General Microbiology – Exam 1 Vocabulary

Vocabulary flashcards that cover categories of microorganisms, cell types, historical figures, organic chemistry basics, bacterial morphology and structures, and Gram staining concepts for Chapters 1 & 3 review.

Bacteria

Single-celled prokaryotes with peptidoglycan cell walls; reproduce by binary fission and inhabit nearly every environment.

Archaea

Prokaryotes lacking peptidoglycan; often live in extreme environments such as high salt or high temperature.

Fungi

Eukaryotic organisms (molds, yeasts, mushrooms) that obtain nutrients by absorbing organic material from their environment.

Protozoa

Single-celled eukaryotes that are usually motile and live in aquatic or moist environments.

Algae

Photosynthetic eukaryotes that produce oxygen and form the base of many aquatic food chains.

Helminths

Parasitic worms (flatworms, roundworms) studied in microbiology because of their microscopic life stages.

Viruses

Acellular agents composed of nucleic acid surrounded by a protein coat; obligate intracellular parasites.

Prokaryote

A cell lacking a membrane-bound nucleus and organelles; includes bacteria and archaea.

Eukaryote

A cell containing a true nucleus and membrane-bound organelles; includes fungi, protozoa, algae, plants, and animals.

Pathogen

A microorganism or agent capable of causing disease in a host.

Louis Pasteur

French chemist who disproved spontaneous generation with the swan-neck flask experiment and pioneered fermentation and vaccination studies.

Swan-neck Flask Experiment

Pasteur’s experiment showing that microbes come from the air, not spontaneous generation, by keeping broth sterile in a curved-neck flask.

Abiogenesis (Spontaneous Generation)

The disproven idea that life can arise from nonliving matter spontaneously.

Biogenesis

The principle that living organisms arise only from pre-existing life.

Joseph Lister

Surgeon who introduced antiseptic techniques using carbolic acid, drastically reducing surgical infections.

Benefits of Microbes

Roles include nutrient cycling, food production, biotechnology, normal microbiota health effects, and bioremediation.

Carbohydrates

Organic molecules made of sugars; provide energy and structural support (e.g., cellulose, peptidoglycan).

Lipids

Hydrophobic molecules such as fats, phospholipids, and sterols; form membranes and store energy.

Proteins

Polymers of amino acids; perform enzymatic, structural, transport, and regulatory functions.

Nucleic Acids

DNA and RNA; store and transmit genetic information.

Coccus

Spherical bacterial shape.

Bacillus

Rod-shaped bacterium.

Vibrio

Comma-shaped, curved rod bacterium.

Spirillum

Rigid spiral-shaped bacterium with external flagella.

Spirochete

Flexible, corkscrew-shaped bacterium with axial filaments.

Diplo-

Prefix indicating bacteria arranged in pairs (e.g., diplococcus).

Strepto-

Prefix indicating bacteria arranged in chains.

Staphylo-

Prefix indicating grape-like clusters of cocci.

Flagellum

Long, whip-like appendage used for bacterial motility.

Fimbriae

Short, bristlelike protein fibers used for attachment to surfaces.

Pilus (Sex Pilus)

Longer protein appendage used for DNA transfer (conjugation) and attachment.

Monotrichous

Bacterial flagellar arrangement with a single flagellum at one pole.

Lophotrichous

Cluster of flagella at one pole of a bacterium.

Amphitrichous

Single flagellum at both poles of a bacterium.

Peritrichous

Flagella distributed over the entire bacterial surface.

Glycocalyx

Gelatinous polysaccharide/protein coating external to the cell wall that aids in protection, adherence, and biofilm formation.

Capsule

Organized, firmly attached form of glycocalyx that inhibits phagocytosis and enhances virulence.

Slime Layer

Loosely attached, unorganized glycocalyx aiding in surface attachment and water retention.

Peptidoglycan

Mesh-like polymer of sugars and amino acids forming the bacterial cell wall.

Cell Wall Function

Provides shape, prevents osmotic lysis, and anchors flagella in bacteria.

Gram Stain

Differential stain that classifies bacteria as Gram-positive or Gram-negative based on cell wall structure.

Gram-Positive Bacteria

Bacteria with thick peptidoglycan layers and teichoic acids; retain crystal violet stain and appear purple.

Gram-Negative Bacteria

Bacteria with thin peptidoglycan and an outer membrane containing LPS; lose crystal violet and take up safranin (pink).

Gram Staining Steps

1) Crystal violet, 2) Iodine, 3) Alcohol decolorizer, 4) Safranin counterstain.