Microbiology Lecture Review: Bacterial Appendages, Growth Media, and Identification Methods

Vocabulary practice flashcards covering bacterial morphology, flagellar arrangements, surface appendages, growth media types, and diagnostic methods from Chapters 1 through 4.

Basal Body

The motor structure of a bacterial flagellum that is embedded within the cell membrane and cell wall to drive rotation.

Flagellum Hook

An elbow-shaped protein joint connecting the basal body of a flagellum to its filament, allowing it to sweep like a propeller.

Flagellum Filament

A long, thin protein strand extending from the bacterial cell surface that provides locomotion.

Monotrichous

A flagellar arrangement pattern characterized by a single flagellum located at one spot on the cell.

Lophotrichous

A flagellar arrangement pattern featuring a tuft or cluster of flagella localized at one spot on the cell.

Amphitrichous

A flagellar arrangement pattern where flagella or filaments are present at both ends of the cell.

Peritrichous

A flagellar arrangement pattern in which flagella are distributed all over the perimeter of the cell.

Chemotaxis

Cellular movement in response to chemical stimuli, moving either toward an attractant (positive) or away from a repellent (negative).

Phototaxis

Cellular movement towards or away from a light source.

Spirillum

A spiral-shaped bacterial morphology characterized by having normal external flagella.

Spirochete

A spiral-shaped bacterial morphology that moves using internal periplasmic flagella (axial filaments).

Periplasmic Flagella

Internal flagella located in the periplasmic space of spirochetes that wrap around the cell axis to produce an inchworm-like motion.

Fimbriae

Small, short, numerous protein spikes that function like molecular Velcro to adhere bacteria to surfaces and other cells.

Pilus

A hollow protein tube composed of pilin that facilitates bacterial conjugation and surface adherence.

Conjugation

The transfer of genetic material (DNA) directly from one bacterial cell to another through a pilus.

Escherichia coli DNA Sequencing

The first bacterial species to have its total genome sequenced, which originally took $15\text{ years}$ and $150\text{ labs}$, but now takes $3\text{ to }4\text{ hours}$.

Agar

A polysaccharide isolated from Southeast Asian seaweed species used as a solidifying agent in microbial culture media.

Chemically Defined Media

Culture media where the exact chemical composition and specific quantity of every ingredient are known.

Complex Media

Culture media containing chemically undefined ingredients (such as extracts) used for general microbial culture.

Selective Media

Growth media formulated to allow specific microorganisms to grow while inhibiting the growth of unwanted flora.

Differential Media

Growth media containing specific ingredients that cause colonies of different organisms to grow in distinctive, predictable colors.

Transport Media

Media designed to maintain pathogen viability during transport (e.g., $48\text{ to }72\text{ hours}$) without allowing normal flora to overgrow.

Blood Agar

An enriched culture medium created by adding $5\%$ sheep blood to tryptic soy agar (TSA) to support fastidious clinical organisms.

Fastidious Bacteria

Organisms with special, complex nutritional requirements that require enriched growth media containing animal growth factors.

Chromagar

A differential medium used to identify urinary tract infection (UTI) pathogens based on color (e.g., E. coli grows pink, Proteus grows brown).

Prokaryote

An organism whose cells lack a membrane-bound nucleus and internal membrane-bound organelles.

Eukaryote

An organism whose cells contain a distinct, membrane-bound nucleus and specialized membrane-bound organelles.

Vibrio

A bacterial morphology characterized by a rigid, gently curved shape resembling a banana.