encoded amino acid due to codon redundancy.

Frameshift Mutation

Insertion or deletion of nucleotides altering the reading frame, usually yielding nonfunctional protein.

Capsule

Thick, organized glycocalyx protecting bacteria from phagocytosis and aiding pathogenicity.

Fimbria (plural fimbriae)

Short, hairlike appendage that promotes adhesion of bacteria to surfaces and each other.

Flagellum

Long, whip-like structure enabling bacterial motility toward favorable environments.

Plasmid

Small, circular, extrachromosomal DNA molecule often carrying antibiotic-resistance or virulence genes.

Peptidoglycan

Net-like polymer of sugars and amino acids forming bacterial cell-wall backbone.

Gram-positive Cell Wall

Thick peptidoglycan layer with teichoic & lipoteichoic acids; lacks outer membrane.

Gram-negative Cell Wall

Thin peptidoglycan plus outer membrane containing lipopolysaccharide (endotoxin).

Lipopolysaccharide (LPS)

Outer-membrane molecule of Gram-negative bacteria; lipid A portion acts as endotoxin.

S-layer

Crystalline protein surface layer found in some bacteria and archaea, protecting against stress.

Cell Envelope

Collective term for bacterial cell membrane, cell wall, and in Gram-negatives, outer membrane.

Extremophile

Organism (often archaeon) thriving in extreme conditions such as high temperature, salinity, or acidity.

Protozoa

Unicellular eukaryotic microbes lacking cell walls; often motile via cilia, flagella, or pseudopods.

Fungi

Eukaryotes with chitinous cell walls; include yeasts, molds, and mushrooms; reproduce via spores.

Algae

Photosynthetic eukaryotes (unicellular or multicellular) with cellulose cell walls; produce oxygen.

Helminths

Parasitic multicellular worms (flatworms, roundworms) with microscopic eggs or larvae.

Interphase

Cell-cycle stage of growth and DNA replication preceding mitosis.

Prophase

First mitotic phase where chromatin condenses and spindle apparatus forms.

Metaphase

Mitotic stage where chromosomes align along the cell’s equatorial plane.

Anaphase

Mitotic stage where sister chromatids separate and move to opposite poles.

Telophase

Final mitotic stage where nuclear envelopes reform, chromosomes de-condense, and cytokinesis begins.

Virus

Acellular infectious agent consisting of nucleic acid enclosed in a protein capsid; obligate intracellular parasite.

Capsid

Protein shell of a virus protecting its nucleic acid genome.

Envelope (viral)

Host-derived lipid bilayer surrounding some viral capsids; defines enveloped viruses.

Spike (peplomer)

Viral envelope or capsid glycoprotein that binds specific host-cell receptors for attachment.

Baltimore Classification

System grouping viruses into seven classes based on genome type and route to mRNA.

Reverse Transcriptase

Enzyme in Classes VI & VII viruses that synthesizes DNA from an RNA template.

Persistent Infection

Long-term virus–host interaction where virus remains in cell without immediate lysis.

Provirus

Viral genome integrated into host DNA, remaining latent yet transmissible during cell division.

Bacteriophage

Virus that infects and replicates within bacterial cells; mediates transduction.

Prion

Infectious, misfolded protein causing neurodegenerative diseases like mad-cow and Creutzfeldt-Jakob.

Viroid

Small, circular RNA molecule lacking protein coat; infects plants and disrupts growth.