Microbiology and Cell Biology Study Flashcards

Comprehensive vocabulary flashcards covering optics, microscopy techniques, historical theories, taxonomy, prokaryotic structures, and eukaryotic structures based on microbiology and cell biology lectures.

Microbial Fermentation

A metabolic process using bacteria, mold, or yeast to convert sugars (carbohydrates) into alcohol, gases, and organic acids, historically used to produce bread, cheese, wine, and beer.

Hippocrates

A Greek physician ($460\text{--}370\text{ BC}$) known as the 'father of Western medicine' who posited that diseases had natural causes from within patients or their environment rather than supernatural causes.

Thucydides

A Greek philosopher and historian ($460\text{--}395\text{ BC}$) known as the father of scientific history, who observed that survivors of the Athenian plague did not become re-infected, showing an early understanding of immunity.

Marcus Terentius Varro

A Roman writer ($116\text{--}27\text{ BC}$) who proposed in Res Rusticae ($36\text{ BC}$) that disease could be caused by unseen minute creatures (animalia minuta) floating in the air that enter the body via mouth and nose.

Antonie van Leeuwenhoek

A Dutch cloth merchant ($1632\text{--}1723$) who developed a powerful simple microscope and was the first to observe single-celled microorganisms in $1675$, describing them as 'animalcules' or 'wee little beasties'.

Louis Pasteur

A French chemist who demonstrated that fermentation is caused by microbes, disproved spontaneous generation using swan-neck flasks, developed pasteurization, and created vaccines for rabies.

Robert Koch

A German physician who demonstrated the connection between a single isolated microbe and a specific disease using a set of postulates, identifying the causative agents of anthrax (Bacillus anthracis), cholera (Vibrio cholerae), and tuberculosis (Mycobacterium tuberculosis).

Taxonomy

The science of classification, description, identification, and naming of living organisms into organized groups based on shared characteristics.

Binomial Nomenclature

A two-word naming system developed by Carolus Linnaeus that assigns each organism a Latinized scientific name consisting of a capitalized genus and a lowercase species name.

Carl Woese

An American microbiologist who, with George Fox, created a genetics-based tree of life using small subunit ribosomal RNA (rRNA) gene sequences, establishing the three-domain system: Bacteria, Archaea, and Eukarya.

Bergey's Manuals

Standard reference volumes (Bergey's Manual of Determinative Bacteriology and Bergey's Manual of Systematic Bacteriology) used for identifying and classifying prokaryotic organisms based on nonvisual and biochemical traits.

Strain

A genetic subtype or variation within a single species of microorganism, such as pathogenic Escherichia coli O157:H7 versus harmless intestinal E. coli.

Prion

An acellular, extremely small infectious agent composed solely of an abnormal protein (containing no DNA or RNA) that causes fatal neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD).

Spontaneous Generation

An ancient theory, articulated by Aristotle, proposing that living organisms can arise spontaneously from nonliving matter containing 'pneuma' or vital heat.

Francesco Redi's Experiment

A $1668$ experiment using open, cork-sealed, and gauze-covered meat containers that demonstrated maggots were the offspring of flies rather than products of spontaneous generation.

Swan-Neck Flask Experiment

An experiment designed by Louis Pasteur in $1858$ that allowed air exchange while trapping airborne microorganisms in a curved neck, irrefutably disproving spontaneous generation.

Cell Theory

A fundamental biological theory stating that all organisms are composed of one or more cells, cells are the basic structural units of life, and all cells arise from pre-existing cells.

Rudolf Virchow

A German pathologist who popularized modern cell theory in $1855$ with the phrase omnis cellula a cellula ('all cells arise from cells'), building on earlier unpublished evidence by Robert Remak.

Endosymbiotic Theory

The theory stating that mitochondria and chloroplasts originated when ancestral eukaryotic cells engulfed photosynthetic and aerobic prokaryotic cells, establishing a permanent symbiotic relationship.

Lynn Margulis

An American geneticist who resurrected and expanded the endosymbiotic theory in $1967$, presenting microscopic, genetic, and molecular evidence that eukaryotic organelles derived from prokaryotic ancestors.

Miasma Theory

The historical belief that diseases were caused by bad air or miasmatic odors emanating from decomposing organic matter.

Germ Theory of Disease

The scientific principle stating that specific diseases are caused by infections from specific microscopic pathogens within the body.

Ignaz Semmelweis

A Hungarian obstetrician who demonstrated in $1847$ that handwashing with chlorinated lime water by physicians dramatically reduced maternal mortality from puerperal fever.

Joseph Lister

A British surgeon who pioneered antiseptic surgery in $1867$ by introducing carbolic acid (phenol) spray disinfectant and mandating handwashing and surgical cleanliness.

Refractive Index

A measure of the extent to which a transparent material slows the transmission speed of light relative to empty space, causing light rays to bend when crossing media.

Numerical Aperture

A measure of a microscope lens's ability to gather light, directly affecting its optical resolution.

Immunofluorescence

A technique in fluorescence microscopy where fluorochromes are conjugated to antibodies (either primary in direct, or secondary in indirect) to identify specific disease-causing antigens or microbes.

Gram Staining

A differential staining procedure developed by Hans Christian Gram in $1884$ that distinguishes bacteria into gram-positive (purple) or gram-negative (pink) based on cell wall peptidoglycan thickness.

Acid-Fast Stain

A differential stain (such as Ziehl-Neelsen) used to detect gram-positive bacteria containing waxy mycolic acids in their cell walls, such as Mycobacterium tuberculosis.

Peptidoglycan

A polymer consisting of repeating disaccharide chains of $N\text{-acetylglucosamine}$ (NAG) and $N\text{-acetylmuramic acid}$ (NAM) cross-linked by peptide bridges, forming bacterial cell walls.

Plasmolysis

The process in plant or bacterial cells where the plasma membrane detaches and shrinks away from the rigid cell wall due to water loss in a hypertonic environment.

Volutin Granules

Inclusions (also known as metachromatic granules) that store polymerized inorganic phosphate used for cellular metabolism and biofilm formation.

Endospore

A highly resistant, dehydrated, and dormant structure formed within certain gram-positive bacterial cells (Bacillus and Clostridium) via sporulation to survive extreme heat, chemicals, and radiation.

Lipopolysaccharide (LPS)

An endotoxin located in the outer membrane leaflet of gram-negative bacteria, composed of Lipid A, a core polysaccharide, and an O antigen side chain.

Chemotaxis

The directional movement of a motile cell toward a chemical attractant or away from a repellent, regulated by changing the frequency of flagellar runs and tumbles.

Microbiology

The broad study of all types of microorganisms, including bacteria, archaea, fungi, protists, helminths, and viruses.

Amplitude

The height of a wave peak or depth of a trough.

Wavelength

The distance between one peak of a wave and the next peak.

Frequency

The rate of vibration of a wave, measured as the number of wavelengths passing per unit time.

Refraction

The change in direction of light rays as they pass from one medium into another with a different density.

Refractive Index

A measure of the extent to which a material slows down the transmission speed of light relative to empty space.

Focal Length

The distance from a lens to its focal point where parallel light rays converge.

Dispersion

The separation of white light into its component colors due to differing refractive indices for different light frequencies.

Resolution

The ability of a microscope to distinguish two separate points or objects as distinct structures.

Numerical Aperture

A measure of a microscope lens's ability to gather light.

Antonie van Leeuwenhoek

Dutch cloth merchant (1632–1723) who developed powerful simple microscopes and was the first to observe single-celled microbes, which he called animalcules.

Robert Hooke

English scientist (1635–1703) who published Micrographia (1665) and coined the term cells after observing dead cork tissue under a compound microscope.

Brightfield Microscope

A compound light microscope with two or more lenses that produces a dark image on a bright background.

Oil Immersion Lens

A specialized $100\times$ objective lens used with immersion oil to bridge the gap to the slide, matching the refractive index of glass and reducing light scattering.

Darkfield Microscope

A modified brightfield microscope containing an opaque light stop in the condenser, rendering unstained living specimens bright against a dark background.

Phase-Contrast Microscope

A microscope that uses an annular stop and phase plate to convert differences in refractive index into light intensity, producing high-contrast images of living, unstained cells.

Differential Interference Contrast (DIC) Microscope

A microscope (also known as Nomarski optics) that utilizes interference patterns between two polarized light beams to produce high-contrast, three-dimensional-appearing images.

Fluorescence Microscope

A microscope that uses fluorochromes to absorb high-energy ultraviolet or blue light and emit lower-energy visible light.

Immunofluorescence

A diagnostic technique using fluorochrome-conjugated antibodies to detect specific antigens on microbes.

Confocal Microscope

A microscope that uses a laser to scan multiple focal z-planes, generating two-dimensional optical sections that a computer assembles into three-dimensional images.

Transmission Electron Microscope (TEM)

An electron microscope that transmits an electron beam through thin specimen slices to view internal ultrastructures.

Scanning Electron Microscope (SEM)

An electron microscope that scans metal-coated specimen surfaces with electrons, creating detailed three-dimensional surface images.

Scanning Tunneling Microscope (STM)

A scanning probe microscope that uses a probe passed above a specimen under a constant voltage bias to map surfaces at the atomic level.

Atomic Force Microscope (AFM)

A scanning probe microscope that measures height variations of a tiny cantilever tip as it moves over a specimen to produce atomic-level images.

Wet Mount

A simple specimen preparation method where a sample is placed on a glass slide in a drop of liquid.

Fixation

The process of attaching cells to a microscope slide, typically achieved by heat-fixing or chemical treatment.

Basic Dye

A stain whose chromophore is a positively charged ion that binds to negatively charged cellular structures like bacterial cell walls (positive stain).

Acidic Dye

A stain whose chromophore is a negatively charged ion that is repelled by cell walls, coloring the background instead (negative stain).

Gram Staining

A differential staining procedure developed by Hans Christian Gram in 1884 that categorizes bacteria into gram-positive or gram-negative groups based on cell wall composition.

Mordant

A chemical agent, such as Gram's iodine, used to stabilize or set dyes by forming insoluble complexes inside cell structures.

Acid-Fast Stain

A differential staining method using carbolfuchsin to detect bacteria with waxy mycolic acids in their cell walls, such as Mycobacterium tuberculosis.

Capsule Staining

A negative staining technique that visualizes protective polysaccharide capsules surrounding certain microbes as clear halos against a stained background.

Endospore Staining

A differential staining technique using malachite green and safranin to distinguish dormant endospores from pink vegetative cells.

Flagella Staining

A staining procedure that coats delicate bacterial flagella with tannic acid or aluminum potassium sulfate mordants to increase their thickness for light microscopy.

Fermentation

A microbial process converting sugars to alcohol, gases, and organic acids using bacteria, mold, or yeast.

Miasma Theory

An ancient medical hypothesis proposing that diseases were caused by bad air or poisonous vapors emanating from decomposing matter.

Hippocrates

Greek physician (460–370 BC) known as the father of Western medicine, who posited that disease had natural rather than supernatural causes.

Thucydides

Greek historian (460–395 BC) known as the father of scientific history, who observed that survivors of the Athenian plague developed immunity to reinfection.

Marcus Terentius Varro

Roman writer (116–27 BC) who proposed in Res Rusticae that unseen minute creatures float in air and enter the body to cause disease.

Louis Pasteur

French chemist (1822–1895) who disproved spontaneous generation, demonstrated microbial fermentation, developed pasteurization, and created vaccines like rabies.

Robert Koch

German physician (1843–1910) who established postulates connecting specific microbes to specific human diseases, including anthrax, cholera, and tuberculosis.

Taxonomy

The formal practice of classifying, describing, identifying, and naming living organisms.

Carolus Linnaeus

Swedish botanist (1701–1778) who published Systema Naturae (1735) and established a standardized hierarchical taxonomy and binomial nomenclature.

Binomial Nomenclature

A standardized two-word naming system for organisms consisting of a capitalized genus and lowercase species name, both italicized.

Phylogenetic Tree

A diagrammatic representation depicting evolutionary relationships and shared ancestry among species.

Ernst Haeckel

German biologist who proposed adding the kingdom Protista (1866) and later Monera to the tree of life.

Robert Whittaker

American ecologist who proposed adding kingdom Fungi (1969) and creating the superkingdom levels Empire Eukaryota and Empire Prokaryota.

Carl Woese

American microbiologist who used small subunit ribosomal RNA (rRNA) sequencing to divide life into three domains: Bacteria, Archaea, and Eukarya.

Horizontal Gene Transfer

The passage of genetic material between non-offspring organisms of the same or different species, forming webs of life.

Bergey's Manuals

Standard reference texts (Determinative Bacteriology and Systematic Bacteriology) used by microbiologists to identify and classify prokaryotes.

Strain

A genetic subtype or variant of a microorganism species that may exhibit unique virulence or physiological traits.

Peptidoglycan

A structural mesh polymer of alternating NAM and NAG sugar chains linked by peptide cross-bridges, unique to bacterial cell walls.

Pseudopeptidoglycan

A cell wall component of archaea resembling peptidoglycan but containing different sugar and amino acid subunits.

Bacterial Morphologies

Common cellular shapes of bacteria, including coccus, bacillus, vibrio, coccobacillus, spirillum, and spirochete.

Redi's Experiment

An experiment conducted in 1668 demonstrating that maggots arise on meat only when flies lay eggs, challenging spontaneous generation.

Algae

Photosynthetic eukaryotic protists with cellulose cell walls that produce oxygen and carbohydrates.

Protozoa

Unicellular eukaryotic protists that lack cell walls and move using cilia, flagella, or pseudopods.

Helminths

Multicellular parasitic worms studied in microbiology because their transmission involves microscopic eggs and larvae.

Viruses

Acellular infectious entities composed of protein coats and DNA or RNA genomes (never both) that replicate strictly within host cells.

Prions

Acellular, proteinaceous infectious agents devoid of nucleic acids that cause fatal neurodegenerative diseases like CJD.

Spontaneous Generation

The ancient hypothesis asserting that living organisms can originate spontaneously from nonliving matter.

Biogenesis

The biological principle stating that all living cells arise only from pre-existing living cells.

Endosymbiotic Theory

The theory stating that mitochondria and chloroplasts originated as free-living prokaryotic cells that entered into symbiotic relationships with eukaryotic host cells.

Germ Theory of Disease

The principle that infectious diseases are caused by specific microorganisms invading host bodies.

Ignaz Semmelweis

Hungarian obstetrician (1818–1865) who demonstrated that handwashing with chlorinated lime water dramatically reduced puerperal fever mortality in mothers.