Chapter 1: An Invisible World — Microbes, Diversity, and Taxonomy

Flashcards cover key concepts from the notes: microbial roles in environment, taxonomy, major microbial groups, historical roots of microbiology, and basic terminology.

What percentage of Earth's biomass is composed of microbes?

About 60%.

What are two ecological roles of microbes related to energy and decomposition?

They capture energy from sunlight and store it in molecules; they decompose dead organisms, waste, and some industrial wastes.

Which cyanobacterium is a major contributor to atmospheric oxygen?

Prochlorococcus.

What is one example of a symbiotic function of microbes as mentioned in the notes?

Symbiosis with other organisms to provide nutrients.

Which bacterium provides bioluminescence to lure prey in the Hawaiian bobtail squid?

Vibrio fischeri.

How are mushrooms related to fungi?

Mushrooms are the macroscopic reproductive bodies of microscopic fungi.

Name some industrial and consumer uses of microorganisms mentioned in the notes.

Fermentation to make beer, pickles, sauerkraut, yogurt; fructose for soft drinks; aspartame; use in cosmetics.

Who discovered penicillin and why is it important?

Sir Alexander Fleming discovered penicillin, the first widely used antibiotic.

Why is understanding infectious diseases important in health science careers?

To learn how diseases are transmitted and how to diagnose, treat, and prevent them.

Name three bacterial diseases listed in the notes.

Anthrax, Cholera, Tuberculosis.

Name three viral diseases listed in the notes.

HIV infection/AIDS, Dengue, Rabies.

How is microbiology commonly categorized?

By kind of organism (e.g., bacteriology, mycology) and by process or relation (e.g., metabolism, genetics, epidemiology), among others.

Give one example of a microbiology career shown in the notes.

Food microbiologist (others include environmental or veterinary microbiologist).

Who is considered the Father of Microbiology for observing living microorganisms?

Anton van Leeuwenhoek.

What were Pasteur’s and Koch’s major contributions?

Pasteur demonstrated microbial fermentation and pasteurization; Koch linked microbes to specific diseases and helped develop vaccines.

Who established the binomial nomenclature system and what are its basic rules?

Carolus Linnaeus; genus capitalized, species epithet lowercase, both italicized; first use full name, later abbreviated (e.g., Escherichia coli → E. coli).

Which three domains of life are recognized in the modern tree of life?

Bacteria, Archaea, and Eukarya.

What is the size range for most microbes?

From about 100 nanometers (viruses) to about 10 micrometers (many animal cells).

What are the six main microbial types covered in the course, and which are acellular?

Bacteria, Archaea, Protists, Fungi, Helminths, and Viruses; Viruses are acellular.

What is a key difference between bacterial and archaeal cell walls?

Bacteria typically have peptidoglycan; Archaea may have pseudopeptidoglycan or no peptidoglycan.

What type of lipids characterize archaeal membranes?

Branched lipids with ether bonds (as opposed to ester bonds in bacteria).

Are archaea known to cause disease in humans?

No, none are known to cause disease in humans.

How do algae and protozoa differ in nutrition?

Algae are autotrophic and photosynthetic; protozoa are mostly heterotrophic.

What are the two major subdivisions of fungi and a key characteristic of each?

Yeast (unicellular) and Mold (multicellular with hyphae); yeasts reproduce by budding or fission, molds by spores.

Why are helminths included in microbiology studies despite being multicellular?

Their diseases involve microscopic eggs and larvae, placing them in microbiology contexts.

What defines viruses, and why do they require host cells?

Viruses are acellular nucleic acid–protein entities that replicate only inside living host cells; they lack independent metabolism.

What are viroids and prions?

Viroids are naked nucleic acids causing plant diseases; prions are protein-only infectious agents with no nucleic acid.

What does LUCA stand for in the phylogenetic tree?

Last Universal Common Ancestor.

What were the major historical steps in taxonomy after Linnaeus (Haec) leading to the three-domain system?

Haeckel added Protista and Monera; Whittaker added Fungi; Woese and Fox established Bacteria, Archaea, and Eukarya domains.

What is a common bacterial shape and its name?

Coccus (spherical) or Bacillus (rod-shaped); other shapes include spirillum/spirochete.

What is a classic example of algae used to make agar and why is it significant?

Red algae are harvested to make agar, a medium used for growing bacteria.

How do bacteria differ from archaea in rRNA comparison?

Archaea’s rRNA is more similar to eukaryotes than to bacteria.

What is binomial nomenclature’s rule about abbreviating a species name after first use?

The genus may be abbreviated to its initial (e.g., Escherichia coli → E. coli).