Microbiology Final Exam Review – Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering key terms, concepts, and individuals highlighted in Professor Foote’s microbiology final exam review.

Microorganism

A microscopic living organism such as bacteria, archaea, fungi, protozoa, algae, or viruses.

Aseptic Technique

Laboratory methods used to prevent contamination by unwanted microorganisms.

Germ Theory of Disease

Concept that specific microbes cause specific diseases.

Genus

Taxonomic category ranking above species and below family; first word in binomial name.

Species

Smallest taxonomic unit; group of similar organisms that can interbreed.

Bacteria

Prokaryotes with peptidoglycan cell walls that reproduce by binary fission.

Archaea

Prokaryotes without peptidoglycan that often inhabit extreme environments.

Fungi

Eukaryotes with chitin cell walls; include yeasts and molds.

Protozoa

Single-celled eukaryotes, often motile by flagella, cilia, or pseudopods.

Algae

Photosynthetic eukaryotes with cellulose cell walls that produce oxygen.

Virus

Acellular microbe composed of DNA or RNA in a protein coat; replicates only inside host cells.

Edward Jenner

Physician who created the first vaccine (cowpox) and introduced immunity concept.

Louis Pasteur

Scientist who disproved spontaneous generation, developed pasteurization, and supported germ theory.

Ignaz Semmelweis

Physician who reduced childbirth fever by introducing hand-washing.

Robert Koch

Microbiologist who developed Koch’s postulates to link microbes with disease.

Prokaryote

Cell lacking a true nucleus and membrane-bound organelles; 70S ribosomes.

Eukaryote

Cell with a nucleus and membrane-bound organelles; 80S cytoplasmic ribosomes.

Bacillus

Rod-shaped bacterium.

Coccus

Spherical bacterium.

Spirillum

Rigid, spiral-shaped bacterium.

Spirochete

Flexible, corkscrew-shaped bacterium.

Vibrio

Comma-shaped, curved rod bacterium.

Cell Wall (Bacteria)

Rigid layer of peptidoglycan that provides structural support.

Plasma Membrane

Selectively permeable phospholipid bilayer surrounding the cytoplasm.

Cytoplasm

Gel-like intracellular fluid where metabolic reactions occur.

Nucleoid

Region in prokaryotes containing circular DNA chromosome.

Ribosome (70S)

Prokaryotic structure that synthesizes proteins.

Gram-Positive Bacterium

Bacterium with thick peptidoglycan, no outer membrane, stains purple.

Gram-Negative Bacterium

Bacterium with thin peptidoglycan and outer membrane containing LPS; stains pink.

Teichoic Acid

Polymers in Gram-positive walls that provide rigidity and antigenic specificity.

Lipopolysaccharide (LPS)

Outer membrane molecule of Gram-negative bacteria; includes endotoxin lipid A.

Gram Stain

Differential stain using crystal violet, iodine, alcohol, and safranin to classify bacteria.

Inoculum

Sample of microbes introduced into culture medium.

Culture

Microbes growing on or in a nutrient medium.

Generation Time

Time required for a microbial population to double.

Aerobic

Requiring molecular oxygen for growth or metabolism.

Anaerobic

Growing without, or killed by, oxygen.

Biofilm

Complex community of microbes attached to a surface and embedded in extracellular matrix.

Selective Media

Growth medium that suppresses unwanted microbes and favors desired ones.

Differential Media

Medium that allows visible distinction between microbial types based on biochemical traits.

Enrichment Culture

Medium designed to increase numbers of rare microbes to detectable levels.

Lag Phase

Initial period of microbial growth curve with metabolic activity but no division.

Log Phase

Exponential growth phase where cells divide rapidly.

Stationary Phase

Growth equals death; nutrients deplete and wastes accumulate.

Death Phase

Cells die faster than they reproduce; population declines.

Sterilization

Removal or destruction of all microbial life, including endospores.

Pasteurization

Mild heat treatment that kills pathogens and reduces spoilage microbes.

Disk-Diffusion Test

Assay measuring antimicrobial drug effectiveness by zones of inhibition on an agar plate.

Catalase

Enzyme that breaks down hydrogen peroxide into water and oxygen.

Light Microscope

Instrument that uses visible light to magnify specimens up to ~1000–2000×.

Transmission Electron Microscope (TEM)

Electron microscope that provides high-resolution 2D images of internal structures.

Scanning Electron Microscope (SEM)

Electron microscope that produces 3D-like images of specimen surfaces.

Resolution

Smallest distance between two points that can be distinguished as separate.

Catabolism

Metabolic pathways that break molecules and release energy.

Anabolism

Energy-requiring synthesis of complex molecules from simpler ones.

Metabolism

Sum of all chemical reactions in a cell.

Metabolic Pathway

Series of enzymatically catalyzed chemical reactions in a cell.

Enzyme

Protein catalyst that speeds biochemical reactions.

Competitive Inhibitor

Molecule that binds an enzyme’s active site, blocking substrate access.

Noncompetitive Inhibitor

Molecule that binds an enzyme’s allosteric site, altering active site shape.

Feedback Inhibition

End-product of a pathway inhibits an early enzyme to regulate production.

Substrate-Level Phosphorylation

ATP formation by direct transfer of phosphate to ADP from a phosphorylated substrate.

Oxidative Phosphorylation

ATP synthesis powered by electron transport chain and chemiosmosis.

Glycolysis

Cytoplasmic pathway converting glucose to 2 pyruvate, yielding 2 ATP and 2 NADH.

Krebs Cycle

Series of reactions in which acetyl-CoA is oxidized to CO₂, producing NADH, FADH₂, and ATP.

Electron Transport Chain (ETC)

Membrane-embedded carriers that transfer electrons to generate proton motive force.

Cellular Respiration

Process of ATP generation using glycolysis, Krebs cycle, and oxidative phosphorylation.

Fermentation

Anaerobic process where pyruvate is reduced to regenerate NAD⁺ and produce 2 ATP per glucose.

Horizontal Gene Transfer

Movement of genes between organisms without reproduction (e.g., conjugation, transformation).

Missense Mutation

DNA change that substitutes one amino acid in a protein.

Nonsense Mutation

Mutation that converts a codon into a stop codon, truncating a protein.

Frameshift Mutation

Insertion or deletion that shifts reading frame, altering downstream amino acids.

Recombination

Genetic exchange between DNA molecules, creating new combinations.

Transcription

Synthesis of RNA from a DNA template by RNA polymerase.

Translation

Decoding mRNA into a polypeptide on ribosomes using tRNA.

Polymerase Chain Reaction (PCR)

Technique that amplifies specific DNA sequences via denaturation, annealing, and extension cycles.

Natural Selection

Process where beneficial mutations increase reproductive success, altering population genetics.

Artificial Selection

Human-directed breeding for desired traits.

Lytic Cycle

Viral replication that culminates in host cell lysis and release of progeny viruses.

Lysogenic Cycle

Phage DNA integrates into host genome and replicates silently as a prophage.

Latent Infection

Viral infection that remains dormant and can reactivate later (e.g., HSV).

Persistent (Chronic) Infection

Continuous, low-level viral replication causing gradual damage (e.g., HIV).

Prion

Infectious misfolded protein causing neurodegenerative diseases like CJD or mad cow disease.

Microbial Antagonism

Normal microbiota inhibit pathogen growth by competition and chemical production.

Opportunistic Infection

Disease caused by normally harmless microbes when host defenses are compromised.

Herd Immunity

Community protection achieved when most individuals are immune, limiting disease spread.

Epidemiology

Study of disease distribution, causes, and control in populations.

Incubation Period

Time between pathogen entry and symptom onset.

Prodromal Period

Short stage with mild, early symptoms.

Illness Period

Stage with most severe signs and symptoms.

Decline Period

Symptoms subside as immune response overcomes pathogen.

Convalescence

Recovery phase; host regains strength and tissue repair occurs.

Innate Immunity

Non-specific, rapid defense present at birth (e.g., barriers, phagocytes).

Adaptive Immunity

Specific, learned immunity involving B and T lymphocytes and memory.

Complement Activation

Cascade of proteins that enhance immunity, leading to opsonization, inflammation, and lysis.

Classical Pathway

Complement activation triggered by antibody-antigen complexes.

Membrane Attack Complex (MAC)

Complement proteins C5b-C9 forming a pore that lyses target cells.

Cytokine

Small protein messenger that regulates immune responses (e.g., TNF-α, interleukins).

Inflammation

Localized response to injury or infection marked by redness, heat, swelling, pain, and loss of function.

Vasodilation

Widening of blood vessels that increases blood flow to tissues.