MICROBIO Ch1: Intro to Microbiology

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What is the approximate doubling time of bacteria?

~30 minutes

What are microbes?

Microscopic organisms including bacteria, viruses, fungi, protozoa, algae, helminths

What distinguishes prokaryotes from eukaryotes?

Prokaryotes: no nucleus or organelles; unicellular. Eukaryotes: nucleus and organelles; uni- or multicellular

Are viruses living? Why?

No; they cannot grow, reproduce independently, or carry out metabolism

What are helminths?

Parasitic worms (e.g., tapeworms)

What are cyanobacteria and why are they important?

Photosynthetic bacteria producing 40–50% of oxygen; can produce environmental toxins

Examples of harmful microbes?

Black mold, brain-eating amoeba, cyanobacteria toxins, red tide algae

Examples of beneficial microbes?

Probiotics, yeast in cheese, bacteria in food fermentation

Define nosocomial infection.

Infection acquired in a hospital

Define eukaryotes.

Organisms with a nucleus and membrane

Define prokaryotes.

Unicellular organisms without a nucleus or organelles

Viruses are composed of what?

Nucleic acid (DNA or RNA) and protein; acellular

What is microbial antagonism?

Competition among microbes and host; microbes modify metabolism to survive

What is microbial structure?

Prokaryotes: unicellular, no nucleus/organelles; Eukaryotes: uni

What is taxonomy?

Classification, naming, and identification of organisms

Who created the formal system of taxonomy?

Carl von Linne (Linnaeus)

What is binomial nomenclature?

Organism named as Genus + species (e.g., Escherichia coli)

Name the three domains of life.

Eukarya, Eubacteria, Archaea

What are extremophiles?

Archaea living in extreme environments: heat, cold, salt, acid, pressure

Give examples of extremophiles.

Thermophiles (heat), psychrophiles (cold), halophiles (salt), acidophiles (acid), barophiles/piezophiles (pressure)

Difference between Monera and Protista?

Monera: prokaryotes (bacteria); Protista: single

How do bacteria contribute to photosynthesis?

Cyanobacteria produce oxygen and glucose through photosynthesis

Define axenic environment.

Sterile environment with no microbes

What are exotoxins vs endotoxins?

Exotoxins: secreted; Endotoxins: within cell wall, released on cell death

What is pasteurization?

Heating food just enough to kill most microbes without boiling; slows microbial growth

Who disproved spontaneous generation?

Louis Pasteur

What is the Theory of Biogenesis?

Living things arise only from other living things

What did Anthony van Leeuwenhoek contribute?

First microscopic imaging of microbes; called them “animacules”

Who is Joseph Lister?

Introduced aseptic techniques to reduce wound infections in surgery

What are Koch’s postulates?

Steps to prove a microbe causes a specific disease:
1. present in all cases, absent in healthy

2. isolate & culture

3. Pure culture cause disease in healthy host

4. re-isolate and confirm microbe is identical

What are exceptions to Koch’s postulates?

Microbe cannot be cultured, multiple pathogens, ethical issues (Pure culture introduced to healthy host → causes same disease.)

What is a fomite?

Inanimate object that transmits pathogens or toxins

Who is John Snow?

Father of epidemiology; identified cholera source in London

What did Semmelweis and Holmes contribute?

Handwashing & hygiene reduced infections in hospitals

Difference between aerobic and anaerobic bacteria?

Aerobic: require oxygen; anaerobic: do not require oxygen

Define microbial metabolism.

Microbial processes to eat, grow, and divide

What is microbial ecology?

Study of interactions between microbes and their environment

What is the Golden Age of Microbiology?

Late 1800s; linking diseases to causative agents using Koch’s postulates

What fields of microbiology are organized by organism?

Bacteriology, virology, mycology, phycology, protozoology, parasitology

What are applied microbiology fields?

Industrial, pharmaceutical, food/beverage, infection control, genetic engineering

Name key contributions of Louis Pasteur.

Germ theory, disproved spontaneous generation, fermentation studies, pasteurization

How did Koch link microbes to disease?

Developed pure culture methods and postulates, identified anthrax, TB, cholera

What structural adaptation do pathogenic bacteria have?

Capsules to protect themselves from host defenses

What is the difference between Eubacteria and Archaea?

Eubacteria: typical bacteria with peptidoglycan cell walls. Archaea: genetically closer to eukaryotes, extremophiles, lack peptidoglycan

What is the significance of cyanobacteria in Earth's history?

Produced oxygen via photosynthesis, enabling the evolution of aerobic life

How do probiotics help humans?

Support gut metabolism, feed on prebiotics (fibers & vitamins), maintain healthy microbiome

What is nosocomial sepsis?

Infection caused by bacteria (often opportunistic) acquired in hospital settings

Why is microbiology important in research and biotechnology?

Microbes are easy to manipulate to study molecular pathways, genetics, and produce industrial/medical products

Fracastoro contributed what idea to microbiology?

Coined “fomite”; rejected spontaneous generation; “seeds of contagion” in air cause disease.

Did Van Leeuwenhoek invent the microscope?

No; microscopes came from the textile industry.

How can genus names be abbreviated?

First letter of genus + species (e.g., T. vaginalis).

What are the five major kingdoms of life?

Animals, plants, protists, monera, fungi.

What is unique about phylum classification in plants and animals?

Plants and animals do not use phylum levels in the same way as fungi.

What unit of measurement is used for bacteria?

Micrometers.

What is the relative size order of microbes from largest to smallest?

Algae (mm), protozoa (µm), bacteria (µm), viruses (nm).