Study Guide Notes — Chapters 1 & 3 Microbiology

Comprehensive flashcard set covering Chapters 1 and 3 Microbiology notes: history of microbiology, key scientists, cell structure, taxonomy, cell walls, flagella, endospores, and comparison of the three domains.

Cellular Microorganisms

Organisms such as Bacteria, Archaea, and eukaryotic microbes that possess their own cell structure and can carry out metabolism and reproduction independently.

Acellular Microorganisms

Infectious agents such as viruses, viroids, satellites, and prions that lack a cell structure of their own.

Cytoplasmic Membrane

A cell structure common to all cells that serves as a barrier separating the inside of the cell from the outside environment.

Cytoplasm

An aqueous mixture of macromolecules, ions, and ribosomes found in all cells.

Ribosomes

Protein-synthesizing structures found in all living cells.

Cell Wall

A structural layer present in most microbes that confers structural strength.

Prokaryotic Nucleus Feature

Characterized by having no membrane-bound nucleus.

Eukaryotic Nucleus Feature

Characterized by having a true membrane-bound nucleus.

Prokaryotic Organelles Feature

Lacks any membrane-enclosed organelles.

Eukaryotic Organelles Feature

Contains membrane-enclosed organelles.

Prokaryotic Cell Size

Generally smaller compared to eukaryotic cells.

Eukaryotic Cell Size

Generally larger and more complex compared to prokaryotic cells.

Prokaryotic DNA Structure

Consists of a single circular chromosome that aggregates into the nucleoid.

Eukaryotic DNA Structure

Consists of linear DNA, usually with more than 1 chromosome (2 copies each), associated with proteins for folding.

Binary Fission

The mode of cell division characteristic of prokaryotes.

Mitosis

Eukaryotic cell division process used for non-sexual cell division.

Meiosis

Eukaryotic cell division process involved in sexual reproduction that halves the genome.

Prokaryotes vs Eukaryotes Comparison Table

A summary table comparing nucleus, organelles, size, DNA, and division features between Prokaryotes (Bacteria/Archaea) and Eukaryotes.

Metabolism

A characteristic common to ALL living cells involving the chemical transformation of nutrients.

Reproduction

A characteristic common to ALL living cells involving the generation of two cells from one.

Evolution

A characteristic common to ALL living cells involving genetic changes that are transferred to offspring.

Differentiation

A characteristic present in SOME living cells involving the synthesis of new substances or structures that modify the cell.

Cellular Communication

A characteristic present in SOME living cells involving the generation of, and response to, chemical signals.

Cellular Movement

A characteristic present in SOME living cells involving self-propulsion in various forms.

Carl Woese

Scientist who compared rRNA sequences in the 1970s and demonstrated that Bacteria and Archaea are two distinct prokaryotic groups.

Three-Domain System

The modern biological classification system dividing life into Bacteria, Archaea, and Eukarya based on Carl Woese's rRNA research.

Domain Bacteria

Domain of usually single-celled organisms with peptidoglycan cell walls, no membrane-bound nucleus, and widespread environmental presence.

Cyanobacteria

A group of bacteria within Domain Bacteria that produce oxygen ($O_2$).

Domain Archaea

Domain of organisms distinguished by unique rRNA sequences, unique membrane lipids, absence of peptidoglycan, and frequent occurrence in extreme environments.

Domain Eukarya

Domain of organisms that includes Protista and Fungi, characterized by membrane-bound nuclei and complex organelles.

Protista

A group within Eukarya that includes protozoa, algae, slime molds, and water molds.

Algae

Photosynthetic eukaryotic organisms within Protista that produce approximately $75\%$ of Earth's oxygen.

Protozoa

Eukaryotic microbes within Protista described as the 'hunters and grazers' of the microbial world.

Fungi

Eukaryotic saprophytes ranging from unicellular yeasts to multicellular mushrooms, used in food and antibiotic production.

Saprophytes

Organisms, such as fungi, that obtain nutrients from dead or decaying organic matter.

Viruses

Acellular infectious agents that require a host cell to replicate and cause diseases like smallpox, rabies, flu, and HIV/AIDS.

Viroids

Acellular infectious agents composed solely of RNA that cause plant diseases.

Satellites

Acellular infectious agents consisting only of RNA that cause plant and animal diseases, such as hepatitis.

Prions

Acellular infectious agents composed exclusively of protein that cause spongiform encephalopathies like scrapie and mad cow disease.

Lucretius & Fracastoro

Early thinkers who first suggested that invisible living creatures cause disease prior to the invention of the microscope.

Stelluti

Scientist who made the earliest microscopic observations (on bees and weevils) between 1625 and 1630.

Micrographia

The 1665 publication by Robert Hooke containing the first published drawings of microorganisms, including the fungus Mucor.

Robert Hooke

English scientist who published Micrographia in 1665 featuring drawings of the fungus Mucor.

Anton van Leeuwenhoek

Microscope builder ($50\text{--}300\times$ magnification) who first accurately observed and described bacteria and protists starting in 1673.

Francesco Redi

Italian physician who discredited spontaneous generation by demonstrating that maggots arise from fly eggs rather than decaying meat.

John Needham

Scientist who argued for spontaneous generation by showing that sealed, boiled mutton broth still grew microbes due to a supposed 'vital force'.

Lazzaro Spallanzani

Italian priest who showed that broth sealed prior to boiling remained sterile, proposing that air carried germs into uncovered broth.

Swan-Neck Flask Experiments

Experiments performed by Louis Pasteur in 1861 that disproved spontaneous generation by allowing air entry while trapping dust and microbes in the bend.

John Tyndall

Physicist who demonstrated that dust carries microorganisms, proving that broth remains sterile in dust-free air.

Ferdinand Cohn

Botanist who discovered that heat-resistant bacteria form endospores.

Agostino Bassi

Scientist who demonstrated that a silkworm disease was caused by a fungal infection.

M.J. Berkeley

Mycologist who proved that the Irish Potato Blight was caused by a water mold.

Heinrich de Bary

Plant pathologist who demonstrated that smut and rust fungi cause cereal crop diseases.

Joseph Lister

Surgeon who introduced antiseptic surgery using phenol to sterilize instruments and wounds, proving microbes cause wound infections.

Robert Koch

Physician who linked Bacillus anthracis to anthrax, established postulates proving germ theory, and won the Nobel Prize in 1905.

Jacob Henle

Teacher of Robert Koch whose criteria formed the basis for Koch's postulates.

Fanny Hesse

Assistant in Koch's laboratory who suggested using agar as a solidifying agent for culture media.

Richard Petri

Associate of Koch who invented the Petri dish for culturing microorganisms.

Florence Nightingale

Nursing pioneer who introduced cleanliness and aseptic technique into nursing during the Crimean War.

John Snow

Epidemiologist who mapped London cholera cases to a single public water pump, laying the foundation for public health.

Edward Jenner

Doctor who developed the smallpox vaccination around 1798 prior to the formal establishment of germ theory.

Pasteur & Roux

Researchers who discovered attenuation and developed vaccines for chicken cholera, anthrax, and rabies.

Attenuation

The process where repeated culture transfer reduces the pathogenicity of a microorganism, allowing its use in vaccines.

von Behring & Kitasato

Scientists who discovered diphtheria and tetanus antitoxins, providing evidence for humoral immunity.

Humoral Immunity Evidence

Demonstrated by von Behring and Kitasato through the discovery of protective antibodies and antitoxins in serum.

Elie Metchnikoff

Scientist who discovered phagocytic cells, providing early evidence for cellular immunity.

Cellular Immunity Evidence

Demonstrated by Elie Metchnikoff through his discovery of phagocytes that engulf invading microbes.

Winogradsky & Beijerinck

Microbiologists who studied soil microbes and nitrogen fixation, pioneering enrichment and selective culture media.

Germ Theory of Disease

The idea that specific microorganisms cause specific infectious diseases.

Pasteurization

Process developed by Louis Pasteur to heat a liquid enough to destroy or reduce undesirable microbes without ruining the product.

Koch's Postulate 1

The organism must be found in all cases of the disease and absent in healthy hosts.

Koch's Postulate 2

The organism must be isolated and grown in pure culture.

Koch's Postulate 3

Inoculating the pure culture into a healthy host must reproduce the disease.

Koch's Postulate 4

The organism must be re-isolated from that experimentally infected host and match the original.

Pure Culture Limitation

A limitation of Koch's postulates occurring when organisms cannot be grown in pure culture, such as the causative agent of leprosy.

Polymicrobial Infections

Infections caused by multiple organisms acting together (e.g., periodontal disease), presenting a limitation to Koch's postulates.

Taxonomy

The science of classifying organisms into hierarchical categories.

Binomial Nomenclature

System of naming organisms using Genus (capitalized) + species (lowercase), both italicized or underlined.

Taxonomic Classification Hierarchy

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

Domain

The most inclusive and highest taxonomic rank in biological classification.

Kingdom

The taxonomic rank below domain and above phylum.

Phylum

The taxonomic rank below kingdom and above class.

Class

The taxonomic rank below phylum and above order.

Order

The taxonomic rank below class and above family.

Family

The taxonomic rank below order and above genus.

Genus

The taxonomic rank above species, written capitalized and in italics or underlined.

Species

The most specific principal taxonomic rank, written in lowercase and in italics or underlined.

Coccus

A spherical or ovoid bacterial shape.

Diplococci

Bacterial arrangement consisting of pairs of cocci.

Neisseriae

Bacterial arrangement consisting of paired cocci with flattened adjacent sides.

Tetrads

Bacterial arrangement consisting of groups of four cocci.

Sarcinae

Bacterial arrangement consisting of cubical packets of 8 cocci.

Streptococci

Bacterial arrangement consisting of chains of cocci.

Staphylococci

Bacterial arrangement consisting of clusters or grape-like arrangements of cocci.

Bacillus

A rod-shaped bacterial cell morphology.

Coccobacilli

Short, oval rod-shaped bacteria intermediate between coccus and bacillus.

Spirillum vs Spirochete

Spirillum refers to rigid spiral shapes, whereas Spirochete refers to flexible spiral shapes.

Vibrios

Curved or comma-shaped rod bacteria.

Mycelium

A filamentous mass of hyphae forming a bacterial or fungal network.

Pleomorphic

Bacteria that display variable shapes and lack a single fixed form.