Ch 11-Microbiology: Bacteria and Archaea Flashcards

A comprehensive set of vocabulary flashcards covering the diversity, metabolic processes, and pathogenic characteristics of Bacteria and Archaea as described in Chapter 11.

Methanogens

A group of methane-producing archaea that oxidize $H_2$ gas to generate ATP and use $CO_2$ as a terminal electron acceptor.

Chemolithotrophs

Organisms that gain energy by oxidizing inorganic chemicals, such as hydrogen ($H_2$) or sulfur.

Desulfovibrio

The most studied genus of sulfur- and sulfate-reducing bacteria; they are Gram-negative curved rods that produce hydrogen sulfide ($H_2S$).

Tetanospasmin

A toxin produced by Clostridium tetani that blocks the release of inhibitory neurotransmitters at motor neurons, leading to constant muscle contraction (spastic paralysis).

Lactic Acid Bacteria

Anaerobic chemoorganotrophs that produce lactic acid as their primary end product of fermentation and lack the enzyme catalase.

Bacteriochlorophyll

Unique photosynthetic pigments found in anoxygenic phototrophs that absorb deep-penetrating wavelengths of light.

Cyanobacteria

The earliest oxygenic phototrophs; they use water as a source of electrons and often perform nitrogen fixation to convert $N_2$ to ammonia.

Nitrifiers

A diverse group of Gram-negative aerobic chemolithotrophs that oxidize inorganic nitrogen compounds, such as ammonium or nitrite, for energy.

Aquifex

A genus of thermophilic hydrogen-oxidizing bacteria that are obligate chemolithotrophs, with some species growing at temperatures as high as $95$ degrees Celsius.

Acid-fast bacteria

Bacteria such as Mycobacterium that contain mycolic acid in their cell walls, preventing standard Gram-staining and requiring specialized staining techniques.

Pseudomonas

Gram-negative rods with polar flagella that exhibit extreme metabolic diversity and are often capable of degrading environmental pollutants.

Coryneforms

Also known as diphtheroids, these are Gram-positive pleomorphic rods, such as Corynebacterium, that are often club-shaped and form V shapes or palisades.

Enterobacteriaceae

A group commonly referred to as "enteric bacteria," these are Gram-negative rods found in the intestinal tracts of humans and animals that ferment glucose.

Ecophysiology

The study of the adaptations of physiological mechanisms that prokaryotes use to live in terrestrial and aquatic environments.

Myxobacteria

Aerobic Gram-negative rods that exhibit a unique developmental stage where they congregate to form fruiting bodies and differentiate into dormant microcysts.

Streptomyces

A genus of aerobic Gram-positive bacteria that resemble fungi by forming a mycelium and producing conidia; they are major producers of medically useful antibiotics.

Ti plasmid

The specific plasmid from Agrobacterium tumefaciens that is transferred to plant tissue to encode the synthesis of plant growth hormones, resulting in a tumor.

Prosthecae

Extensions of the cytoplasm and cell wall, seen in genera like Caulobacter, that increase surface area for nutrient absorption or allow attachment.

Bdellovibrio

A genus of highly motile Gram-negative curved rods that act as parasites by preying on other Gram-negative bacteria like E. coli.

Luciferase

An enzyme found in bioluminescent marine bacteria that catalyzes the emission of light, often regulated by quorum sensing.

Spirochetes

Gram-negative spiral-shaped bacteria with a flexible cell wall and endoflagella (axial filaments) that allow for a corkscrew-like motion.

Thiomargarita namibiensis

A large prokaryote that can reach $0.75$ millimeter in diameter and contains a nitrate storage vacuole occupying approximately $98\%$ of the cell.

Bacteroides

Strictly anaerobic Gram-negative rods and coccobacilli that make up about one-third of the bacteria in human feces and are important for digestion.

Helicobacter pylori

A microaerophilic Gram-negative curved rod that causes ulcers and produces urease to neutralize stomach acid by breaking down urea to ammonia.

Mycoplasma

A genus of bacteria that lack a cell wall but contain sterols for strength; they are among smallest forms of life and produce "fried egg" colony appearances.

Treponema pallidum

The Gram-negative spirochete that causes syphilis, which is transmitted via sexual contact or from mother to child and has never been cultured.

Lyme disease

An infection caused by the spirochete Borrelia burgdorferi, which possesses a unique genome consisting of a linear chromosome and various plasmids.

Rickettsia rickettsii

The causative agent of Rocky Mountain Spotted Fever, an obligate intracellular parasite transmitted by hard ticks.

Elementary bodies

The dense-appearing, infectious form of Chlamydia and Chlamydophila that is released when a host cell ruptures.

Extreme Halophiles

Archaea found in salt lakes and brines that require at least $9\%$ $NaCl$ to grow, with most growing optimally at $32\%$ $NaCl$.

Methanopyrus kandleri

A methane-generating hyperthermophile that holds the current growth record at $122$ degrees Celsius.