micrbio study guide quiz 1

Prokaryotes (Akaryotes)

Unicellular organisms lacking membrane-bound organelles (like a nucleus) that contain a single circular chromosome, typically have a peptidoglycan cell wall, and divide via binary fission

Eukaryotes

Often larger and more complex organisms (unicellular or multicellular) that contain membrane-bound organelles, have multiple linear chromosomes, divide via mitosis/meiosis, and may or may not have cell walls

Pathogens

Microbes that cause infectious disease

Normal Flora

Also known as the "microbiome" of a host

Microbial Nomenclature

Scientific naming system that is always italicized, remains the same in every language, and consists of a genus and a species

Bacteria (Eubacteria)

A diverse prokaryotic domain featuring cell walls made largely of peptidoglycan; ubiquitous in nature, they can be motile or stationary, autotrophic or heterotrophic, and many act as pathogens

Archaea

The third Domain of life; a highly diverse prokaryotic group of extreme-living organisms (extremophiles) with odd or non-existent cell walls and no known pathogens

Protozoa

Eukaryotic, unicellular organisms that lack cell walls; most are motile, all are heterotrophic, and some are pathogens

Fungi

Eukaryotic organisms (unicellular or multicellular/dimorphic) with cell walls often containing chitin; always heterotrophic saprophytes, and some are pathogenic

Algae

Eukaryotic organisms (unicellular or multicellular) with cell walls composed largely of cellulose; always autotrophic photosynthesizers with no known pathogens

Helminths

Multicellular parasitic worms belonging to Kingdom Animalia that lack cell walls; some are pathogens

Viruses

Acellular, non-living infectious particles lacking independent metabolism; consist of DNA or RNA (never both), act as obligate intracellular parasites, and are usually species- and tissue-specific pathogens

Bioremediation

A field of microbial ecology that utilizes microbes to clean up and restore polluted environments

Bacillus

A rod-shaped bacterial cell

Coccus

A spherical bacterial cell

Spiral

A spiral-shaped bacterial cell

Monomorphic

Bacteria that consistently maintain a single, uniform shape

Pleomorphic

The characteristic of having variable or multiple cell shapes

Glycocalyx

A surface structure found outside the bacterial cell wall; exists as a slime layer or capsule, and is involved in forming biofilms

Appendages

Structures extending outside the bacterial cell wall, including flagella, fimbriae, pili, and axial filaments

Axial Filaments

Specialized motility appendages found exclusively in spirochetes

Peptidoglycan (PG)

The primary structural component of bacterial cell walls, composed of cross-linked chemical subunits

Gram-Positive Bacteria

Bacteria characterized by a very thick peptidoglycan layer, a thin periplasmic space, and the presence of teichoic/lipoteichoic acids

Gram-Negative Bacteria

Bacteria characterized by a thin peptidoglycan layer, an outer lipid membrane containing porins, and an extensive periplasmic space containing lipopolysaccharides (LPS)

Lipid A

The endotoxin component of the lipopolysaccharide (LPS) layer in Gram-negative bacteria

Mycobacterium spp.

Oddball bacteria that possess acid-fast cell walls

Mycoplasma

Oddball bacteria that completely lack a cell wall

Protoplast

A Gram-positive bacterial cell that has had its cell wall entirely removed

Spheroplast

A Gram-negative bacterial cell that has had its cell wall removed

Plasmids

Small, circular, extrachromosomal pieces of DNA that may be present inside bacterial cells

Endospores

Highly resistant, dormant structures produced only by certain bacterial genera (such as Bacillus and Clostridium) to survive harsh environments

Sporulation

The non-reproductive process where a vegetative bacterial cell transitions into a highly protective endospore

Germination

The process where a dormant endospore returns to an active, vegetative cell state