Microbiology Quiz 1 Study Guide Summer 2026

Basic dyes

Stains with positively charged chromophores.

Gammaproteobacteria

The most diverse class of Proteobacteria containing the most human pathogens.

Staphylococcus aureus (nomenclature)

Staphylococcus is the genus; aureus is the species.

Amensalism

Symbiotic relationship where one population harms another while remaining unaffected.

Psychrophiles

Cold-loving microbes that grow best between 0-15 °C.

Psychrotrophs

Microbes that grow well between 4 °C and 25 °C; cause food spoilage.

Mesophiles

Microbes with an optimal growth temperature range of 20-40 °C.

Thermophiles

Microbes adapted to hot temperatures between 50-80 °C.

Hyperthermophiles

Microbes adapted to extreme heat between 80-110 °C.

Halophiles

Microbes that require high salt concentrations to grow.

Halotolerant

Microbes that do not require salt but can withstand up to 10% salt.

Barophiles

Microbes that grow best under high hydrostatic pressures.

Acidophiles

Microbes with optimal growth at pH 0-5.5.

Alkaliphiles

Microbes with optimal growth at pH 8.0-11.5.

Obligate anaerobes

Organisms for which oxygen is toxic; they cannot survive in its presence.

Facultative anaerobes

Microbes that thrive with oxygen but can grow without it via fermentation.

Microaerophiles

Microbes requiring low oxygen levels (1-10%) for growth.

Aerotolerant anaerobes

Microbes indifferent to oxygen; they do not use it but are not harmed.

Flagellar staining

Staining used to visualize tail-like structures used for bacterial locomotion.

Endospore staining

Staining used to identify structures that allow bacteria to survive harsh conditions.

Capsule staining

Staining used to visualize protective outer structures related to virulence.

Negative staining

Staining that colors the background but not the specimen, creating a halo.

Prokaryotic domains

Archaea and Bacteria.

Universal cell structures

All cells possess a cell membrane, cytoplasm, ribosomes, and DNA.

Rhizobium

Nitrogen-fixing bacteria that form nodules on legume roots.

Bdellovibrio

Predatory bacteria that invade the periplasmic space of gram-negative bacteria.

Bacteroides

Dominant human gut bacteria that prevent pathogen colonization.

Vector transmission

Transmission of an infectious agent via an animal carrier, like an arthropod.

Fomite

An inanimate object that can harbor and transmit pathogens.

Taenia saginata

Beef tapeworm contracted by ingesting undercooked, contaminated meat.

Endosymbiotic theory evidence

Mitochondria/chloroplasts have binary fission, circular DNA, and 70S ribosomes.

Lipopolysaccharide (LPS)

An endotoxin located in the outer membrane of Gram-negative bacteria.

Eukaryote ribosome size

80S ribosomes in the cytoplasm and rough endoplasmic reticulum.

Toxoplasma gondii

Protozoan parasite dangerous to pregnant women due to birth defect risks.

Gram staining steps

Crystal violet (stain), Gram's iodine (mordant), ethanol (decolorizer), safranin (counterstain).

Peptidoglycan backbone

Alternating polymers of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).

Teichoic acid

Acidic polymers found only in the cell walls of Gram-positive bacteria.

Helicobacter pylori

Bacterium that causes gastric ulcers and stomach cancer.

Robert Koch

Established postulates linking a specific microbe to a specific disease.

Louis Pasteur

Disproved spontaneous generation; developed rabies vaccine and pasteurization.

Carl Woese

Created the three-domain system based on rRNA sequence comparisons.

Anton van Leeuwenhoek

The first person to observe live microbes using simple microscopes.

Viroids

Acellular plant pathogens consisting only of short, circular RNA without a capsid.

Virus properties

Acellular, obligate intracellular parasites containing a DNA or RNA genome.

Trichomonas vaginalis

A flagellated protozoan that causes a sexually transmitted disease.

Fungal cell wall and membrane

Walls contain chitin; membranes contain ergosterol.

Enterobius vermicularis

Pinworm causing sleeplessness and intense itching around the anus.

Chlamydia

Obligate intracellular bacteria that cannot synthesize their own ATP.

Oligotrophs

Organisms capable of living in low-nutrient environments.

Prions

Infectious, misfolded proteins transmitted by contaminated tissue, not casual contact.

Pseudomonas aeruginosa

Opportunistic pathogen resistant to many antibiotics; forms biofilms in wounds.

Lichen

A symbiotic partnership between a fungus and an alga or cyanobacterium.

Naegleria fowleri

Brain-eating amoeba found in warm fresh water.

Encystment

Process where a trophozoite forms a protective wall to become a dormant cyst.

Varicella-zoster reactivation

Causes shingles, presenting as a painful blistering rash on one side.

Scolex

The head of a tapeworm, used to attach to host intestines using suckers/hooks.

Transmission Electron Microscope (TEM)

Best microscope for viewing internal cellular ultrastructure in high detail.

Apical complex

Specialized organelle arrangement in apicomplexans used to penetrate host cells.

Autotroph vs Heterotroph

Autotrophs use inorganic CO₂; heterotrophs use organic carbon sources.

Coliforms vs Noncoliforms

Coliforms ferment lactose completely; noncoliforms cannot or do so incompletely.