Chapter 1: Humans and the Microbial World

Vocabulary flashcards covering the history of microbiology, the dispute over spontaneous generation, the role of microbes in health and industry, and the classification of the microbial world.

Microorganism

Any organism too small to be seen with the naked eye, including bacteria, archaea, protists, algae, protozoa, and fungi.

Helminths

Parasitic worms which are microscopic in their egg and larval stages but typically macroscopic as adults.

Viruses

Acellular infectious particles that consist of DNA or RNA surrounded by a protein coat and are obligate intracellular agents.

Robert Hooke

The individual credited with the discovery of microbes who described a "microscopical mushroom" (common bread mold) in 1665.

Antonie van Leeuwenhoek

The scientist who made a simple microscope in 1674 to observe "animalcules" in lake water and dental plaque.

Spontaneous Generation

The theory, also known as abiogenesis, suggesting that living things can arise from nonliving matter.

Francesco Redi

The scientist who challenged spontaneous generation in the 1600s by showing that maggots never developed on decaying meat isolated from flies.

John Needham

A scientist who in the 1700s mistakenly reinforced the idea of spontaneous generation by showing that boiled beef gravy in sealed flasks became cloudy with microorganisms.

Lazzaro Spallanzani

A scientist who contradicted Needham’s findings by boiling infusions for an hour and sealing vials with wax, concluding that microorganisms exist in the air.

Louis Pasteur

The scientist who ended the dispute over spontaneous generation using swan-necked flasks to show that sterile broth remains sterile unless exposed to air contaminants.

John Tyndall

An English physicist who explained that Pasteur's results varied because different sterilization times were needed for different broths, particularly those containing hay.

Ferdinand Cohn

A German botanist who discovered endospores, the heat-resistant form of bacteria, in 1876.

Germ Theory of Disease

The principle that microorganisms are the cause of infectious diseases.

Scientific Method

A process involving making an observation, developing a testable hypothesis, designing experiments with controls, and drawing conclusions.

Scientific Theory

An explanation for a natural phenomenon that is supported by a large amount of evidence.

Normal Microbiota

The enormous population of microorganisms carried by the human body that plays essential roles in health, digestion, and immune development.

Human Microbiome Project

An initiative started in 2007 using DNA sequencing to characterize microbial communities inhabiting the human body.

Bioremediation

The commercial use of microorganisms to hasten the decay of environmental pollutants, such as oil spills.

Biotechnology

The use of microbiological and biochemical techniques to solve practical problems.

Genetic Engineering

A branch of biotechnology involving the production of medications (like insulin) or plants with desirable qualities using microorganisms.

Pathogens

Microorganisms that can cause disease, resulting in damage to body tissues.

Emerging Infectious Disease (EID)

A disease that has become more common in the last 35 years, such as Ebola, Zika, MERS, or AIDS.

Prokaryotic Cells

Cells that do not have a membrane-bound nucleus, characteristic of the domains Bacteria and Archaea.

Eukaryotic Cells

Cells that contain a membrane-bound nucleus and organelles, characteristic of the domain Eukarya.

Peptidoglycan

A unique chemical component found in the rigid cell walls of Bacteria but absent in Archaea and Eukarya.

Archaea

Single-celled prokaryotes similar in size and shape to bacteria but possessing different ribosomal RNA sequences and often living in extreme environments.

Fungi

A diverse group of eukaryotes ranging from single-celled yeasts to multicellular molds that use organic material for energy.

Algae

Photosynthetic eukaryotes that can be single-celled or multicellular and contain chloroplasts with chlorophyll.

Protozoa

Diverse, single-celled eukaryotes that lack a rigid cell wall and typically ingest organic compounds for energy.

Viroids

Acellular agents consisting only of a single short piece of RNA that cause plant diseases.

Prions

Infectious, misfolded versions of normal cellular brain proteins that cause spongiform encephalopathy.

Binomial System of Nomenclature

The two-word naming system for organisms consisting of the capitalized Genus and the lower-case specific epithet (species), both italicized.